Low Slope Roof Asphalt Shingles

The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.

Low slope roof asphalt shingles.

Asphalt shingles continue to be the most widely installed roof covering option in north america. The arma s residential manual for asphalt roofing recommends that asphalt shingles on low slope roofs be applied over a nonperforated single layer of adhesive backed bituminous membrane installed to the manufacturer s specifications or over a double layer of asphalt impregnated felt paper. The acceptable underlayment installation options for low slopes are described in the canadian standards association asphalt shingle application standard csa a123 51 as follows. This low slope application requires a double layer of 15 felt underlayment cemented together for a distance extending from the eaves up to a point 24 inches inside the interior wall line of the building.

They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends. What is the minimum slope for an asphalt shingle roof. Because of the non absorbent nature of asphalt the shingles themselves provide an element of waterproofing which is why they work well for low slopes. The usual slope for asphalt shingles is a 4 or greater rise for every horizontal foot of run.

A 3 per foot slope is considered low but may be acceptable if a double layer of felt is used. Cover the entire low sloped roof area with a self adhered modified bituminous membrane that will act as an ice and water.