Top and bottom plates were nominally 4 x 2” (100 x 50 mm), with the bottom plate laid directly over the floor joists – some early houses may have the wall plate directly supported on the piles (Figure 1).
Up until the 1890s, studs were occasionally mortised into top and bottom plates (Figure 2). This allowed the studs to be installed without nails, as nails were relatively expensive.
Studs of later villas may also be housed into the top and bottom plates. This allowed them to be cut to a common length with the housing, accommodating the variation in the sawn timber dimensions of the plates, and was said to reduce the risk of the framing twisting.
For two-storeyed villas, the first floor framing was usually supported by the lower floor wall framing, but there are examples where balloon framing was used – the studs ran the full height of the framing and the upper floor framing was supported on a stringer housed into the studs (see Figure 3).
Framed corners to external walls may have been formed with a single 4 x 4” (100 x 100 mm) corner stud with a batten fixed to it to allow the installation of the match lining to the inside (Figure 4). Battens were then fixed to the framing to allow the match lining to be fixed in place.
Corner and running joints in top and bottom plates were halved (Figures 5 and 6).
Loadbearing walls were generally the external walls and the internal walls running along each side of the corridor. Lintels over door openings would generally be a 4 x 2” (100 x 50 mm) on flat – undersized in terms of modern framing standards.
Internal walls other than those parallel to the corridor were non-loadbearing. Internal walls that joined into the external walls were generally constructed after the match lining had been fixed to the external framing (Figure 7).
The internal wall framing may not have been attached to a stud within the external wall – it was simply nailed at the top and bottom plate. Internal doors were not likely to be constructed with more than a 4 x 2” (100 x 50 mm) on flat as the lintel.
Lateral stability or bracing was provided by 6 x 1” (150 x 25 mm) at 45° let into housings in the stud at each crossing point and into the top and bottom plates (Figures 8 and 9).
Where walls were parallel to the bearers, the brace was housed into the bearer at the lower end (Figure 10).
The bracing strength of existing construction is often not known. What should be used in the bracing calculations required by building consent authorities when repairs or renovations are planned?
BRANZ tested a range of older bracing systems to provide wall bracing ratings. The results can be found in BRANZ Study Report SR305 Bracing ratings for non-proprietary bracing walls.
A small number of villas were constructed of double brick 9” (230 mm) thick internal walls and 9” (230 mm) or 13½” (345 mm) thick external walls, but these were considerably more expensive to build and the risk of earthquake damage was recognised. They tend to be more common in areas with lower earthquake risk such as Dunedin and Auckland.
Villa framing construction was the first to use nailing of framing members as well as for fixing claddings, match lining and internal finishing timbers as a matter of course. Initially, nails would have been imported – manufacture of framing nails from cut wire didn’t commence in New Zealand until the late 1880s/early 1890s.
Fixings for galvanised iron were lead head nails with bright steel shanks. Early lead head nails were made by the plumbers’ apprentices in their spare time, with local commercial manufacture commencing in the late 1880s.