How To Find The Pitch Of A Roof With A Speed Square

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

How to find the pitch of a roof with a speed square.

After finding out your roof pitch angles you can use the calculator to perform the calculations for you instead of doing them manually. If we know the roof run and rafter length we find the roof slope by calculation or we use the framing square table just below and then easily find the roof rise. A speed square will have two specialty protractor angle guides on the inside of the tool which has both common rafter angles and hip valley angles marked out. To find the pitch just place the pivot point against the shingles.

If a magazine such as finehomebuilding is going to put out an article to teach a topic it should use the proper words and definitions. 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. Measured rafter run rr 17 ft. A roof slope of 4 12 is a 1 6 pitch a 6 12 slope is a 1 4 pitch an 8 12 slope is a 1 3 pitch and so on.

The triangle shaped square was invented in 1925 by albert swanson to provide a quick accurate method for marking rafters. For example using the numbers from our roof framing square table example just above. With a torpedo level and a speed square you can pretty accurately gauge the pitch of any roof with a gable end photo 1. Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run.

The pitch tells you the amount of vertical rise in inches for every 12 in. As a matter of fact finding the pitch of a roof was the motivating factor for how this tool was invented in the first place hence it s official name the rafter square. Or 17 x 12 204 in. 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.

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. I hear read all too often this misuse and usually ignore it.