Floor loads
Whether the bearers are supporting load bearing walls or only floor loads, the area of the floor supported by an individual bearer must be determined. This is referred to as the floor load width (FLW).
Where the bearer supports load-bearing walls the type of roof covering also needs to be determined. Tile roofs impart a heavier dead load on the bearers than sheet roofs.

Refer to Figure 3.4.4.1, Table a of the Building Code of Australia.