Gambrel Barn Roof Angles

Gambrel roof framing geometry calculator metric this gambrel roof confines to a semicircle and starts as the top half of an equal sided octagon.

Gambrel barn roof angles.

Gambrel 2x4 truss measurements defined now we know all the necessary measurements to cut and make our first truss. The easiest way to get these angle measurements on the ends will be with the use of a speed square. 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.

A gambrel has four angles at the peak at the wall and where the two rafters or truss chords connect. To calculate a gambrel roof select gambrel roof from the roof type dropdown list or click on the appropriate toolbar button to calculate a. In other words if you start with a say 14 12 bottom pitch your top pitch should be 7 12 or greater. Since the sum of the three angles in a gambrel roof is 180 degrees the angles you will need are as follows.

You will need to make 22 5 degree angle cuts on the rafter joist ends that mate up to the top plate or header. Gambrel roofs are symmetrical with two slopes on each side of the roof. A gambrel roof is a popular roof style on many contemporary barns and sheds. If you plan on building and installing your own gambrel roof you ll have to draw out plans first to determine the proper dimensions.

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. A gable roof has only two rafter or truss chord angles a top cut at the peak and a bottom cut at the walls. A gambrel or barn style roof is simply a gable roof with a change in slope partway up the roof.

Gambrel roof framing geometry calculator inch this gambrel roof fits in a semicircle and starts as the top half of an equal sided octagon. 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. 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. Each truss piece will be 3 10 long on the top measurement and the angles cut will be 22 5 degrees off each end.

Check overhang to calculate rafter overhang equal to the lower level cut at the full rafter depth. If at all possible it looks the best at exactly half. A gambrel style is often called a barn roof. Move slider or directly enter angle to alter sweep angle of lower rafters and change the shape.