Finding Roof Pitch With Framing Square

A carpenter s framing square includes some tables stamped right into the tool itself.

Finding roof pitch with framing square.

How to use a framing square and its etched on tables to figure out roof slope rafter lengths. Roof pitch or slope is a measure of vertical rise to horizontal run expressed in inches per foot. Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs. This article explains how to make quick use of a framing square and its imprinted data to get some basic roof measurement data like roof pitch or slope rafter lengths and end cuts.

Find the unit rise say inches per foot of the roof on the top line in the framing square rafter table e g. Finding the pitch of a roof is simple with a speed square. The easiest way to do this is by accessing a rafter in your attic if you can. After measuring the slope estimate the roof pitch by dividing the slope by 2.

A 12 in 12 pitch is a steep 45 degree angle roof. The roof pitch is important in determining the appropriate installation method and how much roofing material will be needed. The triangle shaped square was invented in 1925 by albert swanson to provide a quick accurate method for marking rafters. A 6 inch rise per foot.

See the image below for more explanation on rise run and pitch. Roof pitch is used to describe the slope or angle of the roof. If you can t get to your attic you can measure slope on your rooftop as long as it s safe to go up there. Before you calculate roof pitch you ll need to measure the slope of your roof.

Also known as a steel square the johnson framing square is a handy tool for carpentry. It can also be used as a straight edge finding and establishing right angles and marking cut off work on widestock. How to find roof slope rafter length on a framing square how would we use our framing square to measure or to calculate the slope and rafter lengths of this historic herefordshire u k.