Most houses of this era had timber floors supported by perimeter walls or piles.
Typical foundations for suspended timber floors included:
- precast concrete piles and a continuous, in-situ, reinforced concrete perimeter foundation wall (Figure 1)
- precast concrete piles with no foundation walls (typically from 1946 onwards)
- cast in situ concrete corners with the remaining support provided by precast concrete piles with base boards
- on sloping sites, jackframing on precast concrete piles and a continuous, in-situ, reinforced concrete foundation wall (on sloping sites)
Where there were no continuous foundation walls, the concrete piles and subfloor framing were concealed by horizontal timber battens fixed to the perimeter walls. Spaces between the battens provided subfloor ventilation.
A continuous, in-situ, reinforced concrete perimeter foundation wall was a common foundation construction. It was always used to provide support where the cladding was brick veneer (Figure 2).
The foundation wall thickness was typically 5” (125 mm) for single storey construction and 6” (150 mm) for two storey construction. Half-piles were cast integrally with the foundation wall to support bearer ends (Figure 3).
Reinforcing generally consisted of two ½”(12 mm) diameter reinforcing rods at the bottom of the wall, which were typically spaced at 15” (375 mm), and one or two ½”(12 mm) diameter reinforcing rods, depending on whether single- or two-storey construction, at the top of the wall (Figures 4 and 5). Two-storey construction had additional horizontal and vertical reinforcing rods, either 3/8” or ½” (9.5 or 12 mm) centres both ways (Figure 6).
Where a single storey foundation wall exceeded 6’ (1.8 m) in height above ground, it was constructed as for a two storey construction.
The depth of the foundation wall was a minimum of 12” (300 mm) or onto solid bearing ground. Above ground the height was a minimum of 12” (300 mm), but foundation walls of state houses were often higher than this.
Houses built on hillside sites could have foundation walls of 2 m or more in height. The foundation wall could be stepped and extended in height by jack stud timber framing or the foundation wall could be continuous to create a basement space that provided useful storage space (Figure 7).
Subfloor ventilation was provided by grilles spaced regularly around the concrete foundation wall.
In situ concrete foundation walls were typically finished on the exterior with a spatter-dash sand/cement plaster or, in some cases, a solid plaster.
Piles were precast concrete typically 8” x 8” (200 x 200 mm) square, arranged in rows and spaced to support bearers spanning 54–72” (1400–1800 mm). The rows of piles were generally 54–78” (1400 mm–2000 mm) apart.