Flat Timber Roof Structure

This house s roof construction used prefabricated trusses from turner timber with dormer windows factored into the design on the front elevation image credit.

Flat timber roof structure.

Flat roofs can be used to create box shapes cantilevered into daring overhangs or can be planted to create usable vegetated gardens. A cavity closer should be provided to the top of the walls to prevent fire spread and to stop damp air entering the roof space. Load bearing or primary structure usually constructed in timber in a residential construction. The steels or rsj s rolled steel joists are often built into one or both walls to give added stability to the roof structure.

The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls. Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls. Where a new flat roof abuts an existing external wall the joists can be hung on metal joist hangers which are fixed to a horizontal timber plate wall bolted to the wall. In most cases the roof can be erected in a day.

Works best in simple roof designs. For additional stability you can also use steel joists that are built into one or both of the walls. Uses relatively small timber sections. This will give additional stability to the roof structure.