About this calculator
A free-standing brick boundary or garden wall: the pier size and spacing SANS 10400-K allows for the height, plus bricks, foundation concrete and mortar.
How it’s calculated
SANS 10400-K table 17 sets how high a free-standing wall of solid units may be. Without piers, a single-brick (110 mm) wall may be 1.0 m high and a double-brick (220 mm) wall 1.8 m. With piers on one side, a 110 mm wall reaches 1.5 m with 330 × 330 mm piers at 1.8 m centres, or 1.9 m with 550 × 330 mm piers at 2.0 m centres; a 220 mm wall reaches 2.3 m with 660 × 440 mm piers at 3.2 m centres. With piers on both sides, 110 mm walls reach 1.6 m (550 × 330 mm piers at 1.8 m) and 220 mm walls 2.1 m (660 × 440 mm at 3.2 m).
Piers = wall length ÷ pier spacing, rounded up, plus one, because the wall must end in a pier. Bricks are 52 per m² for single and 104 per m² for double brick, plus the extra bricks in each pier course (83 mm per course), plus 5%. The foundation is a 600 × 200 mm strip, and mortar is Class II from the Concrete Society’s figures.
Worked example
With these inputs:
- Wall length
- 20 m
- Height above ground
- 1.8 m
- Wall
- Double brick (220 mm nominal)
- Piers
- Piers on one side
- Supply as
- Mix on site (cement, sand and stone)
- Concrete mix
- Low strength (house foundations)
- Waste allowance
- 10%
the result is:
- Bricks
- 5,261 bricks
- SANS 10400-K table 17
- up to 2.3 m, piers 660 × 440 mm at up to 3.2 m centres
- Piers
- 8
- Foundation (600 × 200 mm strip and pier bases)
- 3.32 m³
- Cement (50 kg bags)
- 20 bags
Tips from the trade
- Walls taller than the table allows, retaining walls and walls on a boundary with a big level difference need an engineer’s design.
- Check your title deed and estate rules for height limits before building.
- Leave vertical control joints in long walls at the spacing in SANS 10400-K table 19, down to the top of the foundation.
Common questions
How high can a boundary wall be without piers?
Under SANS 10400-K table 17, 1.0 m for a single-brick (110 mm) wall and 1.8 m for a double-brick (220 mm) wall built of solid units. Higher walls need piers or a design.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and SANS 10400 (the National Building Regulations) and your local municipality before ordering.