Low Slope Roof Shingles

Low slope roofing shingles.

Low slope roof shingles.

They typically had different underlayment recommendations for low slope roofs 2 12 to 4 12 pitches but that was about it. If you have a low slope roof but would love to have a shingled look rather than other solutions like rolled sheet roofing you are in luck. As well a slope of 4 12 is most commonly considered the lowest slope for standard shingle installations. And by the way the manufacturers instructions i reviewed for the shingles i was interested in buying described installations down to a 2 12 pitch.

However those naysayers would be wrong. 3 tab shingles versus laminated shingles for low slope roof. The usual slope for asphalt shingles is a 4 or greater rise for every horizontal foot of run. Low slope roofs present a challenge where water is concerned.

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. Most manufacturer and industry recommendations require or at the very least recommend special underlayment or other considerations on roofs between 2 12 and 4 12. The acceptable underlayment installation options for low slopes are described in the canadian standards association asphalt shingle application standard csa a123 51 as follows. Some building codes allow as low as a 2 slope with asphalt shingles if additional steps are taken.

Cover the entire low sloped roof area with a self adhered modified bituminous membrane that will act as an ice and water.