Minimum Pitch For Roofing Felt

Asphalt shingles continue to be the most widely installed roof covering option in north america.

Minimum pitch for roofing felt.

They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends. In 12 0 25 in 12 1 19 built up roof coal tar pitch. Asphalt saturated felt starting at the eaves and lapping upper courses over lower by a minimum of 2 inches. This means for every 12 horizontal units the roof must rise a minimum of two and one half vertical units.

The recommended minimum roof pitch for shingles is 2 12 or simply two units of vertical rise to every twelve units of horizontal span. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. The overlapping felt creates a secondary barrier for moisture and wicks water away from the shingles above and the sheathing below. If 4 12 and above is normal and 2 12 is minimum what about properties with roofs in between the two such as a 3 12 pitched roof.

Use a pitch of more than ten degrees for more efficient rain protection. 18 43 asphalt shingles with special underlayment requirements 2 in 12. 9 46 built up roof asphalt. What is the minimum slope for an asphalt shingle roof.

Roofing felt is required to overlap 2 inches over the lower felt course. The minimum pitch is typically 3 12 meaning the roof should rise 3 inches for every 12 inches of horizontal foot. However it is regrettable that many installers usually ignore this requirement due to the desire for a quick installation process. Minimum required slope x in 12 minimum required slope degrees asphalt shingles.

The standard of lower pitch actually ranges between 1 12 to 5 12. A pitch of 10 degrees or less is typically regarded as a flat roof. Therefore a 2 inch overlap provides redundancy at the edges where the barrier is weakest. The metal roof minimum slope doesn t stray far from other building with different material.

Normal shingle installation is allowed for all roofs with a pitch of 4 12 and above. Normal roof slope for typical installation. Clay and concrete roof tiles can only be installed on roof slopes of 2 1 2 12 or greater. Minimum roof slope roof pitch r905 3 2.

On roofs with a slope of 4 12 or greater use a single layer of 15 lb. In the case of a shed roof a layer of roofing felt usually offsets the porosity of the wood. Vertical joints should lap a minimum of 4 inches and be offset by at least 6 feet in successive rows see figure 2 2 at left.