Timber Flat Roof Construction Details

A flat roof must be strong durable and stable throughout its lifetime.

Timber flat roof construction details.

For additional stability you can also use steel joists that are built into one or both of the walls. Timber trusses also are built in a variety of styles using wood or metal joints. The construction of the flat roof is similar to that of the timber upper floor. They are designed by the manufacturer for each specific building.

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. Boardsmust have a nominal thickness of min. The steels or rsj s rolled steel joists are often built into one or both walls to give added stability to the roof structure. Others would treat even steeper pitches as flat roofs.

3 05 timber frame pitched roof. 24 mm 20 and should have. When building a flat roof it is vital that a degree of falls is built into the construction to ensure rainwater run off. A roof is defined in bs 6229 as a flat roof if it has a pitch of 10 degrees or less.

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. 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. Having a manual for warm flat roof construction with details and a summary of rules to follow helps.

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. Heavy timber rafters typically spaced 240 cm 8 ft to 370 cm 12 ft apart are called principal rafters. 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. Pre manufactured roof trusses come in a wide variety of styles.

The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls. A popular method involves a cold application bitumen emulsion which is applied onto the surface. It must provide adequate protection against the elements keeping the buildings structure and interior dry.