Timber Frame Flat Roof Construction Details

The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls.

Timber frame flat roof construction details.

Depending on the design of the trusses you re making any number of bracing joints will be necessary. This will give additional stability to the roof structure. Trada and approved document part a give guidance on sizes of joists for flat roofs relating to spans and loading. Timber in the form of rough sawn or planedboards or planks can be used as the loadbearing deck to a flat roof fig.

Timber frame standard details september 09 building 1 grosvenor court hipley street old woking surrey tel. On a basic level flat roof construction comes in the form of roofing timbers or joists as they are more commonly known or steels that are laid across two uprights walls in most cases. The original roof was built using purlins beams extending between gable ends. Timber framing in our time power tools have made the components for the timber frame easier to refine but the methods for joining and principles of construction are largely unchanged from the 1600 s here a timberwright lays out a knee brace to be inserted in a mortise cut in the column and beam to give the bent additional lateral stability.

Very simple trusses work on a principle of thirds. Boardsmust have a nominal thickness of min. 44 0 1483 769518 fax. Thermal bridges can account for 35 50 of overall fabric.

For additional stability you can also use steel joists that are built into one or both of the walls. The construction of the flat roof is similar to that of the timber upper floor. The steels or rsj s rolled steel joists are often built into one or both walls to give added stability to the roof structure. Below is a sketch of the original roof wall structural details for this building.

A super basic a frame roof will require anywhere between 4 and 8 depending on the size of the rafters with plumb cuts necessary for each angle in the brace. 3 05 timber frame pitched roof. 44 0 1483 770863 e mail. Thermal bridges occur at all junctions in the building as well as when penetrations of the thermal insulation envelope occur.

Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls. 24 mm 20 and should have.