Page 28 - Build 161

NZS 3604:2011 REQUIREMENTS FOR STEPPED FOUNDATION WALLS
BUILD
Stepped foundation walls
Foundation walls provide support to the external walls of buildings, and on at sites, their design and construction is quite straightforward. When the site has uneven or sloping ground, however, requirements are more complex.
RIGHT
BY ALIDE ELKINK,
FREELANCE TECHNICAL WRITER, WELLINGTON
ground level
wall/top plate
2.0 m maximum
2.6 m maximum for maximum length of 1.5 m
450 mm minimum
600 mm minimum step reinforcing in foundation footing
450 mm minimum
1.2 m minimum, 5.0 m maximum
additional D12 reinforcing with 75 mm minimum concrete cover to steel required for stepped foundation wall. (Note: Foundation wall reinforcing as per NZS 3604:2011 Figures 6.13, 6.14 and 6.15 omitted for clarity)
stepped foundation wall
450 mm minimum;
1.5 m maximum overlap
jack studs 450 mm minimum
225 mm minimum
reinforcing in foundation footing
200 mm or solid bearing ground
600 mm minimum step
foundation wall footing sizes as per NZS 3604:2011 clause 6.11.4.2 as follows:
• Figure 6.13 for cantilever foundation wall
• Figure 6.14 for single-storey building
Figure 1 Stepped foundation wall footing and step reinforcing only.
• Figure 6.15 for 2-storey building
UNDER NZS 3604:2011 Timber-framed buildings, foundation walls may be constructed from reinforced concrete, reinforced concrete masonry or a combination of the two.
See NZS 3604:2011 for foundation walls
The footing sizes, width of walls and reinforce- ment requirements should be as shown in
NZS 3604:2011:
● Figure 6.13 for cantilever foundation walls ● Figure 6.14 for single-storey buildings
● Figure 6.15 for 2-storey buildings.
26 — August/September 2017 — Build 161