How To Determine Roof Pitch With Framing Square

This data will tell us the required rafter length for a roof of a given pitch or slope.

How to determine roof pitch with framing square.

The triangle shaped square was invented in 1925 by albert swanson to provide a quick accurate method for marking rafters. This angle is measured not in degrees but in inches of rise per foot of run. How to use a framing square and its etched on tables to figure out roof slope rafter lengths. Finding the pitch of a roof is simple with a speed square.

A carpenter s framing square includes some tables stamped right into the tool itself. 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 only tools needed to determine the pitch of any roof is a ladder a torpedo level a speed square and a straightedge. 5 x research source although most homeowners do not need to measure pitch it still pays to understand this term.

Roof pitch is a determining factor for cost of the roof as well as the roof area and the type of materials used. Square guides are available at most hardware and home improvement centers. 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. Framing square guides are small inexpensive metal attachments to the framing square that are locked in position on the square s edges at the pitch and run dimensions to define the roof angle and make the repeated marking of the rafters much more efficient.

To accurately calculate the area of your roof you must first determine its slope or pitch. A long standing use of the framing square that is missed by many new carpenters is the rafter table imprinted right on the framing square itself. It affects walkability as well as drainage and roofs in areas of high rain or snowfall tend to have steeper pitches. The pitch of a roof is determined by the slope of the rafters in relation to the horizon.

Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs.