Gambrel Roof Slope

A gambrel or barn style roof is simply a gable roof with a change in slope partway up the roof.

Gambrel roof slope.

A roof similar to a mansard but sloped in one direction rather than both. The shallower the top pitch the more squatty it will look. Well let s face it it s a very attractive roof design but there are practical considerations as well. Besides its unique appearance a gambrel roof also serves to maximize the usable floor space in the attic area.

Check overhang to calculate rafter overhang equal to the lower level cut at the full rafter depth. Compare with bell roof. Similar to mansard the lower side of the gambrel roof has an almost vertical steep slope while the upper slope is much lower. The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7.

Maximum height in the center height at the pitch break how far in from the side wall a six foot height occurs etc. A gambrel style is often called a barn roof. A gambrel or gambrel roof is a usually symmetrical two sided roof with two slopes on each side. Anything less than this will ultimately result in a roof that leaks if you plan on putting shingles on it.

It also shows you various heights along the interior of the sloped gambrel ceiling ie. A gambrel or a barn roof is much like mansard in a sense that it has two different slopes. In other words if you start with a say 14 12 bottom pitch your top pitch should be 7 12 or greater. When you are designing your shed roof whether it be a gambrel gable or saltbox you should never have any roof pitch less than a 3 12.

This means that for every 12 horizontal run you must have at least 3 of rise. A roof with the shallow slope below the steeper slope at the eaves. Gambrel roof framing geometry calculator inch this gambrel roof fits in a semicircle and starts as the top half of an equal sided octagon. Its double or sometimes triple slopes on each side of a peak provide more space inside the roof which is attractive to homeowners too.

This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. Move slider or directly enter angle to alter sweep angle of lower rafters and change the shape. If at all possible it looks the best at exactly half. The rule of thumb that i use when designing a gambrel is that the top pitch should be no less than half the pitch of the bottom.