High pitched roofs often need extra fasteners and their pitch can be as high as 21 12.
Roof pitch for lean to.
Enter this measurement into the calculator and select a roof pitch and the length of the rafter will automatically returned along with the rise.
However you can only use this pitch with built up roofing or specialized synthetic roofing.
Regular asphalt shingles that are rated for 4 in 12 roof slopes can be installed on lower slope roofs by simply installing a waterproof membrane under them.
Many roofing shingles do not allow applications onto roofs at this pitch.
The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.
Conventional roofs are the easiest to construct and you can walk on them safely.
You can also calculate roof pitch even without using a roof slope calculator.
More commonly roll on membranes such that use heat to bond seams together is used as a roofing material.
They have a pitch ranging from 4 12 to 9 12.