Measuring Roof Pitch With Speed Square

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.

Measuring roof pitch with speed square.

This is the basic method to find the pitch of a roof. 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. A speed square and level can be used to easily find the pitch of a roof. It is often compared to slope but is not exactly the same.

The hash marks with corresponding numbers between 1 and 30 refer to the roof s rise angle. Read the pitch on the side of the rafter square. Then place a torpedo level on the fat base of the rafter square and adjust the square until the level is level. 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.

With a torpedo level and a speed square you can pretty accurately gauge the pitch of any roof with a gable end photo 1. 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. It is practical when there is not a pitch tool or angle tool available. Roof pitch refers to the measurement of the slope of a roof and you express this as a ratio.

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. Place the pivot point against the shingles. The pitch of the roof is read where the bottom of the rafter crosses this scale. Do this for every face of differing size.

Note the number on the common scale parallel with the 45 degree angle of the square. 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. 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.