A floor framework, at its simplest, is made up of bearers which rest on piers, and floor joists which are nail-fixed to the bearers.

The cross section size of the bearers is governed by their span (i.e. the distance between piers) and the spacing and length of the floor joists.

The cross section size of the joists is governed by their span (i.e. the distance between bearers) and the spacing which in turn can be affected by the type and quality of flooring materials which will be fixed to them.

The flooring materials may be tongued and grooved strip timber flooring usually of a finished thickness of 19mm (21mm for cypress pine), of various species and usually nail fixed to floor joists spaced at 450mm centre-centre. Some selected hardwood products (selected species) are capable of supporting domestic floor loadings over a 600mm span, hence joists could be spaced to suit if the owner/builder/designer so chooses.

Sheet flooring such as structural or flooring grade plywood and flooring grade particleboard similarly are available in grades and thickness which satisfy 450 or 600mm joist spacing.

Some house designs require floor bearers or floor joists to be cantilevered and the length or extent of cantilever could govern the cross section size of timber to be specified (rather than the simple joist or bearer span).

Wall Framing


A timber wall frame consists of a bottom plate, vertical wall studs and a top plate. An additional essential component is some form of wall bracing which can be of timber or metal angle "let-in" or notched into the wall studs and plates.

Such bracing is desirably inclined to the horizontal plates (and vertical studs) at approximately 45 degrees (for maximum effectiveness). Wall frame bracing can also be obtained from two metal tension straps or approved sheet bracing (grades of plywood, particleboard. hardboard).

Within the wall frame, fixed between the vertical studs, is usually a series of "noggings" acting as spacers or blocking, and some provision for window or door openings. Such framed openings usually comprise two wall studs with an upper component termed a lintel or header, which is sized to support the roof loading, and perhaps a lower sill plate or sill trimmer.

Additional studs may be fixed to provide support for lintels, to provide fixing points for attachment of other wallframes and so on. Common stud spacings are 450mm or 600mm centre-centre.