Rise Over Run Roof

The horizontal change in distance or the horizontal distance covered by an un supported rafter or truss.

Rise over run roof.

The rise is the distance from the top of the roof to the bottom. Pitch is written assuming a run of a foot or 12 inches so the ratio describes how much the roof rises for every foot of its run. In roof pitch calculator pitch value can be obtained by dividing n by 12 and divide s by the answer. A 3 in 12 roof rises 3 for every 12 of run.

The run is the distance from the outside of the wall to the inside of the ridge. That s the same as a 14 degree slope or a 25 slope. The same pitch is also sometimes written as 4 12 4 in 12 or 4 over 12. For example a roof that rises 4 inches for every 12 inches of run has a 4 12 pitch.

3 of rise per 12 of run is the same as 1 of rise per 4 of run or 1 4 25. Simply locate a roof rafter board place the end of the level against the bottom edge and measure from the 12 inch mark vertically to the bottom edge of the rafter. Total roof rise or change in elevation for a 38 degree sloping roof angle t with one giant rise or step of 7 8 feet to the center of the attic y 2 would have total a run x 2 of 10 feet. For example if you measure 4 inches the pitch of your roof is 4 12.

Other than the 45 roof slope which is 12 in 12 none of the standard roof pitches 5 in 12 6 in 12 etc are equal to a whole degree. This will give you the rise over run or pitch. On a 38 degree sloping roof angle t each individual vertical rise of 9 4 y 1 would have a horizontal run x 1 of 12 inches.