Apr 202013
 

Electric Cables – What is Legal

conduits On Underlay509 Electric Cables

We get a lot of questions about which electric cables are legal and how they must be installed. So here is a brief rundown of the different types of legal cabling available and the way an installation could be done. There are various accepted methods and we illustrate a general one here. When a builder has to wire a home, he will first lay conduits, which are plastic or metal pipes fixed in place above the plastic damp-proof underlay and the steel reinforcing.  (See the picture above.)

These pipes are layed out according to the house plans and extend upwards from the floor, and will be built into the walls later when the bricklayers start their work. The concrete for the floors will then be placed, and the conduiting will run within the floor slab. From there they can be chased, or cut, into the walls so that they can be routed to various outlet points where plug points and lights are required. The electrician will later pull the wires through these tubes. There are classes of cable that do not need to be encased in conduit and can be chased into, and laid directly under the plaster. Two examples of these are Surfix and Flat-Twin-and-Earth cables. A full specification can be found in the Aberdare brochure below. When the roof is on and waterproof the cables can also be layed in the roof space for overhead lighting and other fittings.

Wiring electrician185 Electric Cables

A qualified electrician gets to work sorting out all the wires that come together at the distribution box.

Be Guided by What the Law Says about Electricicty and Electric Cables

By law a fully qualified and registered electrician must be  responsible for the wiring. It is a good idea for all homeowners to familiarise themselves with, and be able to identify, different types of cable and flex to ensure that all materials used in the installation are up to standard (literally – they need to meet the relevant South African National Standard).The National Building Regulations and Building Standards Act does not cover electricity and nor does SANS 10400. Electricians must comply with SANS 10142: The Wiring of Premises.

Depending on the class of cable the non-conductive insulation material around the wires inside cables and flex are different colours to make it easy to identify them. Green, or green and yellow, is the earth; live wires are brown or red; and neutral is either light blue or black. Once the wiring in a building is complete the entire system must be checked by an accredited person (from Eskom or the municipality/ local authority) who will issue a certificate of compliance.

Aberdare Cables have an excellent brochure (see below) that should help to identify the various cables associated with the electrical installation in a house.

Download (PDF, 2.47MB)

[Note that we have no affiliation with this company and reference to their brochure does not imply any particular recommendation.]

Apr 162013
 

Regs Glossary49 National Building Regulations Glossary

A to Z Glossary of Definitions and Terms Used in the National Building Regulation Code of Practice

 

Every industry has terms and definitions that are specific to that industry, and the building industry is no exception. These Building Regulation definitions form part of the National Building Regulations and Building Standards Act (Act 103 of 1977 that has been amended several times, most recently in 2008).

Note that every individual Standard in SANS 10400, which form a body of knowledge that shows those in the industry how to apply the South African Building Regulations, has its own bank of definitions at the beginning of the Standard. Many of these are the same as those published as part of the legislation.

All the individual Standards that form part of SANS 10400: The application of the National Building Regulations, also have a list of additional Standards (both South African and international) that are relevant to that part, and need to be taken into account during the building process.

 

A

Aircon562x100 s National Building Regulations Glossary

“absorption field” An on-site effluent system, such as a french drain or evapo-transpirative bed;

“acceptable”, “adequate” or “satisfactory means acceptable, adequate or satisfactory -

(a) in the opinion of any local authority; or

(b) in relation to any document issued by the council, in the opinion of the council;

“access” An approach, entry or exit;

“accessible” The characteristic of a building, that can be reached, entered and used;
NOTE Accessibility is evaluated in terms of the safe, comfortable and convenient use of the site, building or facility by persons with disabilities.

“accessible building” A building that complies with the requirements of part of SANS 10400-S:2011;

“accessible route” The walking space that complies with the requirements of part of SANS 10400-S:2011;

“access door” means an entrance door to an emergency route;

“accredited certification body” The certification body that has been accredited by a government-endorsed accreditation body;

“accredited testing laboratory” A laboratory that has been accredited by the South African National Accreditation System (SANAS);

“action” means an assembly of concentrated or distributed mechanical forces acting on a building or the cause of deformations imposed on the building or constrained in it;

“adequate” Adequate

a) in the opinion of any local authority, or

b) in relation to any document issued by the council, in the opinion of the council;

“agrément certificatemeans a certificate that confirms fitness-for-purpose of a non- standardised product, material or component or the acceptability of the related non-standardised design and the conditions pertaining thereto (or both) issued by the Board of Agrément South Africa;

“air conditioning system” means a system of mechanical ventilation where air that has been cleansed is supplied to a building under conditions of controlled temperature, humidity, distribution and movement;

“air duct” means any pipe, tube, conduit or enclosed space used or to be used in any building for the transmission of air in an artificial ventilation system;

“applicant” means any person who makes an application;

“application” means an application contemplated in section 4 of the Act;

“approval” means -

(a) approval by any local authority, including approval contemplated in section 7(7)(b) of the Act; or

(b) approval by the review board on appeal to the review board in terms of the Act;

“approved” means-

(a) approved by any local authority; or

(b) approved by the review board on appeal to the review board in terms of the Act;

“artificial ventilation system” means a system in which air is caused to circulate through a room by means of a mechanical apparatus which forces air into or extracts air from such room;

“articulation joint” A joint in masonry provided at suitable locations and intervals, that takes cognizance of the lateral stability and structural integrity of individual panels, and that enables wall panels to move in harmony with their supports without developing significant damage;

“automatic” in relation to fire-doors, fire-shutters, fire-dampers, fire-alarms, or fire extinguishing equipment means fitted with an approved device which is activated by a predetermined amount of heat, smoke, combustion gases or flame without the need for any manual operation;

 

B

Brick D E grey549x100 National Building Regulations Glossary

 

 

 

“backflow” means the flow of water in any pipe in a direction opposite to the normal direction of flow;

“back siphonage” means the backflow of water resulting from negative pressure in a water installation or in the water supply system;

“back vent” means a ventilating pipe connecting a branch discharge pipe, to which unvented fixture discharge pipes are connected, to a vent stack or to a stack vent;

“balustrade wall” means a wall serving the purpose of a balustrade;

“basement storey/basement” Any part of a building which is below the level of the ground storey;

“batten” A small section timber member, fixed parallel to the line of the eaves, at right angles to the rafters, and onto which tiles or slates are fixed;

“bearing” The structural support, usually a wall, positioned under the top chord or bottom chord or between the end points of a roof truss, beam or rafter;

“bed joint” The horizontal mortared joint between courses of masonry;

“block” means any masonry unit which has a length of more than 300 mm or a width of more than 130 mm;

“bond block” A masonry unit which is manufactured or modified on site to accommodate horizontal reinforcement within the depth of the unit;

“Board of Agrémentis the body that operates under the delegation of authority of the Minister of Public Works;

“branch discharge pipe” means a horizontal discharge pipe conveying the discharge from one or more sanitary fixtures to a discharge stack;

“branch drain” means any drain which discharges into a main drain;

“branch vent” means a horizontal ventilating pipe connecting two or more trap vents to a vent stack or to a stack vent;

“brandering” A small section timber member which is usually fixed to the underside of a truss chord to support a fixed ceiling;

“brick” means any masonry unit which is not a block;

“brickforce” A light, welded steel fabric that comprises two hard-drawn wires of diameter not less than 2,8 mm and not more than 3,55 mm, held apart by either perpendicular (ladder-type) or diagonal (truss-type) cross wires
NOTE Ladder-type brickforce usually has a main wire diameter that does not exceed 3,15 mm and is supplied
in rolls. Truss-type brickforce usually has a diameter of 3,55 mm and is supplied flat;

“building” includes:
a) any structure, whether of a temporary or permanent nature, and irrespective of the materials used in the erection thereof, erected or used in connection with

1) the accommodation or convenience of human beings and animals;

2) the manufacture, processing, storage, display or sale of goods;

3) the rendering of a service;

4) the destruction or treatment of refuse or other waste materials; and

5) the cultivation or growing of plants or crops;
b)  a wall, swimming bath, swimming pool, reservoir or bridge or any structure connected therewith;
c)  a fuel pump or tank used in connection therewith;
d)  any part of a building, including a building as defined in (a), (b) or (c); and
e)  any facilities or system, or portion thereof, within or outside but incidental to a building, for the provision of a water supply, drainage, sewerage, stormwater disposal, electricity supply or other similar service in respect of the building;

“building component” part of a building other than a building element;

“building element” wall, floor, foundation or roof of a building;

“building envelope” The elements of a building that separate a habitable room from the exterior of a building or a garage or storage area;

“building height” means the dimensional height in metres measured from the lowest ground level abutting any part of the building to the level of -

(a) the underside of a flat roof; or

(b) the underside of the roof of any plant room on such flat roof where the plan area of the plant room is more than 10% of the area of such flat roof; or

(c) a horizontal ceiling which is immediately under any pitched roof; or

(d) half-way between the eaves level and the ridge of any pitched roof where there is no ceiling below such roof or where the ceiling follows the pitch of such roof;

“building line” in relation to a site, means a line prescribed in any town planning scheme or any other law designating the boundaries of the area of the site outside of which the erection above ground of any building is prohibited;

 

C

Chimneyx100 96 National Building Regulations Glossary

 

 

 

“capacity” of any storage tank means the volume of such tank between the operating level of the water contained in such tank and the invert of the outlet from the tank;

“carport” means a building intended to provide shelter for a motor vehicle, caravan or boat and having a roof but having walls on not more than two sides;

“category 1 building”  A building which

a) is designated as being of class A3, A4, F2, G1, H2, H3, or H4 occupancy (see Regulation A20 in annex A),

b) has no basements,

c) has a maximum length of 6,0 m between intersecting walls or members providing lateral support, and

d) has a floor area that does not exceed 80 m2

NOTE 1 Table C.1 outlines the difference in performance between category 1 buildings and other buildings that have the same occupancy designation in respect of a number of building attributes.
NOTE 2 A building may be classified as a category 1 building for the purposes of one or more parts of SANS 10400. Additional limitations may accordingly be imposed on category 1 buildings. For example, a category 1 building in terms of SANS 10400-T (Fire protection) will be restricted to a single storey.
NOTE 3 Fire requirements for category 1 buildings are based on occupants escaping quickly from buildings. The design population for occupancies as set out in table 2 of part A of the Regulations (see annex A) should therefore not be exceeded.

“ceiling” The upper interior surface of a room or similar compartment, including all materials comprising such surface;

“certified thermal calculation software” Software that is certified by the Board of Agrément South Africa, in terms of Agrément South Africa’’s Energy Software Protocols, as being fit for thermal modelling or calculation purposes in terms of the National Building Regulations;

“chemical closet/toilet” means a closet/toilet with a fixed pan, the excreta from which pass into a tank where they are acted upon by chemicals which sterilize and break them down;

“chimney” means that part of a building which forms part of a flue, but does not include a flue pipe;

“chord” A main member that forms the outline of a truss;

“circulation space” The unobstructed area, for a minimum height of 2,1 m above finished floor level, within and around buildings, elements, fixtures and fittings required for movement into and within buildings;

“class 1 aggregate” Coarse aggregate of foamed slag, blast-furnace slag, pumice, burnt clinker, crushed limestone, crushed dolomite, crushed masonry unit or crushed burnt clay product;

“class 2 aggregate” Coarse aggregate of gravel or crushed natural stone other than limestone or dolomite;

“cleaning eye” means any access opening to the interior of a discharge pipe or trap provided for the purposes of internal cleaning, and which remains permanently accessible after completion of the drainage installation;

“clear opening width” The clear open space of an open door through which the user of a building passes
NOTE Clear opening width is not the same as the door width, as it also accounts for the thickness of the door, and any obstructions caused by door furniture on the door, or obstructions such as doorstops fixed to the floor or walls;

“clear span” The horizontal distance between the opposite faces of supporting walls;

“combustible” Is not classified as non-combustible when tested in accordance with SANS 10177-5;

“common drain” means that portion of a drain which conveys sewage other than or in addition to that sewage which emanates from the site through which such drain runs;

“common path of travel” The part of an escape route that leads to only one exit door, access door or escape door;

“communication pipe” means any pipe in a water supply system to which any water installation is connected;

“competent person” means a person who is qualified by virtue of his education, training, experience and contextual knowledge to make a determination regarding the performance of a building or part thereof in relation to a functional regulation or to undertake such duties as may be assigned to him in terms of these regulations;

“competent person” (built environment) A person who

a)  is registered in terms of the Engineering Profession Act, 2000 (Act No. 46 of 2000), as either a Professional Engineer or a Professional Engineering Technologist, or

b)  is registered in terms of the Architectural Profession Act, 2000 (Act No. 44 of 2000), as a Professional Architect or a Professional Senior Architectural Technologist, and

c)  is generally recognized as having the necessary experience and training to undertake rational assessments or rational designs in the field of roofs and roofing;

“competent person” (civil engineering)  A person who

a) is registered in terms of the Engineering Profession Act, 2000 (Act No. 46 of 2000), as either a Professional Engineer or a Professional Engineering Technologist,

b) has a tertiary qualification (degree or diploma) in civil engineering, and

c) is generally recognized as having the necessary experience and training to undertake rational assessments or rational designs in the field of civil engineering;

“competent person” (engineering geology) A person who is registered as a Professional Natural Scientist in terms of the Natural Scientific Professions Act, 2003 (Act No. 27 of 2003), and has a BSc (Hons) degree or higher qualification in engineering geology;

“competent person” (environmental access) A person who is

a) registered in terms of the Architectural Profession Act, 2000 (Act No. 44 of 2000), as either a Professional Architect, Professional Senior Architectural Technologist or a Professional Architectural Technologist, and has suitable contextual knowledge and experience to undertake a rational design or rational assessment in terms of the requirements of part S of the Regulations; or

b) generally recognized as having the necessary experience and qualifications to undertake a rational assessment and advise a Professional Architect, Professional Senior Architectural Technologist or Professional Architectural Technologist registered in terms of the Architectural Profession Act, 2000 (Act No. 44 of 2000), on a rational design in terms of the requirements of part S of the Regulations;

“competent person” (fire engineering) A person who

a) is registered in terms of the Engineering Profession Act, 2000 (Act No. 46 of 2000), as either a Professional Engineer or a Professional Engineering Technologist, and

b) is generally recognized as having the necessary experience and training to undertake rational assessments or rational designs in the field of fire engineering;

“competent person” (glazing) A competent person who is recognized by an institute, which has specialist expertise in the field of glazing, as generally having the necessary experience and training to determine glazing requirements in accordance with the requirements of SANS 10137;

“competent person” (mechanical engineering) A person who

a) is registered in terms of the Engineering Profession Act, 2000 (Act No. 46 of 2000),

b) has a tertiary qualification (degree or diploma) in mechanical engineering, and

c) is generally recognized as having the necessary experience and training to undertake rational assessments or rational designs in the field of lighting and ventilation;

“competent person” (sanitation) A person who

a) is registered in terms of the Engineering Profession Act, 2000 (Act No. 46 of 2000), as either a Professional Engineer or a Professional Engineering Technologist, and

b) has a tertiary qualification (degree or diploma) in either civil or mechanical engineering, and

c) is generally recognized as, or can furnish acceptable proof of, having the necessary experience and training to undertake rational assessments or rational designs in the field of sanitation;

“competent person” (wet services) A person who

a)  is registered in terms of the Engineering Profession Act, 2000 (Act No. 46 of 2000), as either a Professional Engineer or a Professional Engineering Technologist,

b)  has a tertiary qualification (degree or diploma) in civil engineering or mechanical engineering, and

c)  is generally recognized as having the necessary experience and training to undertake rational designs in the field of wet services;

“connecting sewer” means a pipe vested in the local authority which connects a drain to a sewer;

“conservancy tank” means a covered tank used for the reception and temporary retention of sewage and which requires emptying at intervals;

“consumer” means any person who is obtaining a supply of water from the local authority;

“contaminated land” means any land that, due to substances contained within or under it, is in a condition that presents an unacceptable risk to the health and safety of occupants of buildings constructed on such land;

“council” means the Council of the South African Bureau of Standards;

“cross vent” means a ventilating pipe connecting a discharge stack to a vent stack;

 

D

Discharge stackX100 National Building Regulations Glossary

 

 

 

“dark room” means any room used for the purposes of handling or processing light sensitive material;

“dead end” An area from which escape is possible in one direction only;

“dead-end corridor” means any corridor along which it is possible to travel only in one direction in order to reach a feeder route or emergency route;

“dead load” means the gravitational force caused by the static mass of all permanent parts of a building;

“deemed-to-satisfy provision” means non-mandatory requirement, the compliance with which ensures compliance with a functional regulation;

“deemed-to-satisfy rule” (or rule) means a non-mandatory provision which describes a method of design or construction that is deemed to comply with a particular functional regulation;

“depth of water seal” The quantity of water that would have to be removed from a fully charged trap before gases and odours at atmospheric pressure could pass through such trap;

“detached” Built separately as opposed to being attached horizontally with a common wall;

“developed length” of any pipe means the length between two specified points on such pipe measured along the centre line of such pipe, including any bend, junction or similar fitting;

“discharge pipe” means a pipe which conveys the discharge from a sanitary fixture to a drain, and includes a soil pipe, a waste pipe, a discharge stack, a branch discharge pipe or a fixture discharge pipe;

“discharge stack” means any vertical discharge pipe which conveys the discharge from two or more sanitary fixtures and which are connected directly to a drain;

“division” means a portion of a building separated from the remainder of such building by one or more separating elements;

“division wall” means an internal wall that separates one division from another division in any building and that has a fire resistance of not less than that required by these regulations;

“dolomite land” means land underlain by dolomite or limestone rock directly or at a shallow depth less than:

(a) 60 m in areas underlain by limestone;

(b) 60 m in areas underlain by dolomite where no de-watering has taken place and the local authority has jurisdiction, is monitoring and has control over the groundwater levels over the areas under consideration; or

(c) 100 m in areas underlain by dolomite where de-watering has taken place or where the local authority has no jurisdiction or control over ground water levels;

“domestic effluent” means sewage consisting of soil water or waste water or a combination of both;

“drain” means that part of any drainage installation outside a building and which is below ground level, but shall not include the following -

(a) any discharge pipe;

(b) that portion of a discharge stack which is below ground level;

(c) the bend at the foot of a discharge stack;

“drainage installation” means any installation vested in the owner of a site and which is situated on such site and is intended for the reception, conveyance, storage or treatment of sewage, and may include sanitary fixtures, traps, discharge pipes, drains, ventilating pipes, septic tanks, conservancy tanks, sewage treatment works, or mechanical appliances associated therewith;

“drencher system” means an approved system of piping and outlets which, when actuated manually or by the action of fire, releases a continuous curtain of water;

“drip”, (noun) A step or groove formed at the underside of a roof slab overhang parallel to the edge of the slab;

“dwelling house” means a single dwelling unit and any garage and other domestic outbuildings thereto, situated on its own site;

“dwelling unit” means a unit containing one or more habitable rooms and provided with adequate sanitary and cooking facilities;

 

E

Escape doorX100 National Building Regulations Glossary

 

 

 

“easy-to-use” The description of a fixture or fitting that has been designed and fitted in such a way that persons with disabilities are able to use it safely, comfortably and conveniently, both in terms of the mechanism used for its operation and the force required to operate it;

“electrical sanitary fixture” means a device which is connected to an electricity supply and to a water supply to perform a function such as the washing of clothes or dishes, or rendering waste matter suitable for disposal into a discharge pipe and includes a food-waste disposer, and a sanitary-towel disposer;

“emergency route” means that part of an escape route which provides fire protection to the occupants of any building and which leads to an escape door;

“entrance” Any access point to a building or portion of a building or facility, used for the purposes of entering.
NOTE An entrance includes the approach walk, thev ertical access leading to the entrance platform, the entrance platform itself, vestibule if provided, the entry door or gate, and the hardware of the entry door or gate.

“equipment” All control devices and components of systems other than appliances which are not permanently installed and integrated for the express purpose of providing control of environmental conditions for the building;

“escape door” means that door in an escape route which, at ground level, leads directly to a street or public place or to any approved open space which leads to a street or public place;

“escape route” means the entire path of travel from the furthest point in any room in a building to the nearest escape door and may include an emergency route;

“evapo-transpirative bed” means an effluent disposal system comprising a shallow sand-filled excavation covered with top soil and planted over with suitable vegetation;

“exit door” means any door that is a component of an escape route from any room;

 

F

Fire Installation National Building Regulations Glossary

 

 

 

“fall” The slope of a roof;

“feeder route” means that part of an escape route which allows travel in two different directions to the access doors to at least two emergency routes;

“fenestration” Any glazed opening in a building envelope, including windows, doors and skylights;

“fenestration area” An area that includes glazing and framing elements that are fixed or movable, and opaque, translucent or transparent;

“fire-damper” means an automatic damper and its assembly that complies with the requirements contained in SANS 193;

“fire-door” or “fire-shutter” means an automatic or self-closing door or shutter assembly especially constructed to prevent the passage of fire for a specific length of time;

“fire installation” means any water installation which conveys water solely for the purpose of fire-fighting;

“fire load” means the sum of the heat energy values of all combustible materials, including combustible partitions and other exposed combustible elements, contained in a compartment or division;

“fire resistance” means the shortest period for which a building element or component will comply with the requirements for stability, integrity and insulation when tested in accordance with SANS 10177-2;

“fire-stop” means a draft tight barrier or seal placed within or between building elements in shafts, voids and other concealed spaces to retard the spread of flame, heat or smoke;

“fixture branch” means a horizontal fixture discharge pipe;

“fixture discharge pipe” means a discharge pipe which conveys the discharge from a single sanitary fixture;

“fixture unit” means an arbitrary unit of measure for expressing the hydraulic loading on a drainage installation;

“fixture unit rating” means the value in fixture units assigned to a sanitary fixture from a consideration of the duration of its discharge, the interval between discharges and its mean discharge rate;

“flammable” means having a closed cup flash point lower than 90 °C;

“flat roof” A roof with a slight fall which is designed and constructed to allow rainwater to be shed by gutters, outlets or to the perimeter of the roof;

“flight” That part of a stairway which consists of consecutive steps between landings;

“floor area” in relation to a building or a storey thereof, means the total area enclosed within its external walls, exclusive of the area occupied by any lift shaft;

“floor drain” A pipe fitting into which waste water from the floor is discharged and that is normally connected to a branch discharge pipe, which conveys such discharge to a gully, a discharge stack or an open channel;

“floor joist” Is a horizontal beam which is the primary structural member in the construction of a timber floor;

“flooring board” A board of face side width not less than 50 mm and not more than 140 mm, which may be tongued on the one edge and grooved on the opposite edge;

“flight” means that part of a stairway which consists of consecutive steps;

“flue” means a passage which conveys the discharge of a heat generating appliance to the external air;

“flue pipe” means a pipe forming a flue but does not include a pipe built as a lining into a chimney;

“flush finish” The finishing of two adjacent surfaces in such a way that they provide no vertical or horizontal gap, gradient or camber that might affect the safe, comfortable and convenient passage of persons with disabilities;

“foundation” means that part of a building which is in direct contact with and is intended to transmit loads to the ground;

“foundation wall” means that portion of a wall between the foundation and the lowest floor above such foundation;

“free-standing wall” means a wall, not being a retaining wall, without lateral support;

“french drain” means a trench filled with suitable material which is used for the disposal of liquid effluent from a septic tank or waste water;

“functional regulation” means a regulation that sets out in qualitative terms what is required of a building or building element or building component in respect of a particular characteristic without specifying the method of construction, dimensions or material to be used;

 

G

Garage25 National Building Regulations Glossary

 

 

 

“garage” means an enclosed area which is used or intended to be used for the parking, storing, servicing or repairing of motor vehicles;

“gauge pressure” The amount by which the pressure exceeds the atmospheric pressure;

“general installation” means any water installation which conveys water for any purpose other than fire-fighting;

“geotechnical site investigation” the process of evaluating the geotechnical character of a site in the context of existing or proposed works or land usage, which may include one or more of the following:

(a) evaluation of the geology and hydrogeology of the site;

(b) examination of existing geotechnical information pertaining to the site;

(c) excavating or boring in soil or rock and the systematic description of the soil and rock profiles;

(d) determining the depth of any fill that might be present;

(e) in-situ assessment of geotechnical properties of materials;

(f) recovery of samples of soil or rock for examination, identification, recording, testing or display;

(g) testing of soil or rock samples to quantify properties relevant to the purpose of the investigation;

(h) evaluation of geotechnical properties of tested soils; and

(i) reporting the results;

“glazing” Glass, plastics and organic coated glass fixed in frames in windows, doors and roof lights, or that form doors;

“going” means the distance (measured on plan) between the nosing of a tread and the nosing of the tread or landing next above it;

“grab rail” A rail used as a support to transfer a person on or off a toilet, or to assist with other functions;

“grey water” Domestic waste water excluding toilet water;

“gully” means a pipe fitting incorporating a trap into which waste water is discharged;

 

H

Habitable Room414 National Building Regulations Glossary

 

 

 

“habitable room” means a room used or designed, erected, adapted or intended to be used by persons for sleeping in, living in, the preparation or consumption of food or drink, the transaction of business, the rendering of professional services, the manufacture, processing or sale of goods, the performance of work, the gathering together of persons or for recreational purposes;

“handrail” A rail used in circulation areas, such as corridors, passageways, ramps or stairways, to assist continuous and safe movement;

“heel joint” The position on a truss at which the top chords and bottom chords intersect, or where the first vertical web intersects with the bottom chord in stub-ended trusses;

“height” means building height;

“high risk substance” means any substance listed in the schedule to the Administrative Regulations, as amended, made in terms of the Machinery and Occupational Safety Act, 1983 (Act 6 of 1983);

“horizontal” in relation to a discharge pipe or ventilating pipe, means inclined at less than 45° to the horizontal;

 

I

Inspection Eye176 National Building Regulations Glossary

 

 

 

“impaired” A lower than generally accepted optimum performance in a human ability, which might be a temporary or permanent condition;

“impairment” Is indicative of any one impaired ability;

“imposed load” means any force assumed in the design of any building, caused by the intended occupancy thereof or by earth pressure, snow, hail, groundwater or the pending of rainwater;

“industrial effluent” means any liquid whether or not containing matter in solution or suspension which is given off in the course of or as a result of any industrial, trade, manufacturing, mining or chemical process or any laboratory, research or agricultural activity, and includes any liquid other than soil water or stormwater;

“inspection” means the general inspection by a competent person of a system or measure or installation of a building, or part thereof, at such intervals as might be necessary in accordance with accepted professional practice to enable such competent person to be satisfied that the design assumptions are valid, the design is being correctly interpreted and the work is being executed generally in accordance with the designs, appropriate construction techniques and good practice but shall exclude detailed supervision and day-to-day inspection;

“inspection chamber” means a chamber not deeper than 750 mm and of such dimension that access may be obtained to a drain without requiring a person to enter into such chamber;

“inspection eye” means any access opening to the interior of any pipe or pipe fitting in a drainage installation provided solely for the purpose of inspection and testing, and to which permanent access after completion of the drainage installation need not be provided;

“interceptor” A device that

a)  is designed to cool down incoming hot waste water to below 30 °C to enable grease and fat to separate from the water and to solidify or be collected on the surface level of the waste water, and that prevents grease and fat from entering a sewer; or

b)  separates and stores light liquid hydrocarbons from effluent water and stormwater, to prevent the light liquids from entering a sewer;

“interconnected complex” A complex of multiple dwelling units, such as terraced or multi-storey complexes, or cluster or retirement-village-type developments (or both), where management of common property usually resides with (but is not limited to) a management body;

 

L

Laminated Glass National Building Regulations Glossary

 

 

 

“laminated glass” means two sheets of ordinary annealed glass bonded to a shear and impact resistant plastic interlayer;

“laminated toughened glass” means a laminated glass where one or both sheets of ordinary annealed glass are replaced by a sheet or sheets of toughened glass;

“landing” means a platform between two consecutive flights of a stairway;

“lapa” Thatched roof building which is used for recreational purposes and has either no walls or non-combustible walls;

“lateral boundary” means a boundary of a site other than a boundary between such site and any street or public place with a width of more than 6 m measured at right angles to such boundary;

“light liquid” A liquid of a lower density than water, that is insoluble or only slightly soluble or only very slightly soluble in water, is non-saponifiable and non-polar (for example, naphthous oils, lubricating oils, diesel and fuel oils (but excluding emulsions and vegetable and animal fats and oils));

“light reflectance value” – LRV The measurement, using a spectrophotometer, of the light reflected from a surface in standard conditions;
NOTE It is expressed on a scale of 0 to 100, with black being about 5 and white about 90.

“lining” Internal surface finishing material, which may be partially or completely fixed or adhered to a substrate such as a wall, ceiling, roof or roof covering;

“load” means the value of a force corresponding to an action;

 

M

Masonry 74 National Building Regulations Glossary

 

 

 

“main drain” means the longest run of drain from a building to a common drain, to a means of sewage disposal situated on the site concerned, or to a connecting sewer;

“main entrance” The entrance that leads directly to

a) a reception area or point that provides information about the building or services within it, or

b) the primary stairway or lift foyer;

“maintained” The condition of operational readiness at all times in accordance with the original design and installation and associated maintenance procedures;

“make-up air” Air introduced to replace extracted air;

“manhole” means a chamber of a depth greater than 750 mm and of such dimension that allows entry of a person into such chamber for the purpose of providing access to a drain;

“masonry wall” means an assemblage of masonry units joined together with mortar or grout;

“means of access” The means of entering a building, site of buildings or building complex, and safe egress from the building, site of buildings or building complex, including the use of all facilities within and around the building, site of buildings or building complex;
NOTE The means of access relates to the safety, comfortable and convenient use of both the building, site of buildings or building complex and the facilities within it for persons with disabilities.

“mezzanine storey” means any mezzanine storey the floor area of which does not exceed 25% of that of the floor below it;

“minor building work” as contemplated in section 13 of the Act means-

(a) the erection of any-
(i) poultry house not exceeding 10 sq m in area;
(ii) aviary not exceeding 20 sq m in area;
(iii) solid fuel store not exceeding 10 sq m in area and 2 m in height;
(iv) tool shed not exceeding 10 sq m in area;
(v) child’s playhouse not exceeding 5 sq m in area;
(vi) cycle shed not exceeding 5 sq m in area;
(vii) greenhouse not exceeding 15 sq m in area;
(viii) open-sided car, caravan or boat shelter or a carport where such shelter or carport does not exceed 40 sq m in area;
(ix) any free-standing wall constructed of masonry, concrete, steel, aluminium or timber or any wire fence where such wall or fence does not exceed 1,8 m in height at any point above ground level and does not retain soil;
(x) any pergola;
(xi) private swimming pool;
(xii) change room, not exceeding 10 sq m in area, at a private swimming pool;

(b) the replacement of a roof or part thereof with the same or similar material;

(c) the conversion of a door into a window or a window into a door without increasing the width of the opening;

(d) the making of an opening in a wall which does not affect the structural safety of the building concerned;

(e) the partitioning or the enlarging of any room by the erection or demolition of an internal wall if such erection or demolition does not affect the structural safety of the building concerned;

(f) the erection of any solar water heater not exceeding 6 sq m in area on any roof or 12 sq m when erected other than on any roof; and

(g) the erection of any other building where the nature of the erection is such that in the opinion of the building control officer it is not necessary for the applicant to submit, with his application, plans prepared in full conformity with these regulations;

 

N

Nosing stairs726 National Building Regulations Glossary

 

 

 

“nail plate” A steel plate punched to form a nail pattern integral with the plate, and which is used as a structural connector;

“natural ventilation” means the movement of air through a building due to natural causes;

“nett floor area” The floor area excluding the area occupied by vertical elements, including enclosed lift wells and enclosed stairs;

“non-combustible” means classified as non-combustible when tested in accordance with code of practice SANS1 0177-5;

“non-return valve” (reflux valve) A water fitting that automatically permits flow to occur in one direction only;

“non-structural wall” means a wall which does not form part of a structure but which may from time to time be subject to forces other than its own weight;

“nosing” means the front edge of a tread and includes the front edge of the top surface of any landing which is situated at the top of a flight;

 

O

One pipe034 National Building Regulations Glossary

 

 

 

“obstruction” means any building or other object which partially or completely intersects any zone of space serving a window but shall not include any narrow object such as a pole or railing which does not materially obstruct the entry of light and air to the opening concerned;

“obstruction” – Part-S Is any of the following:

a)  anything impeding or preventing passage or progress in relation to a building or facility, which denies or removes from persons with disabilities, any supporting or enabling facility for their functioning within the building or facility; or

b)  obstacles that unfairly limit or restrict persons with disabilities from enjoying the opportunities provided within a building or facility on equal terms with persons without disabilities.
NOTE The failure to take steps to reasonably accommodate the needs of persons with disabilities within the building or facility can also be seen as a type of obstruction.

“occupancy” means the particular use or the type of use to which a building or portion thereof is normally put or intended to be put. Regulation A20 classifies and designates occupancies (see SANS 10400-A);

“offset” The deviation of the flow in the vertical plane of the discharge stack.
NOTE An offset in a discharge stack is normally accomplished with the use of two bends, the first to direct the flow from a vertical direction to a horizontal direction, and the second to direct the flow back to the vertical position (in the same flow direction).

“one-pipe system” means a system of piping between sanitary fixtures and a drain in which both waste and soil water discharge down a common discharge stack and in which any trap venting or other venting that is required may be via a common vent stack;

“operating water level” means the level of water reached in any storage tank when the valve controlling the inlet of water to such tank closes under normal operating conditions;

“orientation” The direction that a building envelope element faces, i.e. the direction of a vector perpendicular to and pointing away from the surface outside of the element;

“outside air” means air which is drawn into the building from the outside and which has not been circulated through such building;

“overflow gully” means a gully which allows the overflow of sewage but prevents the ingress of foreign matter, including rainwater directly from above;

 

P

Persons Disabilities National Building Regulations Glossary

 

 

 

“pail toilet” A toilet with a removable pail which is systematically emptied or replaced;

“pane” A piece of glazing material cut to the size and shape required for glazing;

“partition” means an interior construction less than one storey in height and is generally of a light construction and is demountable;

“partition wall” means a non-structural internal wall extending to the ceiling and constructed for the purpose of subdividing a space;

“path of travel” The circulation route or circulation space normally used by persons using the site, building or facility, including all external and internal routes and spaces in common usage, and the entrances and exits within these routes and spaces;

“percolation rate” The rate at which clean water, under a constant or nearly constant hydraulic head, percolates into the surrounding soil in both vertical and horizontal directions;

“performance” behaviour of a building as a whole or any part of it related to use;

“permanent access” The entrance to the interior of a drainage installation that remains accessible after completion of the installation;

“persons with disabilities” means those persons who have long-term physical, mental, intellectual or sensory impairments which in interaction with various barriers might hinder their full and effective participation in society on an equal basis with others;

“pitch” The angle of inclination of rafters to the horizontal, or angle of inclination of the surface on which tiles or sheeting is laid;

“pitch line” means a notional line which connects the nosings of all the treads in a flight or stairs;

“plastering” The application of a suitable plaster, sand, Portland cement and water to masonry interiors and exteriors to achieve a smooth surface;

“population” means the population determined in accordance with regulation SANS 10400-A21;

“prefabricated septic tank” A single-piece factory-made unit, including inlet and outlet openings, which leaves the factory completed, controlled and ready for installation;

“prescriptive regulation” means a regulation which describes in some detail an operation to be performed, or the dimensions of a building, building element or building component and the materials and method of construction to be used in such building, building element or building component;

“prescriptive rule” means a rule or regulation which describes in some detail an operation to be performed, or the dimensions of a building, building element or building component and the materials and method of construction to be used in such building, building element or building component;

“pressurization” means the creation of a positive air pressure differential between one area of and the remainder of a building and “pressurized” shall have a corresponding meaning;

“public place” means any square, park, recreation ground or open space which-

(a) is vested in the local authority; or

(b) the public has the right to use; or

(c) is shown on a general plan of a township filed in a deeds registry or a Surveyor-General’s office and has been provided for or reserved for the use of the public or the owners of erven in such township;

“purlin” The horizontal member attached to, and placed perpendicular to, the rafter in order to support roof sheeting materials;

 “purlin beam” A beam that is parallel to the eaves and that serves the purpose of a rafter;

 

R

Range 759 National Building Regulations Glossary

 

 

 

“rafter” – top chord. The horizontal or inclined member that establishes the upper edge of a truss or general roof line;

“rafter beam” The sloping roof member of engineered or rational design size that supports the roof covering material with or without the use of purlins or battens;

“ramp” An internal or external walkway with a slope between 1:20 and 1:12, in the direction of travel;

“range” means a number of like sanitary fixtures closely spaced and discharging to a common branch discharge pipe which does not receive the discharge from any other sanitary fixture not in the range;

“rational assessment” means assessment by a competent person of the adequacy of the performance of a solution in relation to requirements including, as necessary, a process of reasoning, calculation and consideration of accepted analytical principles, based on a combination of deductions from available information, research and data, appropriate testing and service experience;

“rational design” means any design by a competent person involving a process of reasoning and calculation and which may include a design based on a standard or other suitable document;

“reference building” A hypothetical building that is used to determine the maximum allowable energy load for the proposed building;

“refuge” An area that is separated from a fire by a fire-resistant construction, that is provided with a safe route to a storey exit, and that constitutes a temporarily safe place for persons to wait for assistance for their evacuation;

“regulation” (NBR) means national building regulation;

“rendering” The application of a thin premixed surface of sand, cement and lime plaster to a masonry surface;

“resealing trap” means a trap so designed that some of the water forming its seal is retained during siphonic action to reseal after siphonage has been broken;

“retaining wall” means a wall intended to resist the lateral displacement of materials;

“riser” The vertical distance between the tread of a step and the tread of the step immediately above it;

“rodding eye” means an access opening in a drainage installation provided for the purposes of gaining full-bore access to the interior of a drain for internal cleaning, and which remains permanently accessible after completion of the installation, but does not include an inspection chamber or manhole;

“roof assembly” The building cover and its supporting structure, including any ceiling attached to such structure and any additional components such as insulation;

“R-value” The thermal resistance (m2·K/W) of a component
NOTE This is the inverse of the time rate of heat flow through a body from one of its bounding surfaces to the other surface for a unit temperature difference between the two surfaces, under steady state conditions, per unit area;

 

S

Safety Glass National Building Regulations Glossary

 

 

 

“safety distance” means the distance provided between any building and the lateral boundary of the site, or where there are two buildings on the same site, the distance provided between each such building and a notional boundary line between them, so that spread of fire from one building to another due to effect of radiant heat will be minimized;

“safety glass” means a safety glazing material consisting primarily of glass;

“safety glazing material” means any material which complies with the requirements for the performance of safety glazing materials contained in SANS 1263-1;

“sanitary fixture” means a receptacle to which water is permanently supplied, and from which waste water or soil water is discharged;

“sanitary group” A combination of sanitary fixtures comprising not more than one each of a toilet pan, bath, shower and sink and either two washbasins or one washbasin and one bidet;

“secondary entrance” An entrance that is not the main entrance, and that leads directly to

a) a reception area or point that provides information about the building or services within it; or

b) the primary stairway or lift foyer;

“self-cleaning trap” A trap that, when tested with glass balls in accordance with the test method given in annex F of ISO 9896:1996, will allow at least 70 % of the balls to pass;

“self-closing” in relation to a door, fire-door, shutter or fire-shutter means equipped with a device to ensure immediate closing of such door, fire-door, shutter or fire-shutter after having been opened;

“separating element” means a wall or floor, which shall have a specific fire resistance, used between divisions, occupancies or tenancies in a building;

“septic tank” means a tank designed to receive sewage and to retain it for such a time and in such a manner as to secure adequate decomposition;

“service pipe” means any pipe which is part of a water installation and which is connected to any communication pipe;

“sewage” means waste water, soil water, industrial effluent and other liquid waste, either separately or in combination, but does not include stormwater;

“sewer” means a pipe or conduit which is the property of or is vested in the local authority and which is used or intended to be used for the conveyance of sewage;

“SHGC – solar heat gain coefficient” The ratio of the heat gain entering the space through the fenestration area to the incident solar radiation;

“single-stack system” means a particular one-pipe system in which trap vents are not required in terms of specific criteria set out in Part P;

“site” means any erf, lot, plot, stand or other piece of land on which a building has been, is being or is to be erected;

“sleeper wall” A masonry wall constructed to support a suspended ground floor;

“smoking area” Area which does not exceed 25 % of the total floor area of a public space and which is partitioned off with solid partitions;

“smoking room” A dedicated room where smoking is permitted;

“softwood timber” Timber derived from trees of the genus Pinus grown in Southern Africa and which has been appropriately graded with respect to its intended use;

“soil branch” means a branch discharge pipe which conveys soil water;

“soil fixture” means a sanitary fixture which receives and discharges soil water;

“soil pipe” means a discharge pipe which conveys soil water;

“soil water” means liquid containing excreta;

“sole plate” A strip of timber which is laid on top of walls to level the underside of flooring joists;

“space” A definable area, such as a room, toilet room, hall, assembly area, entrance, storage room, alcove, courtyard, or lobby;

“span” The distance between the centres of supports;

“spiral stairway” means any succession of tapered treads forming a curved stairway which extends as a single flight from one floor to another and which has a minimum radius of curvature of less than 100 mm;

“sprinkler system” means an approved system of piping and sprinkler heads connected to a water supply which when actuated by the effect of fire automatically releases water;

“stack vent” means a ventilating pipe connecting to a discharge stack above the highest connected discharge pipe;

“stairway” means any part of a building which provides a route of travel between different levels in such building and is formed by a single flight or by a combination of two or more flights and one or more intervening landings;

“storage tank” means any tank, other than any tank used for storage of hot water or any cistern serving a toilet pan or a urinal, which forms part of a water installation and is used for the storage of water;

“storey” means that part of a building which is situated between the top of any floor and the top of the floor next above it, or if there is no floor above it that portion between such floor and the ceiling above it (any open work floor, catwalk or gallery being taken to be part of the storey in which it is situated), and in relation to a building-

(a) the ground storey shall be taken as the storey in which there is situated an entrance to the building from the level of the adjoining ground or, if there is more than one such storey the lower or lowest of these;

(b) a basement shall be taken to be any part of the building which is below the level of the ground storey;

(c) an upper storey shall be taken to be any storey of the building which is above the level of the ground storey; and

(d) the height expressed in storeys shall be taken to be that number of storeys which includes all storeys other than a basement;

“stormwater” means water resulting from natural precipitation or accumulation and includes rainwater, surface water, subsoil water or spring water;

“stormwater drain” means a pipe, conduit or surface channel situated on a site, which is used to convey stormwater to a suitable point of discharge;

“stormwater sewer” means a pipe, conduit or channel, owned by or vested in the local authority, which is used for the conveyance of stormwater;

“street” means any street, road, thoroughfare, lane, footpath, sidewalk, sub- way or bridge which-

(a) is vested in the local authority; or

(b) the public has the right to use; or

(c) is shown on a general plan of a township filed in a deeds registry or a Surveyor-General’s office and has been provided or reserved for use by the public or the owners of erven in such township;

“street boundary” The boundary of a site which abuts any street;

“strip flooring” A floor that comprises strips of width not less than 35 mm and not more than 90 mm and that are tongued on the one edge and grooved on the opposite edge;

“structural” means relating to or forming part of any structural system;

“structural system” in relation to a building, means the system of constructional elements and components of any building which is provided to resist the loads acting upon it and to transfer such loads to the ground upon which the foundation of the building rests;

“structural wall” means a wall forming part of any structural system;

“stub stack” means a straight 100 mm diameter discharge stack not more than one storey high with a rodding eye at its top;

“suitable” means capable of fulfilling or having fulfilled the intended function or fit for its intended purpose;

“surface fire index” means a classification awarded to a combustible surfacing material (in excess of 1 mm in thickness) when tested in accordance with SANS 10177-3;

“suspended ceiling” means any ceiling supported on a system of hangers;

“suspended floor” A floor that spans supports;

 

T

Tapered treads National Building Regulations Glossary

 

 

 

“tactile” That can be perceived by using the sense of touch;

“tapered tread” means a tread which has a greater width at one side than at the other and a going which changes at a constant rate throughout its length;

“temporary building” means any building that is so declared by the owner and that is being used or is to be used for a specified purpose for a specified limited period of time, but does not include a builder’s shed;

“tenancy-separating element” A separating element between tenants within the same occupancy classification group;

“thatch” Reed, grass or straw used in roof construction;

“the Act” means the National Building Regulations and Building Standards Act, 1977 (Act No. 103 of 1977);

“tie beam” – bottom chord. The horizontal or inclined member that establishes the lower edge of a truss;

“total R-value” The sum of the R-values of the individual component layers in a composite element, including the air space and associated surface resistances measured in m2·K/W;

“total U-value” The thermal transmittance (W/m2·K) of the composite element, including the air space and associated surface emittance;

“toughened glass” means a glass produced by subjecting annealed glass to a process of heating and rapid cooling which produces high compression in the surface and compensating tension in the interior;

“trained plumber” means any person who in the trade of plumbing has, in terms of the Manpower Training Act, 1981 (Act No. 56 of 1981), passed a qualifying trade test or has been issued with a certificate of proficiency, or has obtained a National Certificate in Construction Plumbing, National Qualification Framework Level 3;

“transfer space” The space required by a wheelchair user to transfer to or from a vehicle, toilet or seat;

“transparent glazing” Glazing through which images can be clearly seen;

“trap” means a pipe fitting or a part of a sanitary fixture which is designed to retain a water seal;

“trap vent” means a ventilating pipe connecting an individual trap to the open air or to another ventilating pipe;

“travel distance” means -

(a) the distance, in any building where emergency routes are required, from the furthest point in any room in such building to an access door; or

(b) where no emergency routes are required, the distance from the furthest point in any room in a building to an escape door;

“tread” means the upper surface of a step;

“truss” The triangulated combination of members and joints which, when fitted together, form a rigid structural component capable of withstanding loads;

“turning space” The circulation space in which a wheelchair can turn through 360°;

“two-pipe system” means a system of piping between sanitary fixtures and a drain in which waste water and soil water discharge through separate discharge pipes and in which any trap venting or other venting that is required is via separate ventilating pipes for the waste and soil water systems;

 

U

Unit fire load National Building Regulations Glossary

 

 

 

“underlay” The flexible membrane fitted between the roof support structure and the battens;

“unit fire load” means the fire load of a compartment or division divided by the floor area of such compartment or division, and is expressed either as timber equivalent (kg/sq m) or heat energy value per sq m (MJ/sq m);

“unprotected steel” means structural steel which is not protected with fire resistant material against the effect of fire;

 

V

Vent Pipe s National Building Regulations Glossary

 

 

 

“vent” means a ventilating pipe;

“ventilated improved pit toilet” – VIP toilet A toilet which comprises

  1. a)  a pit into which the excreta fall and from which the liquid fraction seeps into the surrounding ground;
  2. b)  a slab which covers the pit and which has two holes, one for the excreta to fall through and one for the vent pipe;
  3. c)  a superstructure which provides privacy and which prevents light from entering the pit;
  4. d)  a pedestal seat and seat cover;
  5. e)  a vent pipe which removes odour from the pit; and
  6. f)  a fly screen at the top of the vent pipe which prevents flies from entering the pit through the pipe and prevents flies that have entered the pit through the pedestal from leaving through the vent pipe;

“ventilating pipe” means a pipe which leads to the open air at its highest point and which provides ventilation throughout a drainage installation for the purpose of preventing the destruction of water seals, but does not include a discharge pipe;

“vent stack” means a main vertical ventilating pipe of any part of a drainage installation;

“vent valve” means a one-way air valve specifically designed and constructed to be fitted near the crown of the trap serving a waste fixture to protect the water seal of such trap against excessive negative air pressure arising in the fixture discharge pipe;

“vertical” in relation to a discharge pipe or ventilating pipe, means inclined at 45° or more to the horizontal, and in relation to a glass pane means installed at any angle between 60° and 90° to the horizontal, both figures being inclusive;

 

W

Water fitting National Building Regulations Glossary

 

 

 

“waste branch” means a branch discharge pipe which conveys waste water only;

“waste fixture” means a sanitary fixture from which waste water is discharged;

“waste pipe” means a discharge pipe which conveys waste water only;

“waste water” means used water not contaminated by soil water or industrial effluent and shall not include stormwater;

“water fitting” means any component, other than a pipe, of any water installation, through which water passes or in which it is stored;

“water installation” means an installation used or intended to be used for the conveyance or storage of water in any building or on any site on which such building is situated and includes any pipe or any water fitting other than any water meter vested in the local authority;

“water seal” means the water in a trap which acts as a barrier against the flow of any foul air or gas;

“water supply system” means any system of structures, aqueducts, pipes, valves, pumps, meters or other appurtenances relating thereto which are vested in the local authority and are used or intended to be used by it in connection with the supply of water;

“web” The member that joins the top chords and bottom chords to form triangular patterns that give truss action;

“wheelchair-accessible toilet” A toilet designed to include use by wheelchair users;

“wind load” means the force exerted by the action of wind;

“winder” means any tapered tread that has a minimum going of less than 50 mm and which is used in conjunction with non-tapered treads in a single flight;

“wired glass” means annealed glass containing a wire mesh which is completely embedded in the body of the glass during manufacture;

 

Z

Zone of space494 National Building Regulations Glossary

 

 

 

“zone of space” in relation to an opening in an external wall or a portion of such an opening, means a volume of open air outside such opening.

Apr 032013
 

Stormwater Disposal – What the Regulations Say

stormwater 1 Stormwater Disposal

When the heavens open up and flood gardens and roads, you rely on storm water drains to deal with the excess water.

stormwater 2 Stormwater Disposal

The house on the far side of the road was totally flooded during a major downpour. The question is, whether the house was built with sufficient drainage to be able cope with all the storm water.

Property owners are responsible for the removal of storm water from their property. They may NOT simply discharge excess water onto adjacent land or into the street unless this is permitted by neighbors and/or the local council or municipality.

SANS 10400: Part R Stormwater Disposal

The law is very clear on the issue of storm water disposal, although sites used exclusively for “dwelling houses” are not as carefully controlled as larger buildings.

Note that a dwelling house is (in terms of the legislation) a single dwelling unit and any garage and other domestic outbuildings that are situated on the site. A dwelling unit contains one or more habitable rooms and it provided with both cooking facilities and adequate sanitary facilities.

Part R of the law states: “The owner of any site shall provide suitable means for the control and disposal of accumulated stormwater which may run off from any earthworks, building or paving.”

The legislation also states that the “means of stormwater disposal” used may be addition to, or in combination with any drainage that may be required in terms of F4(2). SANS 10400: Part F Site Operations is described in more detail in the section on site operations which you will find HERE. The relevant section – 4(2) – is also discussed below.

These legal requirements will be “deemed to be satisfied” if the stormwater is provided in accordance with SANS 10400-R (the SANS drawn up by the SABS for “The application of the National Building Relations”, Part R), which is available from the SABS (- CLICK HERE -)  for R147 + VAT.

The SANS deals with all types of storm water disposal, including rain water from gutters, downpipes, roofs, and paving, and any other excess water that may accumulate on the property.

In addition, the legislation states that it is the right of the local authority to demand that storm water disposal is provided in accordance with “an acceptable rational design prepared by an approved competent person” (the concept of a competent person is discussed in some detail on our sister site, ownerbuilding.co.za – CLICK HERE for the link to the relevant article). So if your local authority is of the opinion that a qualified person should design a stormwater system for your property they must notify you (or the owner of the property) and explain their reasons in writing, and demand that plans and particulars of “a complete stormwater control and disposal installation” for the site and any buildings on it, are submitted for approval.

The law also states that the regulations should not be interpreted specifically as requiring roof gutters and downpipes if another suitable means of drainage has been provided to remove or disperse rainwater from the roof of the building. There are alternatives that architects sometimes prefer.

Ultimately, all drainage must  be shown on plans submitted to the local authority, and it is up to the local authority to decide whether these are suitable and adequate for each individual site.

SANS 10400: Part F Site Operations F4(2)

Part F4 deals with preparation of a site that is to be built on. Point (2) states that when a building is to be erected on a site that is waterlogged or saturated with water, or where any building is going to be situated so that water will drain naturally towards it, drainage must be provided to direct the water away from the site or building, to a storm water drain, or somewhere that it can be disposed of in some other safe and approved manner.

SANS 10400: Part L Roofs

This part of SANS 10400 is dealt with elsewhere on this site – CLICK HERE for the link.

Waterproofing and runoff are dealt with in some detail in the relevant SANS for The application of the National Building Regulations.

Other SANS that deal with Stormwater Drainage

Additional SANS that deal with storm water drains and gullies are intended for the use of civil engineering construction and include:

  • SANS 1200 LE – Standardized specification for civil engineering construction Section LE: Stormwater drainage.

This is a drawing from the above SANS that shows how a precast concrete manhole for storm water should be built.Manhole Stormwater DisposalManhole dimensions Stormwater Disposal

  • SANS 10120 – A Code of practice for use with the above, including:
  1. Part 2: Project specification Section LE: Stormwater drainage
  2. Part 3: Guidance for design Section LE: Stormwater drainage
  3. Part 4: Typical schedule of quantities Section LE: Stormwater drainage
  4. Part 5: Contract administration Section LE: Stormwater drainage

 

 

Mar 272013
 

Rapid Urban Decay in Jozi Blamed on Illegal Building

Urban Johannesburg s Illegal Building Leads to ChaosThe City of Johannesburg has lost control of town-planning infringements, according to an article published in The Star newspaper at the beginning of February 2013. It seems they simply can’t stop them from happening.

The Accusations

In the article, Ros Greeff, the City’s member of the mayoral committee responsible for development planning and urban infrastructure, said that procedures were slow and not working. As a result, she claimed, they were leading to the rapid decay of many areas across the city.

This all came to public attention at a public meeting in Cyrildene (one of Johannesburg’s “better” suburbs) where angry residents voiced their concerns at the burgeoning number of building transgressions that have been occurring in the area. According to Ms Greeff, property owners are totally disregarding instructions, including court orders, that are issued by the local authority to stop illegal construction.

According to the article, the main concern in this part of the City is the building of additional rooms around residential properties intended to temporarily accommodate Chinese people moving into the country. The structures generally don’t comply with South African national building standards (SANS); but worse, they don’t adhere to proper health, sanitary or fire conditions either, and they inevitably cause overcrowding.

Both residents and ward councillors say that the City of Johannesburg has done absolutely nothing to stop this. They also maintain that telephone calls and emails that have logged many complaints get no response at all.

The current ward councillor for Cyrildene and Bruma, Alison van der Molen, maintains that in her ward alone, 1 200 transgressions of this type have been logged. She has stated  on record that not one of these has been acknowledged, and none have been acted upon.

She was quoted in The Star article as saying: “There are some old cases against illegal building going on in this area which date back to 2006 and which are still stuck in the legal system somewhere.”

The scary part is that in terms of the Municipal Systems Finance Act, the City’s council is obliged to provide feedback to all the complaints of residents. And this is clearly not being done.

Van der Molen says that residents and ward councillors have simply been ignored by the town planning department.

According to Rob Crawford from the local community policing forum, there have been no prosecutions or demolitions, and absolutely no visible signs of action that would discourage this type of lawlessness.

“Some of our complaints go back five years,” he told The Star. “No-one cuts illegal connections. People add rooms as they please, causing overcrowding and health issues.”

Councillor Carlo da Rochas, whose ward includes parts of Bez Valley, Kensington, Bertrams and Observatory, concurs. He maintains that entire “villages” are springing up in backyards in his ward. As a result he regularly sends photos, reports and e-mails to the town planning department, but never gets a response.

“Town planning has lost control over our wards. I have illegal businesses in almost every block in my ward. Neighbours are losing money in their investments and the council, therefore, loses out on revenue.”

Ronaldo Sorban of the Observatory Residents’ Association said that the blight was spreading to his area as well, and yet again, he claimed that no-one was listening to complaints.

“The rot has to stop.”

It’s not all bad though. According to Ros Greef positive things have already been achieved in Cyrildene. For instance, a survey has been conducted and out of 85 properties visited, 32 transgressions were found, 27 of which were illegal accommodation establishments. Of these 22 have been handed over to attorneys for legal action, and two court orders have already been issued. That’s really GOOD news.

But, she says: “The by-laws are not tough enough and the city has not been proactive enough. Even when we are alerted immediately at the start of building operations, and we issue stop orders, we are ignored, and once they have put a roof on the structure… we can no longer evict as the high court has ruled that we then have to find the occupants alternative accommodation.”

Action to be Taken

The mayor of the City of Johannesburg, Parks Tau has asked Ms Greeff to put together a new task team to specifically address this issue.

“We are looking at solutions which will include immediate demolition by JMPD, transferring the matter from the high court to the magistrate’s courts, reintroducing fines, and involving the SAPS and laying of criminal charges.”

We wish her luck and success in her endeavours.

Mar 112013
 

Fenestration and Glazing Guidelines, Procedures and Calculations.

Windows house335 Fenestration Calculations

The guidelines featured in the pdf below give an idea to anyone wanting to calculate the Fenestration Compliance Procedures in terms of Sans 10400-XA:2011 and SANS 204:2011, what is required and what is involved.

There is a step-by-step guide to area (nett floor) calculation with reference to the parts of the regulations that apply. A SGHC (solar heat gain calculator) is also supplied, to calculate the heat conducted in and out of a building. There are a couple of “real life” calculations at the end of the document that illustrate how this was achieved.

You will see that the calculations that need to be done to comply with the Regulations are not at all straightforward. But you do, in any case require a “competent person” to draw up your building plans, submit them to the local authority, and take responsibility for the project (including ensuring that construction is in accordance with the plans). A competent person should be well equipped to interpret fenestration and glazing guidelines as well as procedures and the calculations. If not, it is the responsibility of that person to include someone who is in the project.

Download (PDF, 250KB)

Mar 052013
 

The NHBRC – Frequently Asked Questions and Answers

Houses 510 NHBRC   Q&As

 

The NHBRC has a page with a number of questions that we also get on this website. The most common questions and answers we have listed here below with thanks to the NHBRC.  We must point out to all home owners and potential home owners, as well as all contractors and home builders, that the home being built has to be registered with the NHBRC. The builder or contractor also has to be registered with the NHBRC. The NHBRC will not consider a claim or complaint if this is not done. If the house or contractor have not registered then they have broken the law and might be liable to a fine. There are links to the NHBRC site at the end of the Q&A’s where you will find more answers.

 

Q - How Does One Know Whether A Builder Is Registered With The NHBRC?

A - The NHBRC has established customer centers in all provinces. To find out if a builder is registered with the NHBRC you can contact your nearest customer center, search online or by calling the toll free number 0800200824.

 

Q - Does The NHBRC Conduct Inspections?

A - Every new house constructed must be inspected. If the house is enrolled prior to construction, the NHBRC is afforded the opportunity to carry out all necessary inspections. The number of inspections conducted per house is a function of the size and the complexity of the design of the house.

 

Q - What Does The NHBRC Inspect?

A - The following inspections are carried out:

Foundations
Roof height
Practical completion
Stormwater
Carpentry
Plumbing
Electrical
And waterproofing

 

Q - How Many Inspections Are Carried Out By The NHBRC In The Building Process Up To Completion Of A House?

A - A minimum of four inspections are carried out to ensure that the house is of good quality and that it will be fit for habitation. Housing consumers and home builders are encouraged to demand an inspection from the NHBRC during construction.

 

Q - How Does The NHBRC Handle Complaints?

A - The NHBRC has established complaint handling mechanisms, which have assisted many housing consumers. Each complaint is professionally and speedily processed on behalf of the housing consumer. According to our records the NHBRC has not failed any housing consumer who had a genuine structural defect. All home owners, public and private institutions and media houses are advised to send all the complaints received by it to the NHBRC for evaluation.

 

Q - What Should a Home Owner Do When There Is a Problem with a Builder’s Work?

A - The housing consumer (home owner) should contact the home builder within three to seven days. The housing consumer can approach the NHBRC if the home builder fails to attend to the problem.

 

Q - Under What Circumstances Will The NHBRC Do Remedial Work To My House?

A - The NHBRC is responsible for repair of major structural defects which occur to an enrolled home.  The process is initiated once it is established that the home builder is either liquidated, unwilling or is unable to undertake remedial works. When the homebuilder disputes the findings and recommendations in the conciliation report or the recommendation of a competent person (Engineer), the NHBRC will assist the housing consumer by undertaking remedial work.

 

Q - What Happens If Major Structural Defects Arise Within The First Five Years Of Occupation?

A - The NHBRC’s fund for rectification covers a home which includes:

Private drainage system from the structure up to the municipal connection or the cesspit connection
Any garage or storeroom
Any permanent outbuilding designed for residential purposes
Any retaining wall
In the case of sectional title unit, it includes the common property in terms of the sectional Titles Act.

 

There are more Answers on the NHBRC site.

Mar 052013
 

Regulations for Lightning Conductors on Thatch Roofs

Thatch house lightning Thatch Roofs and Lightning

Thatch roofs are most susceptible to be set alight by lightning than any other roof type. For the protection of the public and property the South African National Standard 62305-3 was introduced in 2011.

SANS 62305-3: Protection against Lightning (published in 2011) is drawn from an international standard, IEC 62305. Part 3 deals with “physical damage to structures and life hazard”.

Remember that anything related to electrics must be dealt with by a qualified and registered electrician.

Introduction to the Regulations for Thatch Roofs and Lightning

This part of IEC 62305 deals with the protection, in and around a structure, against physical damage and injury to living beings due to touch and step voltages.

The main and most effective measure for protection of thatch structures against physical damage is considered to be the lightning protection system (LPS). This usually consists of both external and internal lightning protection systems.

An external LPS is intended to:

  1. intercept a lightning flash to the structure (with an air-termination system),
  2. conduct the lightning current safely towards earth (using a down-conductor system),
  3. disperse the lightning current into the earth (using an earth-termination system).

An internal LPS prevents dangerous sparking within the structure using either equipotential bonding or a separation distance (and electrical insulation) between the external LPS components and other electrically conducting elements internal to the structure.

The main protection measures against injury to living beings due to touch and step voltages are intended to reduce the:

  1. dangerous current flowing through bodies by insulating exposed conductive parts, and/or by increasing the surface soil resistivity,
  2. occurrence of dangerous touch and step voltages by physical restrictions and/or warning notices.

The type and location of an LPS should be carefully considered in the initial design of a new structure, thereby enabling maximum advantage to be taken of the electrically conductive parts of the structure. By doing so, design and construction of an integrated installation is made easier, the overall aesthetic aspects can be improved, and the effectiveness of the LPS can be increased at minimum cost and effort.

Once construction work on a site has started, access to the ground and the proper use of foundation steelwork for the purpose of forming an effective earth-termination, may well be impossible. Therefore, soil resistivity and the nature of the earth should be considered at the earliest possible stage of a project. This information is fundamental to the design of an earth-termination system and may influence the foundation design work for the structure.

Regular consultation between LPS designers and installers, architects and builders is essential in order to achieve the best result at minimum cost.

If lightning protection is to be added to an existing structure, every effort should be made to ensure that it conforms to the principles of SANS 62305-3. The design of the type and location of an LPS should take into account the features of the existing structure.

Notations

NOTE 1

Specific requirements for an LPS in structures dangerous to their surroundings due to the risk of explosion are under consideration. Additional information is provided in Annex D for use in the interim.

NOTE 2

This part of IEC 62305 is not intended to provide protection against failures of electrical and electronic systems due to overvoltages. Specific requirements for such cases are provided in IEC 62305-4.

NOTE 3

Specific requirements for protection against lightning of wind turbines are reported in IEC 61400-24 [2].

References

The following referenced documents are indispensable for the application of this national standard. These references are listed in the standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

IEC 60079-10-1:2008, Explosive atmospheres – Part 10-1: Classification of areas – Explosive gas atmospheres

IEC 60079-10-2:2009, Explosive atmospheres – Part 10-2: Classification of areas – Combustible dust atmospheres

IEC 60079-14:2007, Explosive atmospheres – Part 14: Electrical installations design, selection and erection

IEC 61557-4, Electrical safety in low-voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. – Equipment for testing, measuring or monitoring of protective measures – Part 4: Resistance of earth connection and equipotential bonding

IEC 61643-1, Low-voltage surge protective devices – Part 1: Surge protective devices connected to low-voltage power distribution systems – Requirements and tests

IEC 61643-21, Low-voltage surge protective devices – Part 21: Surge protective devices connected to telecommunications and signalling networks – Performance requirements and testing methods

IEC 62305-1, Protection against lightning – Part 1: General principles IEC 62305-2, Protection against lightning – Part 2: Risk management

Feb 152013
 

Proven Ways of Waterproofing Roofs

Waterproofing roofs is perhaps the most important factor when it comes to roof construction.

Flat Roof 435 Waterproofing Roofs

It is vital that roofs are correctly waterproofed, especially when they are “flat”.

The National Building Regulations and Building Standards Act states that roofs must be designed and constructed safely so that they are not damaged by wind or any other natural force. The law also states that they must be waterproof, specifically:

  • Roofs must be durable and must not allow the penetration of rainwater or any other surface water to its interior.
  • Roofs must not allow the accumulation of any water on its surface.

But the legislation simply lays down the basics. For additional guidance, anyone building needs to refer to the South African National Standard that explains how the law can be successfully applied.

In terms of waterproofing, the Standard, The application of the National Building Regulations Part L-Roofs specifically covers:

  • Roof coverings and waterproofing systems, and
  • Drainage and waterproofing of flat roofs.

Roof Coverings and Waterproofing Systems

The SANS elaborates on the legislation stating that roofs must be able to resist penetration of rain to the extent that water in category 1 buildings (see below) any water that penetrates the roof won’t run down the inside face of walls onto the floor, or form damp patches on the ceiling or the floor. In terms of all other buildings (i.e. those that are not category 1), if water penetrates the roof it won’t be intense enough to run down the inside surface of the roof or drip onto the floor or ceiling.

The SANS also state that roof coverings and waterproofing systems must be capable of being repaired if damaged, even if the materials are old.

In addition, roof coverings must be able to resist:

  • temperatures from -10 degrees C to +80 degrees C, as well as quick changes of temperature, without deteriorating
  • the effect UV radiation, without deterioration
  • effects of condensation under the surface
  • chemical attack from basic salt or gas in the atmosphere
  • growth of bacteria, fungi, lichens and so on
  • any penetration or puncturing while the roof is in use
  • movement of the roof structure

All products that are used for roof coverings and waterproofing systems must have a lifespan of at least 10 years. If the structure or system is particularly intricate, making it difficult to replace, then the expectation is that materials used should have a lifespan of at least 20 years.

So what is a category 1 building?

Part A: Administration of SANS 10400 classifies all buildings in terms of occupancy (which in terms of the law means “the particular use or the type of use to which a building or portion thereof is normally put or intended to be put”.

A category 1 building falls into various legislated “classes” namely:

  • A3 – places of instruction,
  • A4 – places of worship,
  • F2 – small shops,
  • G1 – offices,
  • H2 – dormitories where groups of people are accommodated in single rooms,
  • H3 – domestic residences that consist of two or more dwelling units on one single site,
  • H4 – dwelling houses where there is just one dwelling unit (or house) on the site, and possibly also a garage and domestic outbuildings. This is, of course, your most common “home”.

A category 1 building also has no basements, a floor area that is no larger than 80 square metres, and a maximum length of 6 m between intersecting walls or members that provide lateral support. So you will see that there are quite a lot of South African homes that don’t fall into the 1 category.

 Roof Coverings in Pitched Roofs

The SANS have useful standards that we have adapted for ease of reference. The three below specify:

  1. The minimum roof slopes of sheeted roofs
  2. The minimum roof slopes of non-sheeted roofs
  3. The minimum thickness of thatch layers

    Min slope sheeted Waterproofing Roofs

    Table 1: The minimum roof slopes of sheeted roofs

Min slope non sheeted Waterproofing Roofs

Table 2: The minimum roof slopes of non-sheeted roofs

If metal roof tiles are used on an existing roof of this category, the existing slope may be retained. But is is important to be aware that if there are strong gusts of wind, the suction force on the roof tiles might exceed the mass of the tiles. If the tiles are securely fixed it will usually prevent them from being lifted. But a much better option is to include an underlay membrane under the slates or tiles. This will reduce the risk of wind uplift because it can lower these pressures substantially.

Thatch Waterproofing Roofs

Table 3: The minimum thickness of thatch layers

NOTE: SANS 10062 contains fixing instructions for the fixing of different types of roofing. This national standard is available from the SABS.

The pitch indicated in Tables 1 and 2 are minimums. In addition to these, sheeted roofs in category 1 buildings that don’t have hips and valleys, may have a slope of 5 degrees, as long as all the end laps are sealed and have a lap of at least 250 mm. The slope of any valleys in the roof should then be no less than 11 degrees.

If tiles are laid at a pitch of 30 degrees they must (in terms of the SANS) be tested in a rig as specified in SANS 542. The relative humidity must be maintained at a minimum of 70% during the test, and droplets should not form on the underside of the roof. It is a little different for category 1 buildings – rather than droplets forming (or rather not forming) – the test must show that water doesn’t flow down the inside of the tiles. In other words the roof MUST be waterproof!

Sheeted roofs should be tested in accordance with ASTM E 1646 to check that they don’t leak. There must be no dripping of water onto the ceiling or floor of category 1 buildings.

All tiled and sheeted roof coverings must be installed in accordance with the manufacturer’s instructions and/or by workers with the correct skills.

Thatched roofs should be installed according to SANS 10407. The required thickness of the thatch is shown in Table 3 (above).

All roofs with a pitch less than 26 degrees or more than 45 degrees, and all roofs in coastal areas (to a distance of 30 km from the sea) should have an undertile membrane that is loose-laid so that water can drain between the rafters. If an undertile membrane is properly laid it will provide a very effective, impermeable barrier against wind-driven rain and dust. For this reason the SANS states that underlays should be provided for all slate and tiled roofs, no matter what the pitch (or slope), and where ceilings are not installed.

The manufacturers’ instructions must be followed carefully for tiles, slates and shingles.

Roof Lights

waterproof skylight205 Waterproofing Roofs

A well designed, waterproof roof light.

Roof lights have become increasingly popular over the past few decades; but if they are not properly designed and installed, they can leak.

The SANS for roofs state that any roof lights may have an opening of no more than 0.6 square metres. If it is the type that incorporates a translucent roof sheet, it may be 700 mm wide. In addition, roof lights must be able to resist UV degradation for at least 15 years, and hail (at any time) of 10 J (in accordance with SANS 10400-B).

Lastly, all roof lights must be designed and installed in a way that rain will not penetrate the roof.

Drainage and Waterproofing of Flat Roofs

Flat roofs can be extremely difficult to waterproof, which is why all so-called “flat” roofs should be built with a fall of 1:80. This might require a steeper design slope of 1:50 in concrete slabs where construction is not always 100% accurate. A 1:50 slope is also required where there is an interruption in the flow of water on the roof.

The slope should be towards external gutters, roof edges and outlets. Other factors that should be considered include:

  • an avoidance of “penetrations” through the roof, or they should be at least 200 mm away from vertical surfaces like walls and “upstand” beams
  • an avoidance of having clusters of plumbing pipes, air conditioning pipes, and electrical conduit 
  • formation of a suitable step between inside and outside areas to prevent water flowing or dripping into the interior of the house or other building

It is very important that precast panels and precast roof structures are designed in a way that if there is subsequent movement of the concrete elements, this will not damage the waterproofing system or compromise its performance.

The SANS has a really useful drawing that shows how construction drawings should clearly designate ridges and valleys, and indicate the relative fall – or slope.

Gutters and Downpipes

Gutters and downpipes are not mandatory. However, unless gutters are designed by a competent person, they may only be located on the “perimeter” of the building. They should also be designed to ensure that stormwater doesn’t penetrate the inside of any building if they become blocked at any stage.

Rain chains Waterproofing Roofs

Rain chains are a popular option to gutters

Outlets must be set flush with concrete. If there is timber decking they must be recessed so that there isn’t any ponding around the outlets. Any outlets should be at least 500 mm from upstand elements including parapet walls, and they should be at least one metre from any expansion joints.

Intallation requirements of manufacturers and suppliers of rainwater goods absolutely must be adhered to. 

Flat Concrete Roofs

Any concrete roof design should take the thermal properties of concrete into account. This will be determined by a concrete technologist or other competent person, who will determine the required thickness of the concrete and its density, and design the roof in such a way that a waterproofing layer is built up. Often the designer will incorporate a “thermally insulating layer” above the structural concrete deck. When this is done it is important that attention is given to ventilation so that any moist air that might accumulate below the waterproofing layer is vented to the outside.

The concrete used for flat roofs shouldn’t contain more than 7% moisture by weight; and sand-cement or lightweight screeds shouldn’t contain more than 10% moisture by weight.

If expansion joints to accommodate the flow of water are not custom-designed by a competent person, “twin kern upstand-type joints” should be installed over any expansion joints. These should be positioned away from any outlets, and should be built in accordance with the illustration given in SANS 10400-L. Upstand beams that are at least 170 mm high should be incorporated where masonry walls meet the concrete surface of the roof. At these “intersections” (i.e. where they join) corner fillets measuring at least 75 mm (vertically and horizontally) should be build in.  There is another drawing in the SANS that shows how this should be done. Another drawing shows how drips should be incorporated under all overhangs of concrete roofs.

In addition to these design elements, all concrete and screened roof surfaces must be waterproofed and constructed to the correct falls and cross falls (see first paragraph under Drainage and Waterproofing of Flat Roofs above and the relevant section in the SANS). It is vital that there are no undulations in the concrete surface, and nothing should be allowed to protrude into the concrete or contaminate it.

The recommended finish for concrete roofs is wood floating. While the final surface should be sound and smooth, concrete and screened surfaces should not be highly polished. So they should NOT be power floated.

Waterproofing Systems

Any waterproofing system that is installed on flat roofs MUST be done by a “competent person” who MUST follow the manufacturer’s instructions. SANS 10400-L states that for roofs to be up to standard, they must remain watertight for at least five years without the need for any form of maintenance other than the normal cleaning of downpipes, gutters and so on. It is also important that the person doing the installation is satisfied that the materials used are appropriate for that particular application, and should therefore take into account:

  • the degree of exposure the waterproofing system will be subjected to
  • how much protection the waterproofing material will have
  • and ultimately whatever affects the building because of where it is located

It is important to realize that waterproofing systems can delaminate if the substrates don’t allow any moisture vapor that has been trapped to escape. Generally a sand-cement screed that is not very dense will allow retained moisture vapor to dissipate and therefore protect against the possibility of delamination.

SANS 10400-L suggests that a 20 mm screed is laid over all “lightweight” screeds, because these are generally too friable and porous to provide good adhesion for waterproofing systems. The SANS also suggests that concrete and screened roof surfaces be allowed to dry thoroughly before any type of waterproofing system is applied.

Where waterproofing turnups are provided against brickwork and other masonry walls, they should be counter-flashed if they are not linked to the stepped damp-proof courses in cavity walls. The same membrane should be used, and the flashing should be cut into walls to a depth of at least 40 mm.

Generally sand-cement coves with a radius of at least 45 mm should be formed at all the inside corners of both vertical and horizontal surfaces – unless a particular waterproofing system has a different design and doesn’t require this. Where there is a timber deck, 38 mm timber fillets may be fixed at all the junctions of horizontal and vertical surfaces.

There is always a potential problem with outlets. The installer must therefore pay close attention to overflow pipes, flues and so on, and make sure that the waterproofing material used covers everything but the opening. Generally waterproofing membranes around any pipe work should be clamped with a hose clamp or something similar, before flashing is applied over the pipe.

If outlets aren’t the “full-bore”, coned type, pipes should be flanged so that waterproofing can be done correctly. Elements such as water storage tanks and solar absorbers should never be allowed to penetrate the waterproof layer.

All external corners and edges to be waterproofed should be rounded, and the height of all DPCs should be at the same level as the waterproofing turnups.

In addition to this part of SANS 10400, SANS 10021 also provides some information and guidance about the waterproofing of roofs. Remember, it’s important to do it correctly!