Gambrel Roof Pitch Angles

You want to try and use angles that are as close to 45 as you can get for both ease of construction and good strength.

Gambrel roof pitch angles.

This means that for every 12 horizontal run you must have at least 3 of rise. Reverse that for the bottom angle. Determine a pitch for the top slope of the gambrel roof the rise in inches per foot from the midpoint connection to the peak. The purlin method calculates cuts that bisect the angles at the roof joints.

7 12 or a rise of 7 inches per foot is a common top gambrel pitch. Besides its unique appearance a gambrel roof also serves to maximize the usable floor space in the attic area. Four angles needed with the gambrel roof design there are four angles that are used to make up a total of 180 degrees. Depending on the size of the roof and the pitch of the roof these angles will change.

Move slider or directly enter angle to alter sweep angle of lower rafters and change the shape. Gambrel roof framing geometry calculator metric this gambrel roof confines to a semicircle and starts as the top half of an equal sided octagon. Make that pitch 12 7 a drop of 7 inches per foot from the connection to the wall. Check overhang to calculate rafter overhang equal to the lower level cut at the full rafter depth.

Gambrel roof framing geometry calculator inch this gambrel roof fits in a semicircle and starts as the top half of an equal sided octagon. Move slider or directly enter angle to alter sweep angle of lower rafters and change the shape. Anything less than this will ultimately result in a roof that leaks if you plan on putting shingles on it.