Measuring Roof Pitch With Speed Square

A speed square and level can be used to easily find the pitch of a roof.

Measuring roof pitch with speed square.

Measuring pitches part of the speed square s role as a protractor and its original mission as a tool is in quickly finding common and uncommon rafter angles for the pitches on roofs. Then place a torpedo level on the fat base of the rafter square and adjust the square until the level is level. Read the pitch on the side of the rafter square. 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.

Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run. It is often compared to slope but is not exactly the same. Set the level on the edge of the speed square as shown below then place the heel of the speed square on a rafter or gable edge of the roof. This is accomplished by use of the main protractor and two specialty protractor angle guides on the inside of the tool.

For a trapezoidal roof add the lengths of the bottom edge and ridge together divide the sum by 2 and multiply the number you get by the measurement of the line running between the two edges. Although there s isn t any standard pitch of a roof used on all kinds of sloped roofs you can determine the range of pitches by using a roof angle calculator and by considering factors like the local climate and roofing materials. The hash marks with corresponding numbers between 1 and 30 refer to the roof s rise angle. 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 is not difficult and is a. It is practical when there is not a pitch tool or angle tool available. Do this for every face of differing size. The pitch of the roof is read where the bottom of the rafter crosses this scale.

Note the number on the common scale parallel with the 45 degree angle of the square. Place the pivot point against the shingles. 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.