How To Find The Pitch Of A Roof With A Framing Square

Pitch measurement method 1.

How to find the pitch of a roof with a framing square.

Pitch of hips the pitch is based on a 12 run on the framing square. Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run. 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 most precise way to find the roof s slope is by measuring it from the underside.

For example a 12 12 roof pitch would have 11 1 16 12 pitch hips. Directly below the 6 inch mark on the framing square read the required rafter length 13 42 per foot of run for a 6 inch rise 6 in 12 roof. To calculate the required rafter length multiply the total run length half the building width plus the width that the roof is to overhang the house wall by this number 13 42. 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.

On a ladder beside the roof place the level a foot or so up the roof hold it level and measure from the 12 inch mark on the level s bottom straight down to the roof. Finding the pitch of a roof is simple with a speed square. Locate the level s 12 inch mark. 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. The swanson speed square is a popular tool with most carpenters. Use a level against the underside of the rafter you re measuring to get the most accurate value. 8 inches and you have an 8 in 12 pitch.

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 carpenter s framing square includes some tables stamped right into the tool itself. How to use a framing square and its etched on tables to figure out roof slope rafter lengths. Access one of the rafters then take the measurement this way.