Timber Frame Flat Roof Detail

Intermediate floor joist parallel 4 3.

Timber frame flat roof detail.

Parapet detail joists parallel details in section 4. Similar to the abutment of a lean to roof lead flashing is chased into the external block allowing it to overlap the lead upstand coming from the tiles. Parapet detail joists perpendicular 3 13. Having a manual for warm flat roof construction with details and a summary of rules to follow helps.

The steels or rsj s rolled steel joists are often built into one or both walls to give added stability to the roof structure. Dormer in section 3 11. Flat roof joist and decking 3 10. This is used for refurbishment e g.

Trada and approved document part a give guidance on sizes of joists for flat roofs relating to spans and loading. Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls. The construction of the flat roof is similar to that of the timber upper floor. Refurbishing an existing timber joisted flat roof which has no insulation.

24 mm 20 and should have. Boardsmust have a nominal thickness of min. The abutment detail of a flat roof is vital in order to prevent moisture penetration. Roof panels 3 8 1 roof panel connections 3 9.

Dormer in perspective view 3 12. Collar ties rafter ties tension beams structural ridge beams. Some of these can support the roof and prevent ridge sagging and wall spreading. A cold flat roof is one where the insulation is between or between and below the roof joists.

Very simple trusses work on a principle of thirds. 3 06 timber frame timber flat roof 3 07 timber frame timber flat roof with parapet 3 08 timber frame lintel at window head 3 09 timber frame windows and doors jambs and cills specification within an example should 3 10 timber frame ground bearing floor insulation above slab 3 11 timber frame ground bearing floor. Timber in the form of rough sawn or planedboards or planks can be used as the loadbearing deck to a flat roof fig. The insulation is below the deck but above the plasterboard.

For additional stability you can also use steel joists that are built into one or both of the walls. 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.