Measuring Roof Pitch With Speed 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 roof pitch with speed square.

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

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 refers to the measurement of the slope of a roof and you express this as a ratio. Read the pitch on the side of the rafter square. Place the pivot point against the shingles.

It is practical when there is not a pitch tool or angle tool available. 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.

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. Then place a torpedo level on the fat base of the rafter square and adjust the square until the level is level. Note the number on the common scale parallel with the 45 degree angle of the 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.

Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run. With a torpedo level and a speed square you can pretty accurately gauge the pitch of any roof with a gable end photo 1. This is accomplished by use of the main protractor and two specialty protractor angle guides on the inside of the tool.