Gambrel Barn Roof Angles
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.
Gambrel barn roof angles. You will need to make 22 5 degree angle cuts on the rafter joist ends that mate up to the top plate or header. 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. If you plan on building and installing your own gambrel roof you ll have to draw out plans first to determine the proper dimensions.
Gambrel roof framing geometry calculator inch this gambrel roof fits in a semicircle and starts as the top half of an equal sided octagon. Check overhang to calculate rafter overhang equal to the lower level cut at the full rafter depth. 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. Four angles needed with the gambrel roof design there are four angles that are used to make up a total of 180 degrees.
A gambrel roof is a popular roof style on many contemporary barns and sheds. If at all possible it looks the best at exactly half. Gambrel 2x4 truss measurements defined now we know all the necessary measurements to cut and make our first truss. Each truss piece will be 3 10 long on the top measurement and the angles cut will be 22 5 degrees off each end.
Gambrel roof framing geometry calculator metric this gambrel roof confines to a semicircle and starts as the top half of an equal sided octagon. 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. A gambrel has four angles at the peak at the wall and where the two rafters or truss chords connect.
A gable roof has only two rafter or truss chord angles a top cut at the peak and a bottom cut at the walls. Since the sum of the three angles in a gambrel roof is 180 degrees the angles you will need are as follows. To calculate a gambrel roof select gambrel roof from the roof type dropdown list or click on the appropriate toolbar button to calculate a. Gambrel roofs are symmetrical with two slopes on each side of the roof.
In other words if you start with a say 14 12 bottom pitch your top pitch should be 7 12 or greater. A gambrel style is often called a barn roof. Check overhang to calculate rafter overhang equal to the lower level cut at the full rafter depth. Its double or sometimes triple slopes on each side of a peak provide more space inside the roof which is attractive to homeowners too.