Minimum required slope x in 12 minimum required slope degrees asphalt shingles.
Minimum roof slope foam.
The minimum pitch is typically 3 12 meaning the roof should rise 3 inches for every 12 inches of horizontal foot.
The metal roof minimum slope doesn t stray far from other building with different material.
Sprayed polyurethane foam roofs must have a design roof slope of 1 4 12 or greater 2 slope.
9 46 built up roof asphalt.
Roofing material or system.
18 43 asphalt shingles with special underlayment requirements 2 in 12.
In 12 0 25 in 12 1 19 built up roof coal tar pitch.
This means for every 12 horizontal units the roof must rise a minimum of one fourth vertical unit.
For standing seam metal roof panel systems a 1 4 12 minimum roof slope is prescribed.
Built up roofs shall have a design slope of not less than one fourth unit vertical in 12 units horizontal 2 percent slope for drainage except for coal tar built up roofs that shall have a design slope of not less than one eighth unit vertical in 12 units horizontal 1 percent slope.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
For metal panel roof systems with nonsoldered seams with applied lap sealant ibc 2018 prescribes a 1 2 12 minimum roof slope.
The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
This 1 4 12 minimum roof slope requirement also applies to spray polyurethane foam spf roof systems in new construction.