Structural Timber Flat Roof Construction Details

Yet for historic modern style buildings like this old house s cambridge tv project flat roofs are at the core of the architecture meant to reflect the broad horizontal lines of the natural landscape.

Structural timber flat roof construction details. Flat roofs are hard to replace. The construction of the flat roof is similar to that of the timber upper floor. Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls. Flat roofs of this type are usually finished in steel roof sheet and fall towards a special type of gutter called a box gutter.

Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped 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 basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls. The construction and allowable load provisions of sections 2306 3 4 and 2306 3 5.

They are designed by the manufacturer for each specific building. Heavy timber rafters typically spaced 240 cm 8 ft to 370 cm 12 ft apart are called principal rafters. 2306 4 3 particleboard shear walls. Trada and approved document part a give guidance on sizes of joists for flat roofs relating to spans and loading.

Some of these can support the roof and prevent ridge sagging and wall spreading. But now flat roofs often are constructed with fewer layers because of improved waterproofing technology. Part b structure investigates the structural aspects of flat roofs. Of course you don t need to live in a modern house to deal with a flat roof.

Besides the various loads acting on the flat roof the chapters of this section discuss potential primary structures and. Some observers suggest it s harder to replace a flat roof than a traditional pitched shingle roof because of the labor required to remove its layers especially on older flat roofs. Pre manufactured roof trusses come in a wide variety of styles. This article describes and illustrates the different types of support that prevents roof sagging and wall bulging at buildings including definitions of collar ties rafter ties and structural ridge beams.

For additional stability you can also use steel joists that are built into one or both of the walls. 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. Collar ties rafter ties tension beams structural ridge beams. This could mean flat roofs may not raise the same red flags they used to.