Roof Felt 15 Lb Vs 30 Lb

Preparation sweep roof deck to remove.

Roof felt 15 lb vs 30 lb.

Fifteen pound felt has a perm rating of about 5 although this number can rise in high humidity conditions. 15 pounds with enough tacks or boards is plenty good enough. 30 pound gets to oily in the summer and smears to easily. 15 felt or 30.

The main advantage of using felt roofing underlayment is cost. 30 pound roofing felt it is not paper it s made from either fiberglass or polyester that s been bound together with asphalt costs the same per roll as 15 pound felt but there are 216 square. Plywood or osb roof deck so 15 20 or 30 will work for any shingle roof the type i recommend depends on roof slope. In my opinion felt paper is a vapor barrier plus keeps the oils in the shingles from leaching out and into the wood substrate i e.

Felt roofing underlayment is typically available in two types. 15 came perforated for use as a ply sheet for built up roofing use and non perforated. Felt is an asphalt saturated organic felts designed for use as an underlayment with asphalt shingles in commercial and residential applications. 30 was used as a base sheet for built up roofing and underlayment under slate tile and shingles.

The difference is obvious once you see them together. No 15 felt and no. In the old days common felt was 15 lb felt and 30 lb felt and a roll of the first held 4 squares and weighed 60 lbs while a roll of the second held 2 squares and weighed 60 lbs. Felt description united 15 lb.

Roofing felt comes in large rolls and installs in horizontal rows starting at the lower edge of the roof with each subsequent row overlapping the previous one. Because it s thicker and stronger. 30 pound roofing felt it is not paper it s made from either fiberglass or polyester that s been bound together with asphalt costs the same per roll as 15 pound felt but there are 216 square. Twice as much work carrying paper with 30 too.

Thirty pound felt is more resistant to damage during installation of the roof covering material and will protect the roof longer if it should somehow become exposed to weather.