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.
Shingle low pitch roof.
Although surprisingly there was only one leak in the old roof.
1 cover the entire surface with a self adhesive flashing membrane such as grace ice water shield there are many equivalent products.
However those naysayers would be wrong.
According to the asphalt roofing manufacturers association 301 348 2002 asphalt shingles can be applied to a roof with a pitch as shallow as 2 in 12.
Then apply standard asphalt shingles over the membrane.
The membrane will outlast the shingles and seal around all nail penetrations.
However roofing over old shingles should be done only when the existing shingles and the roof underneath are in good shape.
With respect to shingle application roof slopes from 2 12 to less than 4 12 18 5 are called low slope roofs while roof slopes of 4 12 or greater are called normal or standard slopes.
Reshingling a low slope roof and a few things not to do this article covers reshingling a low sloped roof and a few things you should avoid when shingling such a roof.
Former senior editor roe a.
Low slope roofs present a challenge where water is concerned.
Visiting my sister marlene in thunder bay this summer 2012 there was as usual a project like every other time.
Some will argue that shingles shouldn t be used for low pitch roofs at all.
Asphalt shingles should never be applied to roof slopes below 2 12 2 of vertical rise for every 12 of horizontal run or 9 5.