If you are building or extending a home in South Africa, your roof has to comply with the National Building Regulations before the municipality will issue an occupancy certificate. For roof trusses that means a design that meets SANS 10400-L, manufacture to SANS 10243, and an engineer who takes responsibility for the roof.
This guide explains, in plain language, what the rules are, who is responsible for what, and what paperwork you need at the end.
This is a general guide for homeowners and builders, not legal or engineering advice. Your appointed engineer and your local municipality have the final say on your project.
The standards that apply to roof trusses
SANS 10400-L: Roofs
SANS 10400 is the standard that explains how to meet the National Building Regulations. Part L covers roofs. Regulation L3 states that a roof is deemed to satisfy the regulations if it complies with SANS 10400-L. Among other things, Part L sets out:
- maximum truss spacing for different roof coverings,
- allowable roof pitches for tiles and sheeting,
- how trusses must be anchored to the walls,
- bracing requirements,
- minimum timber grades and treatment.
Part L also includes “deemed-to-satisfy” details for simple site-made roofs. Anything outside those limits, including factory-made engineered trusses, must be designed by a competent person.
SANS 10243: Manufacture and erection of timber trusses
SANS 10243 covers the manufacture and erection of timber roof trusses. It deals with how trusses are designed, made, handled, erected and braced, and the competence of the people doing it.
SANS 10082: Timber buildings
SANS 10082 covers timber-frame buildings and is relevant where the structure goes beyond a conventional masonry house with a timber roof.
Who is responsible for the roof?
The competent person (engineer)
For an engineered roof, the municipality requires a competent person to take responsibility for the design. This is normally a professional engineer or professional engineering technologist registered with ECSA. They are appointed on Form 2 when plans are submitted and confirm completion on Form 4 at the end.
On many houses, the engineer appointed for the structure also takes responsibility for the timber roof. City of Cape Town guidance gives the example of a double-storey house where the engineer designing the floor slabs is also responsible for making sure the timber roof trusses are correctly designed.
The truss manufacturer
The manufacturer designs the individual trusses, usually on specialised software, and makes them in a factory to SANS 10243. Reputable fabricators are audited annually by the Institute for Timber Construction South Africa (ITC-SA).
The erector or builder
The roof must be erected, braced and fixed exactly as designed. Most roof failures we see come from site errors: missing bracing, trusses not tied down, or members cut to fit services.
What is ITC-SA and why does it matter?
The Institute for Timber Construction South Africa is the industry body for engineered timber roofs. It audits truss fabricators and issues an annual certificate of competence to those that meet its requirements. Choosing an ITC-SA approved fabricator gives you, your engineer and the municipality confidence that the trusses were designed and made properly.
All six Truss Master plants are ITC-SA approved, and every roof is designed on MiTek software.
What compliant roof trusses look like on site
When the trusses arrive and go up, you or your engineer can check for these signs of a compliant roof:
- Graded timber. Structural timber should carry a visible grade stamp. SANS 10400-L calls for at least grade 5 softwood.
- Treated timber where needed. Coastal and termite-prone areas need preservative-treated timber.
- Correct nail plates. Each joint should have a properly sized, fully embedded galvanised plate.
- Layout and bracing drawings. The supplier should provide a roof layout and bracing details.
- Correct spacing. Trusses at no more than the designed centres, for example 760 mm for tiled roofs under the deemed-to-satisfy rules.
- Anchoring. Each truss tied down to the walls with galvanised straps or wires built into the brickwork.
- Bracing installed. Top chord and bottom chord bracing fitted as shown on the drawings.
Our guide to truss spacing, pitch and bracing covers these items in more detail.
The paperwork you need
- Approved building plans showing the roof.
- Form 2: appointment of the competent person for the structure, including the roof.
- Truss design documents: layout drawings, truss designs and bracing details from the manufacturer.
- Roof inspection: the engineer, or a competent inspector, checks the erected roof before the ceilings close it up.
- Form 4: the engineer’s completion certificate, submitted to the municipality.
- Occupancy certificate: issued by the municipality once all the required certificates are in.
Requirements and form names can vary slightly between municipalities, so confirm the details with your engineer and your local building control office.
Common reasons roofs fail inspection
- Bracing missing or incomplete.
- Trusses not tied down to the walls.
- Webs cut to make space for geysers or ducts.
- Extra loads added later, such as solar panels or water tanks, without a design check.
- Trusses spaced further apart than designed.
- Untreated or ungraded timber used for repairs or extensions.
Frequently asked questions
Do roof trusses need an engineer in South Africa?
For engineered roof trusses, yes. A competent person, usually a registered professional engineer or technologist, must take responsibility for the roof design and sign it off at completion.
What is a roof truss certificate?
People often use this term for the engineer’s sign-off that the roof was designed and built correctly. It forms part of the completion documents the municipality needs before issuing an occupancy certificate.
Can I build my own roof trusses on site?
SANS 10400-L includes deemed-to-satisfy rules for simple site-made Howe trusses within set span limits. Anything outside those limits must be designed by a competent person. Factory-made engineered trusses are usually faster, use less timber and come with the design documents you need.
Does the roof need to be inspected before the ceiling goes in?
It should be. Once the ceilings are closed, bracing and fixings are hard to inspect. Arrange the inspection with your engineer before the ceiling contractor starts.
Does adding solar panels affect my roof compliance?
It can. Panels add weight and wind load. Have the roof checked before installation, and tell your truss designer upfront if solar is planned.
Build a roof that passes first time
Truss Master designs every roof on MiTek software and manufactures at ITC-SA approved plants, with the drawings your engineer needs for sign-off. Send your plans to your nearest branch for a free quote and roof design, or read our roof truss price guide first.
