A roof is considered to be flat when it is of a slope of 1 5 o to the horizontal.
Flat roof framing plan details.
Think of a flattened hip roof.
So any timber joists that are used need to be strong enough to support this weight.
Flat roofs are always built at a slight incline at least 1 8 inch per foot.
The run or half the building span is the base of the triangle.
A flat roof has a slope of 1 8 per foot to 2 12.
Sizes of joists needed for flat roof construction.
Roof plans a roof plan is used to show the shape of the roof.
Old asbestos roofs are often replaced with flat roofs.
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 roofs are hard to replace.
Although flat roofs are cheaper to build than pitched roofs they have a shorter life span.
Some roofs actually slope in several directions ensuring optimal water runoff.
Flat roof construction for residential.
But now flat roofs often are constructed with fewer layers because of improved waterproofing technology.
And the line length measurement from the roof peak to the building wall is the hypotenuse.
When framing a flat roof you will need to create a slight incline.
The rise or height of the roof at its peak is the altitude of the triangle.
If you build a flat roof try to have it slope in multiple directions to drains or gutters.
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.
Materials such as the roofing material vents and their location.
This will help you create a flat roof framing plan.
You can do this with a foam layer that exactly fits your roof.
Roof framing and drainage plans will be discussed in chapter 30.