For stability up the height of a wall lateral support is provided by floors and roofs as set out in Table 3.
Walls that provide support for timber floors are given lateral support by 30 x 5 mm galvanised iron or stainless steel ‘L’ straps fixed to the side of floor joists at not more than 2 m centres for houses up to three storeys and 1.25 m centres for all storeys in all other buildings. The straps are turned down 100 mm on the cavity face of the inner leaf of cavity walls and into solid wallings, as illustrated in Fig. 67.
Table 3 Lateral support for walls.
Lateral support from timber floors, where the joists run parallel to the wall, is provided by 30 x 5 mm galvanised iron on stainless steel strap anchors secured across at least two joists at not more than 2 m centres for houses up to three storeys and 1.25 m for all storeys in all other buildings.
The ‘L’ straps are turned down a minimum of 100 mm on the cavity side of inner leaf of cavity walls and into solid walling. Solid timber strutting is fixed between joists under the straps as illustrated in Fig. 67.
Solid floors of concrete provide lateral support for walls where the floor bears for a minimum of 90 mm in both solid and cavity walls, as illustrated in Fig. 67.
To provide lateral support to gable end walls to roofs pitched at more than 15° a system of galvanised steel straps is used. Straps 30 x 5 mm are screwed to the underside of timber noggings fixed between three rafters, as illustrated in Fig. 68, with timber packing pieces between the rafter next to the gable and the wall.
The straps should be used at a maximum of 2 m centres and turned down against the cavity face of the inner leaf of a whole building block or down into a solid wall.
Fig. 67 Floors providing lateral restraint to walls.
Fig. 68 Lateral support to gable ends.
Fig. 69 Length of walls.
To provide stability along the length and at the ends of loadbearing walls there should be walls, piers or chimneys bonded to the wall at intervals of not more than 12 m, to buttress and stabilise the wall.
The maximum spacing of buttressing walls, piers and chimneys is measured from the centre line of the supports as illustrated in Fig. 69. The minimum length of a return buttressing wall should be equal to one-sixth of the height of the supported wall.
To be effective as buttresses to walls the return walls, piers and chimneys must be solidly bonded to the supported wall.