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.
Timber flat roof construction details.
Trada and approved document part a give guidance on sizes of joists for flat roofs relating to spans and loading.
The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls.
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.
Applying a liquid waterproofing agent will often add a few more years to the roof.
For additional stability you can also use steel joists that are built into one or both of the walls.
Timber in the form of rough sawn or planedboards or planks can be used as the loadbearing deck to a flat roof fig.
The steels or rsj s rolled steel joists are often built into one or both walls to give added stability to the roof structure.
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.
A popular method involves a cold application bitumen emulsion which is applied onto the surface.
Boardsmust have a nominal thickness of min.
24 mm 20 and should have.
Having a manual for warm flat roof construction with details and a summary of rules to follow helps.
Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls.
Timber flat roof carports timber flat roof construction timber flat roof construction details timber flat roof deck timber flat roof detail timber flat.
They are designed by the manufacturer for each specific building.
3 05 timber frame pitched roof.
When building a flat roof it is vital that a degree of falls is built into the construction to ensure rainwater run off.
Pre manufactured roof trusses come in a wide variety of styles.
It must provide adequate protection against the elements keeping the buildings structure and interior dry.
A roof is defined in bs 6229 as a flat roof if it has a pitch of 10 degrees or less.
Others would treat even steeper pitches as flat roofs.
Heavy timber rafters typically spaced 240 cm 8 ft to 370 cm 12 ft apart are called principal rafters.
The construction of the flat roof is similar to that of the timber upper floor.
