SANS 10400-K is the walls Part. It gives prescriptive panel-size tables for single-leaf, cavity, collar-jointed and hollow masonry walls in single and double-storey buildings, plus rules for free-standing and retaining walls, lintels, the damp-proof course and fire behaviour. SANS is the South African National Standard, published by the SABS, the South African Bureau of Standards, under the National Building Regulations and Building Standards Act 103 of 1977 (the NBR, or the Act). The brief works from SANS 10400-K:2011 (Edition 3), which supersedes the walls sections of the older SABS 0400:1990.
A plain caveat first. The panel sizes, mortar and unit strengths and tie specifications below come from public summaries of the paywalled SABS SANS 10400-K text and from the gazetted regulations. They are an orientation, not a compliance spec, and the brief reproduces only two of the alternative panel combinations from each table. Confirm the exact current values, the full tables and any interpolation rules with your local authority and the SABS SANS 10400-K text before you build or submit plans.
What this Part covers
Part K is the deemed-to-satisfy rule book for masonry walls. It tells you, without an engineer, how big a wall panel can be for a given wall type, what mortar and brick strength to use, how wide a cavity must be, how to handle openings and lateral support, and what to do near the coast where corrosion bites. It also covers free-standing boundary walls, retaining walls, lintels and where the damp-proof course goes.
Key requirements (plain English)
Keep the caveat in mind: these are orientation figures from public summaries, and the panel tables carry more detail in the full SABS text.
Mortar and unit strength. For a single-storey building on the empirical rules, hollow units of at least 3,0 MPa and solid units of at least 4,0 MPa, with Class II mortar. For the lower floor of a double-storey, hollow units of at least 7,0 MPa and solid units of at least 10,0 MPa, with Class II mortar.
Wall thickness. Single-leaf walls carrying sheeted or tiled roofs run at 90 mm, 110 mm or 140 mm nominal, depending on the panel size from the tables. Walls carrying concrete floors or roofs are either cavity construction with each leaf at least 90 mm, or single-leaf of at least 140 mm. A cavity is 50 mm wide at minimum and 110 mm at maximum. A foundation wall is not thinner than the wall it supports.
Maximum panel sizes. As an orientation, for an external wall in solid units, supported on both sides, with no openings, the brief gives length by height combinations such as: 90 mm single-leaf solid at roughly 3,2 m by 2,4 m; 110 mm single-leaf solid at roughly 4,5 m by 2,7 m; a 110-110 solid cavity at roughly 7,0 m by 3,3 m; 140 mm single-leaf solid at roughly 7,0 m by 3,3 m; and 190 mm collar-jointed solid at roughly 8,0 m by 4,6 m. Each table gives two alternative length-by-height combinations and allows linear interpolation between them, so read the full table for your exact case.
Openings (single-leaf solid, sheeted or tiled roof). At least 400 mm of masonry above the top of an opening. A minimum distance from the opening to a free edge of about 150 mm for solid units or 200 mm for hollow units. In walls supporting concrete floors, a maximum opening width of about 2 500 mm, with edge distances scaling with the floor span.
Lateral support. An intersecting wall giving vertical support should meet the supported wall at between 60 and 120 degrees, be at least 90 mm thick, and project beyond the unsupported face by at least one-eighth of the wall height and one-tenth of the wall length for internal walls (a calculated minimum for external walls).
Free-standing and boundary walls. A boundary wall is only minor building work if it is 1,8 m or lower and does not retain soil. It must use units of at least 3,0 MPa hollow or 5,0 MPa solid, with Class II mortar, and its height and pier spacing come from the Part K tables based on wind exposure. A masonry retaining wall typically needs rational design once it retains more than about 1,0 m of soil.
Coastal corrosion and wall ties. Within 30 km of the coast (or to the first inland mountain watershed), galvanizing of at least 750 g per square metre. Within 1 km of the coast or a large salt-water expanse, or within 3 km of corrosive industrial emissions, brickforce from pre-galvanized wire. In tidal or splash zones, stainless steel wall ties and brickforce.
DPC and lintels. A damp-proof course (the DPC, a moisture barrier) goes in at every point where a wall meets the ground or is in contact with moisture. Lintels are required above every window and door opening.
When you need a competent person
The bricklayer or masonry contractor is directly responsible for wall dimensions, mortar class, cavity width and tie spacing, and the supervising competent person should inspect at the key hold points (foundation wall, lintel installation and roof-plate level).
You need a competent person (structures) once you fall outside the Category 1 building limits (a basement, floor area over 80 square metres, or lateral-support spacing over 6,0 m), for double-storey buildings where the lower storey loads exceed 3,0 kN per square metre, for retaining walls holding back more than about 1 m of soil, and for framed buildings over four storeys.
Common mistakes
- Panel exceeds the maximum length by height for the wall type, especially 110 mm single-leaf hollow panels with large window openings and no reinforcement.
- No return wall or control joint at the end of a long external wall, leaving it without lateral support.
- A free-standing boundary wall over 1,8 m without pier sizing to the Part K tables.
- Wall ties not upgraded for the coast, with standard ties used within 30 km of the sea.
- Less than 400 mm of masonry above an opening.
Know someone who needs this?
Keep reading
Was this guide useful?
Didn't find what you were looking for?
Spotted something wrong or out of date? Email us at hello@kilnguides.co.uk.
In crisis? SADAG 0800 567 567 ·