How to Identify Roof Pitch

Roof "pitch" is the measurement of the incline or slope of a roof. You need to know the pitch to calculate the size of a roof and determine how much material you'll need to shingle the roof or do roofing repairs. Often cited as 4/12 or 7/12, the pitch tells the rise of the roof. For instance, a roof with a 4/12 pitch rises 4 inches for every foot (every 12 inches) up to the peak. The "run" is the length of the roof from one gable end to the other. Contractors use pitch, rise and run to properly estimate a roofing job.

Carpenter's level
Tape measure
Ladder

Instructions

- 1
  Secure a ladder next to the house in a safe manner. Generally, it is the front or rear of the house where you need to determine roof pitch. Protect the gutters when placing the ladder.
- 2
  Place a carpenter's level on the roof, with one end toward the roof edge and the other end toward the roof peak. You need 12 inches of the level on the roof for an accurate measurement. Remember that rise is calculated in 12-inch increments.
- 3
  Raise the end of the level closest to the roof edge until the bubble is centered. Measure 1 foot from where the level rests on the roof, and mark the level. Then measure the distance from the roof to the bottom of the level, at that 1-foot mark.
- 4
  Include the measurement of roofing material into your calculations to determine the true pitch of the roof. For example, if you have a terra-cotta roof and the tiles are 2 inches high when laid, then you must add 2 inches into your calculations.
- 5
  Write the measurement as the rise over the run, or the inches measured by the 12 inches of roofing. For instance, if your measurement was 3 inches, then the pitch is written as 3/12.

How to: Roofing Angles

Roofing Material for Buildings

Roof Repairs