Measuring Roof Pitch With Speed Square

Finding the pitch of a roof is simple with a speed square.

Measuring roof pitch with speed square.

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. A speed square aka rafter square or triangle square is a measuring multitool. Made of steel aluminum or plastic this common carpenter s tool combines a ruler a try square a protractor a line scribing tool a common width board ripping guide and a saw guide for making accurate 90 and 45 cuts with a hand or circular saw. This is a way of measuring the degree of steepness of the roof.

Also measure the length of half of the roof from one side of the ridge beam to the. The number of inches that the roof rises vertically for every foot of roof. The pitch of the roof is a ratio. How to use a rafter angle square for roof pitch.

Holding the level and speed square level locate the measurement on the speed square where it meets the bottom edge of the rafter to find the angle of the roof in degrees. Find a common rafter angled with the pitch of the roof. 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.

Before miter saws and even since professional carpenters used speed squares as a quick saw guide for cutting 45 and 90 degree angles. Mark along the outside edge of the rafter angle square for your angled cut. Roof pitch refers to the measurement of the slope of a roof and you express this as a ratio. If you are measuring by pitch as opposed to angles line up the desired pitch as indicated by the common edge on the same edge as the pivot.

Roof pitch or slope is a measure of vertical rise to horizontal run expressed in inches per foot. 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. The triangle shaped square was invented in 1925 by albert swanson to provide a quick accurate method for marking rafters. It is often compared to slope but is not exactly the same.