How To Determine Roof Pitch With Framing Square

How to use a framing square and its etched on tables to figure out roof slope rafter lengths.

How to determine roof pitch with framing square.

Roof pitch affects the actual area 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. 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. The pitch of a roof is determined by the slope of the rafters in relation to the horizon. The triangle shaped square was invented in 1925 by albert swanson to provide a quick accurate method for marking rafters. 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.

A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally. Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs. Technically roof pitch is the ratio of total vertical roof height the rise to total horizontal distance from wall to wall the span. A carpenter s framing square includes some tables stamped right into the tool itself.

This angle is measured not in degrees but in inches of rise per foot of run. 5 x research source although most homeowners do not need to measure pitch it still pays to understand this term. Finding the pitch of a roof is simple with a speed square. Square guides are available at most hardware and home improvement centers.

Roof pitch is a determining factor for cost of the roof as well as the roof area and the type of materials used.