How Tofind Slope On A Roof

Confirm the roof is safe to walk on.

How tofind slope on a roof.

If you do know the roof slope in degrees then all you have to do is find the secant using a scientific calculator. The slope of a roof often referred to as the pitch is determined by rise over run the roof s vertical rise in inches for every twelve inches of horizontal length the run. How do you calculate the slope of a roof. To find the slope in degrees you divide the rise by the run and find the inverse tangent of the result.

Locate the level s 12 inch mark. So a roof with four inches of rise every 12 inches horizontally run would have a slope of 4 12 sometimes displayed as 4 12. The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7. Use a level against the underside of the rafter you re measuring to get the most accurate value.

Measure 12 inches on a carpenter s level. The minimum roof pitch for shedding snow is around 30 or a 6 12 or 7 12 slope although this is not a definite as the material of your roof the direction of the snow and wind are some factors that can affect whether or not snow will slide as roofs of as little as 10 have been reported to shed snow. First convert the pitch to a slope. To find the angle of a roof in degrees convert the pitch to a slope then convert to degrees by finding the arc tangent of the slope.

Another way of stating this is that the roof has a rise of 5 and a run of 12. To do this simply convert the rise and run as a fraction to a decimal form eg. But you still need to have the rise and the run to find the degree angle if you don t already know it. How to convert roof pitch to degrees.

Rise run rise run slope. Roof slopes are measured in units of twelves. For example if the roof slope angle is 45 then sec 45 1 414213. The most precise way to find the roof s slope is by measuring it from the underside.

Many levels are equipped with a ruler on. Figuring this is simple. Measuring slope from the roof surface 1. Access one of the rafters then take.

Climb up a ladder without your tools to take a look at the roof surface. You can measure with twelve feet or twelve yards but in this article we will use twelve inches.