Divide the first part of the ratio by 12 to work out the pitch.
How to determine the pitch of your roof.
After measuring the slope estimate the roof pitch by dividing the slope by 2.
Check your results with the omni roof pitch calculator.
Climb up on your roof.
Knowing the pitch of your roof is useful when designing an addition installing skylights or cutting new rake boards.
How to measure roof pitch.
Place the end of your level the 0 inch point of your 12 marking against the roof surface.
To measure the roof pitch you ll need an 18 or 24 inch level a tape measure and a pencil.
After finding out your roof pitch angles you can use the calculator to perform the calculations for you instead of doing them manually.
If you can t get to your attic you can measure slope on your rooftop as long as it s safe to go up there.
Find the inverse tangent of the pitch to find the angle in degrees.
A 12 12 pitch roof has a pitch angle of 45.
To convert between american roofing ratios and pitch degrees follow these steps.
This is the amount your roof inclines in a 1 foot span or the pitch.
Hold the level straight and level bubble centered and then measure the vertical distance down from the your 12 mark on the level down to the roof.
The easiest way to do this is by accessing a rafter in your attic if you can.
Here s an easy safe way to determine the pitch from inside your attic.