How Do You Determine The Slope Of A Roof

The example to right shows 2 different ways to determine or calculate roof pitch also called roof slope.

How do you determine the slope of a roof.

Then enter the value of the run and choose the unit of measurement from the drop down menu. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally. Example a the measurements are taken from on top of the roof. Rise run pitch where pitch is expressed in percent.

To do this you will need to write down the measurements that you have taken from the rafters. For example when a roof has a slope of 5 12 the roof is 5 inches high for every 12 inches long. Pitch tan angle where angle is the roof pitch expressed in degrees. Rafter rise run from the pythagorean theorem.

A ratio is the most common way of expressing roof pitch or roof slope but degrees are also possible. The 7 means that the roof rises 7 for every 12 it runs. The way pitch also known as roof slope is measured is rise over run. Roof slopes are measured in units of twelves.

Here are the steps to follow for the roof angle calculator. Degrees to pitch rise in run determine the area of the roof s footprint which is the area covered by the roof regardless of slope or the apparent area of the roof when you look straight down at it like from a satellite. You can measure with twelve feet or twelve yards but in this article we will use twelve inches. To accurately calculate the area of your roof you must first determine its slope or pitch.

The horizontal distance in the ratio will be 12 while the vertical distance is the measurement you took from the rafters. The slope of your roof is the ratio of the vertical distance or rise of the roof to the horizontal distance or run. So if your roof rises 4 inches for every 12 inches of horizontal length then the pitch of your roof is expressed as 4 12. First enter the value of the rise and choose the unit of measurement from the drop down menu.

Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs. For example if you find 4 inches of height with the tape measure at the 12 inch mark on the level your slope is 4 12 or 4 in 12. There s no need to simplify them. The slope of your roof is the ratio of vertical distance rise to horizontal distance run.

Simply mark a level at 12 hold it perfectly level and measure from the roof surface to your 12 mark this. How to calculate roof pitch.