Gambrel Roof Angles Formula

Besides its unique appearance a gambrel roof also serves to maximize the usable floor space in the attic area.

Gambrel roof angles formula.

The purlin method calculates cuts that bisect the angles at the roof joints. Reverse that for the bottom angle. With overhang selected drag slider to increment decrement birdsmouth seat width to suit. If you are thinking of a building project that involves a gambrel roof design here are a few tips to help you calculate the angles.

Check overhang to calculate rafter overhang equal to the lower level cut at the full rafter depth. With the gambrel roof design there are four angles that are used to make up a total of 180 degrees. The lower slope length is measured from outside wall to the start of the upper sloped roof section. 45 degrees where the joists meet up with the top plate or header and 90 where the joists meet in the middle at the ridge board.

Gambrel roof framing geometry calculator metric this gambrel roof confines to a semicircle and starts as the top half of an equal sided octagon. You will need to make 22 5 degree angle cuts on the rafter joist ends that mate up to the top plate or header. With overhang selected drag slider to increment decrement birdsmouth seat width to suit. 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. Determine a pitch for the top slope of the gambrel roof the rise in inches per foot from the midpoint connection to the peak. 7 12 or a rise of 7 inches per foot is a common top gambrel pitch. Gambrel roof framing geometry calculator inch this gambrel roof fits in a semicircle and starts as the top half of an equal sided octagon.

Gambrel roof a gambrel or barn style roof is simply a gable roof with a change in slope partway up the roof. Move slider or directly enter angle to alter sweep angle of lower rafters and change the shape. Make that pitch 12 7 a drop of 7 inches per foot from the connection to the wall. Move slider or directly enter angle to alter sweep angle of lower rafters and change the shape.