How To Determine Roof Pitch With A Speed Square

Leah answers a viewer s question about how to calculate the pitch of a roof on a structure.

How to determine roof pitch with a speed square.

Read the pitch on the side of the rafter square. Extend it upward so it is perpendicular to the level. Marvel at your mathematical. Measure with a speed square a speed square and level can be used to easily find the pitch of a roof.

With a torpedo level and a speed square you can pretty accurately gauge the pitch of any roof with a gable end photo 1. Often you express roof pitch as the ratio between the rise and the run in the form of x 12. Measure the roof pitch with a speed square. Use the torpedo level to make a plumb mark on the straightedge.

Hold the 0 mark of the tape measure against the roof. Place the straightedge on the shingles in a direction perpendicular to the gutter. A 12 12 pitch roof has a pitch angle of 45. 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.

The triangle shaped square was invented in 1925 by albert swanson to provide a quick accurate method for marking rafters. Measure the vertical distance from roof to level. Leah s recommended tools for beginner diy ers. Divide the first part of the ratio by 12 to work out the pitch.

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. Finding the pitch of a roof is simple with a speed square. Find the inverse tangent of the pitch to find the angle in degrees.

Place the pivot point against the shingles. 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. Roof pitch refers to the slope which the rafter creates. Then place a torpedo level on the fat base of the rafter square and adjust the square until the level is level.