How Do I Figure Out Roof Pitch

Check the surface of the.

How do i figure out roof pitch.

Rise run pitch where pitch is expressed in percent. Take a measurement of 12 inches using a level. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally. Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs.

Position your level against the roof until the bubble of the vial sits between two lines. Rafter rise run from the pythagorean theorem. For example if the roof rises 4 feet and the span is 16 feet twice the run then the pitch is 4 16 or 1 4. One method to find the pitch is to climb on the roof and measure the rise for a 12 run.

For more complex roofs you may need to calculate it section by. First measure 12 inches from one end of the level and make a mark. On the roof hold the level perfectly level and measure the height from the roof to the level 12 inches away from where the level touches the surface this will be the rise. Pitch tan angle where angle is the roof pitch expressed in degrees.

Before taking any measurements you must first confirm that it s safe to walk on your roof. How to calculate roof pitch. For a simple gable roof the span wall to wall will be twice the size of the run wall to ridge horizontally. Pitch is the incline of the roof represented as the ratio of rise to the span twice the run.

Take the measurement of the vertical. You ll need a level that is 12 or longer and a tape measure. A 12 in 12 pitch is a steep 45 degree angle roof. See the image below for more explanation on rise run and pitch.

For a roof with the ridge above one wall the span is the same as the run.