Flat Roof Framing Detail

The run or half the building span is the base of the triangle.

Flat roof framing detail.

Think of a flattened hip roof. Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped roof. This will help you create a flat roof framing plan. Old asbestos roofs are often replaced with flat roofs.

This could mean flat roofs may not raise the same red flags they used to. And the line length measurement from the roof peak to the building wall is the hypotenuse. Some roofs actually slope in several directions ensuring optimal water runoff. The rise or height of the roof at its peak is the altitude of the triangle.

As you may imagine there is a fair amount of weight involved here in terms of boards felt etc. 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. If you build a flat roof try to have it slope in multiple directions to drains or gutters. You can do this with a foam layer that exactly fits your roof.

Although flat roofs are cheaper to build than pitched roofs they have a shorter life span. It is not ideal for snow or heavy rain but modern materials and proper drainage have helped. 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. Flat roof construction for residential.

So any timber joists that are used need to be strong enough to support this weight. The framing of a basic gable roof is based on a right angle triangle and the various roof framing components fit the triangle. Cad details document name pdf dwg download all cad construction details 37 1 mb 3 4 mb mc01 identification of roof areas 694 kb 167 kb mc01a single layer underlayment 678 kb 302 kb mc01b double layer underlayment 711 kb 322 kb mc02 vent pipe flashing 626 kb 349 kb mc03 valley. A flat roof has a slope of 1 8 per foot to 2 12.

A roof is considered to be flat when it is of a slope of 1 5 o to the horizontal. When framing a flat roof you will need to create a slight incline. Flat roofs are hard to replace. But now flat roofs often are constructed with fewer layers because of improved waterproofing technology.

Flat roofs are always built at a slight incline at least 1 8 inch per foot.