How To Build A 45 Degree Angle Roof

This means if a roof rises 4 in the length of 12 your roof pitch would be 4 12 or 18 43 degrees.

How to build a 45 degree angle roof. To determine material quantities you need to do some calculations. On blue prints architects engineers usually display the pitch of a roof in the format shown on the image where number 4 represents a rise and number 12 represents a length. The square also comes with three leveling vials which make it easy to measure the pitch of existing structures. Install the corbels next.

Place the angled pieces inside your l s and screw into place to finish assembling the corbels. Set unit run place the other square gauge at the run unit measurement mark. Before miter saws and even since professional carpenters used speed squares as a quick saw guide for cutting 45 and 90 degree angles. The steepest pitch for a roof is 12 12 which creates a 45 degree angle and where the roof vertically rises 12 inches for every 12 inches it goes horizontally.

You can make the 20 degree cut following the set angle flip the tool over and make the complementary 70 degree cut to create a perfect 90 degrees. To measure pitch first position the hypotenuse of the square on the roof running. Set cut angle for rafter place the framing square so the blade is horizontal on the rafter and the tongue is on the rafter and draw lines. Accuracy is key here because miscalculations could lead to major overspending.

Photo 2 shows how to use the speed square to mark a 33 1 2 degree angle the same as you would need on a rafter tail for a roof with an 8 12 pitch. Screw the gauge in place.