How To Figure Roof Pitch With Speed Square

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How to figure roof pitch with speed square.

A speed square and level can be used to easily find the pitch of a roof. A 12 12 pitch roof has a pitch angle of 45. Roof pitch refers to the amount of rise a roof has compared to the horizontal measurement of the roof called the run. 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. Marvel at your mathematical. 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 refers to the slope which the rafter creates.

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. 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. To convert between american roofing ratios and pitch degrees follow these steps.

Divide the first part of the ratio by 12 to work out the pitch. Find the inverse tangent of the pitch to find the angle in degrees. 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. Often you express roof pitch as the ratio between the rise and the run in the form of x 12.

Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run.