Timber is one of the most traditional and commonly used building materials in the world due to its ease of use, affordability and flexibility. The basics of building a timber floor are outlined below.
A timber floor is constructed on top of piers ( usually brick ). The piers must have the ant capping laid before the first layer of large timber members called bearers are put down. The bearers in turn support joists of a slightly smaller cross sectional dimension. The joists are commonly fixed to the bearers using nails or gang nails.
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 14 to 19mm (21mm for cypress pine), of various species and usually nail fixed or glued to floor joists. 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).
Flooring Systems 
