How To Measure Roof Pitch Slope

Rise run pitch where pitch is expressed in percent.

How to measure roof pitch slope.

Rafter rise run from the pythagorean theorem. Generally roof pitch is calculated from the same formula that describes a right triangle. But did you know that simple data already printed on your framing square can give key roof slope and rafter data. Also referred to as roof slope or roof slant so what does the 7 12 in the example to the right mean.

Locate the level s 12 inch mark. The most precise way to find the roof s slope is by measuring it from the underside. 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.

Use a level against the underside of the rafter you re measuring to get the most accurate value. Place one end of a carpenter s level against the underside of the. 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. You can use the following equations to find the length of the rafter and the slope.

Step 1 access a rafter. 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. 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.

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.