How To Figure Roof Pitch With Speed Square

A speed square and level can be used to easily find the pitch of a roof.

How to figure roof pitch with speed square.

The triangle shaped square was invented in 1925 by albert swanson to provide a quick accurate method for marking rafters. 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. It is often compared to slope but is not exactly the same. Set the level on the edge of the speed square as shown below then place the heel of the speed square on a rafter or gable edge of the roof.

Check your results with the omni roof pitch calculator. Find the inverse tangent of the pitch to find the angle in degrees. Before miter saws and even since professional carpenters used speed squares as a quick saw guide for cutting 45 and 90 degree angles. Marvel at your mathematical.

In the united states a run of 12 inches 1 foot is used and pitch is measured as the rise of the roof over 12 inches. Finding the pitch of a roof is simple with a speed square. Because of its compact size it is frequently used as a saw guide when cutting framing members as well as a layout tool for quick 45 and 90 degree cuts. Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run.

To convert between american roofing ratios and pitch degrees follow these steps. Roof pitch refers to the amount of rise a roof has compared to the horizontal measurement of the roof called the run. Often you express roof pitch as the ratio between the rise and the run in the form of x 12. A 12 12 pitch roof has a pitch angle of 45.

Roof pitch refers to the slope which the rafter creates.