Gambrel Roof Pitch Angles

This means that for every 12 horizontal run you must have at least 3 of rise.

Gambrel roof pitch angles.

Reverse that for the bottom angle. Move slider or directly enter angle to alter sweep angle of lower rafters and change the shape. 7 12 or a rise of 7 inches per foot is a common top gambrel pitch. Check overhang to calculate rafter overhang equal to the lower level cut at the full rafter depth.

Four angles needed with the gambrel roof design there are four angles that are used to make up a total of 180 degrees. Gambrel roof framing geometry calculator metric this gambrel roof confines to 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. 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.

Check overhang to calculate rafter overhang equal to the lower level cut at the full rafter depth. Depending on the size of the roof and the pitch of the roof these angles will change. Besides its unique appearance a gambrel roof also serves to maximize the usable floor space in the attic area. Gambrel roof framing geometry calculator inch this gambrel roof fits in a semicircle and starts as the top half of an equal sided octagon.

The purlin method calculates cuts that bisect the angles at the roof joints. Determine a pitch for the top slope of the gambrel roof the rise in inches per foot from the midpoint connection to the peak. Anything less than this will ultimately result in a roof that leaks if you plan on putting shingles on it.