How To Estimate Roof Pitch

Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs.

How to estimate roof pitch.

You can use the following equations to find the length of the rafter and the slope. To measure the roof pitch you ll need an 18 or 24 inch level a tape measure and a pencil. How roof pitch is calculated to accurately calculate the area of your roof you must first determine its slope or pitch. Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run.

Generally roof pitch is calculated from the same formula that describes a right triangle. You ll need a level that is 12 or longer and a tape measure. Rise run pitch where pitch is expressed in percent. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally.

First measure 12 inches from one end of the level and make a mark. This is very useful information for many purposes especially for roof framing the slope sometimes called pitch is calibrated on speed squares. 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. Then in the attic place the end of the level against the bottom of a roof rafter and hold it perfectly level.

Express roof pitch as the ratio of the amount of the vertical rise of a roof or rise over the corresponding horizontal distance or run you write the pitch assuming a run of 12 inches thus the ratio would describe how much a roof rises for each foot of the run. Divide the slope by two to get the pitch. How to calculate roof pitch. Roof pitch calculator results explained slope the slope of a roof is represented as x 12 where x is the number of inches in rise for every 12 inches of run.

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. Rafter rise run from the pythagorean theorem. One method to find the pitch is to climb on the roof and measure the rise for a 12 run. If you do need to calculate the pitch an estimate or shortcut is usually more practical than measuring the roof s overall dimensions.

For a simple gable roof the span wall to wall will be twice the size of the run wall to ridge horizontally.