Flat Timber Roof Construction Details

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

Flat timber roof construction details. Ventilated batten void warm roof gable 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. 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. It is for that reason that the flat roof construction manual focuses on the subject of designing energy saving flat roofs free from damage. Normally a slope of inch per foot is used.

It dealt in detail with flat roof constructions and. Others would treat even steeper pitches as flat roofs. Flat roofs aren t actually flat but must slope to drain water. The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls.

If your flat roof is beginning to resemble a patchwork quilt then it s time to consider a more extensive treatment with your timber flat roof construction details. A popular method involves a cold application bitumen emulsion which is applied onto the surface. Usually a flat roof is built with a slight slope to provide some drainage. Timber framed and historic buildings may be framed with principal rafters or timber roof trusses.

Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls. 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. Modern timber roofs are mostly framed with pairs of common rafters or prefabricated wooden trusses fastened together with truss connector plates.

The construction of the flat roof is similar to that of the timber upper floor. Flat roofs became popular amongst early 1900s modernist architects because they removed the often complicated pitched roofs of traditional construction and replaced them with perfect straight lines. Applying a liquid waterproofing agent will often add a few more years to the roof. 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 definition of a flat roof according to bs 6229 is having a pitch less than 10 o to the horizontal however some in the industry would consider up to 15 o as their definition of a flat roof. When building a flat roof it is vital that a degree of falls is built into the construction to ensure rainwater run off. These lines gleamed against the sky in the same way as other products of industrialisation such as trains.