How To Figure Roof Pitch With A Framing Square

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

How to figure roof pitch with a framing square.

To accurately calculate the area of your roof you must first determine its slope or pitch. 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. A carpenter s framing square includes some tables stamped right into the tool itself. Finding the pitch of a roof is simple with a speed square.

Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run. Find the unit rise say inches per foot of the roof on the top line in the framing square rafter table e g. The triangle shaped square was invented in 1925 by albert swanson to provide a quick accurate method for marking rafters. 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.

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. Fix stair gauges on the framing square to mark the pitch. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally. So if the pitch of your roof is 7 12 place one stair gauge on the vertical part of the framing square the tongue at the 7 inches 18 cm mark and place one stair gauge on the horizontal part of the framing square the body at the 12 inches 30 cm mark.

A 6 inch rise 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. 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.