Structural Timber Flat Roof Construction Details

Flat roofs of this type are usually finished in steel roof sheet and fall towards a special type of gutter called a box gutter.

Structural timber flat roof construction details.

The steels or rsj s rolled steel joists are often built into one or both walls to give added stability to the roof structure. This will give additional stability to the roof structure. Flat roofs are hard to replace. This could mean flat roofs may not raise the same red flags they used to.

2306 4 3 particleboard shear walls. Heavy timber rafters typically spaced 240 cm 8 ft to 370 cm 12 ft apart are called principal rafters. The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls. Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped roof.

Besides the various loads acting on the flat roof the chapters of this section discuss potential primary structures and. 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. The design shear ca pacity of particleboard shear walls shall be in accordance 2003 international building code 467 wood table 2306 3 1 continued recommended shear pounds per foot for wood structural. Collar ties rafter ties tension beams structural ridge beams.

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. Pre manufactured roof trusses come in a wide variety of styles. 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. Part b structure investigates the structural aspects of flat roofs.

Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing 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. But now flat roofs often are constructed with fewer layers because of improved waterproofing technology.

Some of these can support the roof and prevent ridge sagging and wall spreading. They are designed by the manufacturer for each specific building. Trada and approved document part a give guidance on sizes of joists for flat roofs relating to spans and loading. The construction and allowable load provisions of sections 2306 3 4 and 2306 3 5.