The recommended minimum roof pitch for shingles is 2 12 or simply two units of vertical rise to every twelve units of horizontal span.
Minimum roof pitch for felt shingles.
9 46 built up roof asphalt.
The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
It is important for shingle roofs to function properly and one method of ensuring that this is achieved is to observe the pitch requirements for the shingles.
In 12 0 25 in 12 1 19 built up roof coal tar pitch.
Felt tiles or roofing shingles.
Roofing material or system.
Roofing shingles are laid starting at the bottom of the roof.
Asphalt shingle manufacturers will warrant shingles installed on roof slopes as low as 2 12 when these special installation procedures are followed.
Let us recap on the minimum roof pitch required for each type of roofing material.
The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.
What is the minimum pitch slope of an asphalt shingle roof.
Asphalt felt paper that is tacked to the roof sheathing.
Shingles of all types need to have a slope to function properly.
Metal roof shingles require a minimum roof pitch of 3 12 or greater.
That works out to about nine degrees if that works better for you.
The asphalt shingle manufactures recommend that you install asphalt shingles on a recommended minimum of 4 in 12 or greater however most manufactures will warrant their shingles down to a 2 in 12 pitch if the recommended installation method is used.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
Minimum required slope x in 12 minimum required slope degrees asphalt shingles.
Clay and concrete tile requires a minimum roof pitch of 2 1 2 12 or greater.
The shingles overlap each other by about 150 mm at the ridge a capping piece is used.
Using felt tiles is the next step up in quality.
For the rest of the roof slope the felt underlayment must be installed with a 19 inch top lap and a 12 inch side lap providing double coverage of the felt layer.
The minimum requirement is 2 12.
For roof slopes of four units vertical in 12 units horizontal 33 percent slope or greater underlayment shall be a minimum of one layer of underlayment felt applied shingle fashion parallel to and starting from the eaves and lapped 2 inches 51 mm fastened only as necessary to hold in place.
All asphalt shingle roofs with a pitch of 4 12 or more have an underlayment of 15 lb.
18 43 asphalt shingles with special underlayment requirements 2 in 12.
They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.
But shingle roofing is not watertight in the sense that standing water or wind driven water on a low slope roof can work its way up between the laps which is the reason for the minimum 2 12 slope.
Rough cost m 2.
