Floors: original details

Most 1940s-60s houses had tongue-and-groove wooden flooring supported on timber joists.

Subfloor framing

Bearers were 4 x 3” (100 x 75 mm) or 5 x 3” (150 x 75 mm), laid on edge on piles over a damp proof course. Where bearers were required to be joined, either a running joint or a halved joint (at corners) were typically used. They were tied to piles with No. 8 SWG (standard wire gauge), galvanised mild steel wire ties and secured in place with galvanised staples (Figures 1 and 2).

Floor framing typically consisted of either 4 x 2” (100 x 50 mm) or 5 x 2” (125 x 50 mm) joists spaced at 16–19” (400–480 mm) centres over the bearers (Figures 3 and 4).

Perimeter joists running parallel to the direction of the joists were doubled. The perimeter joists that ran perpendicular to the direction of the joists were either trimmed with a boundary joist or had solid blocking (Figure 5) or herringbone strutting (Figure 6) between joists.

Where the bottom plate of an internal loadbearing wall was to be parallel to the joists, joists were also doubled (or tripled) with a packer to provide full support to the bottom plate and support for the end of the floorboards.

Jointing occurred over bearers and joists were either overlapped by at least 12” (300 mm) or joists were butted with a flitch plate.

At the edge of the building, joists were supported on a 4 x 2” (100 x 50 mm) or 4” x 3” (100 x 75 mm) plate laid on the flat on a bituminous damp proof course and fixed to the top of the concrete wall.

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Timber floorboards through this period were typically rimu or matai, tongue and groove (T&G) boards, 25/32” (19.8 mm) thick and could be in widths of 3½, 4½ and 5½” (90, 115 and 140 mm).

Typical fixing for each board was to be double-nailed to every joist with fixings approximately ½” (12 .7 mm) from the edge of the boards (Figure 7).

Secret nailing was sometimes used, but a different board profile with a stronger tongue to make it suitable for the secret nailing was then used (Figure 8).

The flooring was laid after the roof and wall cladding were completed and before any internal building work was carried out, to provide a working platform. Laying of floorboards could be started in the middle of the building (depending on the layout of the rooms) but was more commonly started at one edge of the building starting from the external wall plate.

It was not uncommon for flooring to be loose laid upside down over the joists then turned over and fixed after the building was weathertight and the ceiling fixed in place.

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Floor finishes

Timber floors were generally varnished except in the kitchen, laundry and bathroom, which had linoleum laid over the floorboards.

Particleboard was introduced during the later 1960s, and with this came the widespread use of fitted carpet, vinyl sheet flooring and peel and stick vinyl tiles. This period also saw the introduction of ceramic and cork tiles as a floor finish.