Flat Roof Framing Detail

When framing a flat roof you will need to create a slight incline.

Flat roof framing detail.

A roof is considered to be flat when it is of a slope of 1 5 o to the horizontal. And the line length measurement from the roof peak to the building wall is the hypotenuse. Of course you don t need to live in a modern house to deal with a flat roof. Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped roof.

Sizes of joists needed for flat roof construction. Some roofs actually slope in several directions ensuring optimal water runoff. This will help you create a flat roof framing plan. Flat roof construction for residential.

A flat roof has a slope of 1 8 per foot to 2 12. Old asbestos roofs are often replaced with flat roofs. Flat roofs are hard to replace. 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.

The framing of a basic gable roof is based on a right angle triangle and the various roof framing components fit the triangle. 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. You can do this with a foam layer that exactly fits your roof. Think of a flattened hip roof.

It is not ideal for snow or heavy rain but modern materials and proper drainage have helped. As you may imagine there is a fair amount of weight involved here in terms of boards felt etc. The rise or height of the roof at its peak is the altitude of the triangle. The run or half the building span is the base of the triangle.

If you build a flat roof try to have it slope in multiple directions to drains or gutters. Flat roofs are always built at a slight incline at least 1 8 inch per foot. Details for conventional wood frame construction the first approach to achieving a strong durable struc ture involving economical use of materials is to follow a. Although flat roofs are cheaper to build than pitched roofs they have a shorter life span.

But now flat roofs often are constructed with fewer layers because of improved waterproofing technology.