Low Slope Roof Shingles

Some building codes allow as low as a 2 slope with asphalt shingles if additional steps are taken.

Low slope roof shingles.

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. As well a slope of 4 12 is most commonly considered the lowest slope for standard shingle installations. 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. A 3 per foot slope is considered low but may be acceptable if a double layer of felt is used.

The acceptable underlayment installation options for low slopes are described in the canadian standards association asphalt shingle application standard csa a123 51 as follows. Low slope roofing shingles. Shingles that are not self sealing must be hand sealed with asphalt roofing cement. 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.

They typically had different underlayment recommendations for low slope roofs 2 12 to 4 12 pitches but that was about it. The usual slope for asphalt shingles is a 4 or greater rise for every horizontal foot of run. 3 tab shingles versus laminated shingles for low slope roof. Low slope roofs present a challenge where water is concerned.

However those naysayers would be wrong.