How To Figure Roof Pitch With Speed Square

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.

How to figure roof pitch with speed square.

Often you express roof pitch as the ratio between the rise and the run in the form of x 12. You can assess this in two ways either as the roof pitch angles which the rafters make with the horizontal or the proportion between the run and the rise of the roof. Find the inverse tangent of the pitch to find the angle in degrees. It is often compared to slope but is not exactly the same.

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. Finding the pitch of a roof is simple with a speed square. A 12 12 pitch roof has a pitch angle of 45. The triangle shaped square was invented in 1925 by albert swanson to provide a quick accurate method for marking rafters.

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. 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. 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.

A speed square and level can be used to easily find the pitch of a roof. Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run. Divide the first part of the ratio by 12 to work out the pitch. Marvel at your mathematical.

To see how pitch impacts the look of a garage and changes cost click the design center button on our pole barn kits page.