Timbers. The sizes of timbers are governed by the needs of the building. The sills of a moderate-sized dwelling should be 4" X 6", 6" X 6", or 6" X 8". The plates should be 4" X 4" or 4" X 6", or the same size one way as the width of the studs.

The studs should be 2" X 4" for the main partitions and the outside walls, while for cross and minor partitions 2" X 3" studding is sufficient.

Stair strings or carriages should be 2" X 10". For lower floor joists from 12' to 14' long, with one row of bridging, material 2" X 10" should be used, though for a light framed house, 2" X 8", if well bridged, is generally sufficient. For spans of over 14', 2" x 12" should be used.

Second floor joists should be 2" X 8" or 2" X 10", though the former, with bridging, is generally used in light buildings and for short spans.

Rafters, not over 14' long, if well supported by purlins and collar beams, will be satisfactory if made of 2" X 4" material. Rafters longer than 14' should be made of 2" X 5" or 2" X 6", unless very well supported.

It is not a good plan to make a roof heavier than it need be, as unnecessary weight adds to the difficulty of keeping the building in shape. Unless the plates are well tied, the house is apt to spread at the eaves, causing great difficulty if there is a room in the attic.

Collar beams over 8' long should be made of 2" X 6", though for a light framed house 1" X 6" is often used.