Roof form and framing: original details

Villas used hip roofs for the main building, with gables and valleys.

Roof form

The use of small pitched roofs with hips, gables and valleys meant that villas could accommodate the limited span available with the 4 x 2” (100 x 50 mm) framing commonly used. 

Typically, roofs incorporated an internal gutter (Figures 1 and 2).

However, due to leaking problems, the internal gutter was often omitted in villas built late in the period, by strutting the rafters and increasing the roof height (Figures 3 and 4).


The pitch or slope of the main roof for villas varied from 30–45°, and pitch was not always consistent. For example, for a small gabled roof over the wrap-around portion of a veranda or where a turret was constructed, the pitch may be steeper, or roofs sloping into an internal gutter may have a slacker pitch to accommodate the design of the internal gutter (see Figure 1). 


Lean-to additions over service areas were commonly constructed at much lower pitches – typically 5–10° – and may be concealed behind a parapet wall (figure 5).

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Roof framing

The quality of timber varied. Most rafters were 4 x 2” (100 x 50 mm) rough sawn at 18” (450 mm) centres, supported by props or underpurlins at mid span with a 6 x 1” (150 x 25 mm) ridge board at the apex (Figure 6).

Figure 7 shows a typical valley detail for corrugated iron roofing.

While spans of rafters were generally not more than 7–8’ (2.1–2.4 m), typically they were undersized for the span when compared to what is required now, particularly when a heavy roof was used. Ceiling joists like rafters were typically 4 x 2” (100 x 50 mm) at 18” (450 mm) centres.

Roof framing was constructed on site. Quality varied between installations and may have been altered over time with removal of flues and fireplaces, installation of header tanks for hot water systems, and so on.

Construction of rafters varied from that of later buildings in that ceiling joists cantilevered past the line of the outside walls to form the eaves, and rafters landed onto the ceiling joists (Figures 8 and 9) with a 4 x 2” (100 x 50 mm) or 4 x 1” (100 x 25 mm) ribbon board to anchor the ends of the rafters.

For metal roofing, 3 x 2” (75 x 50 mm) or 4 x 2” (100 x 50 mm) purlins on flat were used and located to suit the length of roofing sheets being used. Closely spaced battens were used for tiled roofs, and close-butted 1” (25 mm) thick boarding was used for shingles.

For shingles or slate, the roof was generally fully sarked with close-butted 1” (25 mm) boarding laid across the rafters. Tiles were laid over 2 x 1” (50 x 25 mm) tile battens. 

Roof underlays were not used in the first roofing installations and may not be present in subsequent roof replacements.