Measuring from the underside of the roof is usually the most accurate way to find the slope since there is no roofing material to make an uneven surface.
How to measure roof pitch slope.
Rise run pitch where pitch is expressed in percent.
Step 1 access a rafter.
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.
How to obtain roof pitch or slope by using the rafter tables on a framing square measuring the roof slope pitch or rise and run is easy if you ve got a tape measure and more accurate still if you ve also got a level on hand.
How to calculate roof pitch.
Use a level against the underside of the rafter you re measuring to get the most accurate value.
You can use the following equations to find the length of the rafter and the slope.
Place one end of a carpenter s level against the underside of the.
How to determine or calculate roof pitch or roof slope roof pitch calculator is determined by the number of inches it rises vertically for every 12 inches it extends horizontally.
Access one of the rafters then take the measurement this way.
Rafter rise run from the pythagorean theorem.
Generally roof pitch is calculated from the same formula that describes a right triangle.
Any of the following will give you a good measurement 1 x research source a rafter in the attic.
A barge rafter at the side of the gable step 2 position a level against the underside of the rafter.
The most precise way to find the roof s slope is by measuring it from the underside.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
The overhang of a rafter at the end of the roof.