Roof Felt 15 Lb Vs 30 Lb

No 15 felt and no.

Roof felt 15 lb vs 30 lb.

30 felt is typically thicker stronger and may be less prone to tearing or ripping off during installation or weather events. 30 was used as a base sheet for built up roofing and underlayment under slate tile and shingles. 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. 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.

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. 15 felt or 30. Felt roofing underlayment is typically available in two types.

The best weight for roofing felt is the 30 pound product because it provides thicker and stronger footing for roofers that does not tear out especially on steep roofs where footing is critical. 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. The difference is obvious once you see them together. 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.

30 pound gets to oily in the summer and smears to easily. 15 pounds with enough tacks or boards is plenty good enough. 15 came perforated for use as a ply sheet for built up roofing use and non perforated. A shingle underlayment is used to protect roof structures and the interior from water penetration.

Felt is an asphalt saturated organic felts designed for use as an underlayment with asphalt shingles in commercial and residential applications. Twice as much work carrying paper with 30 too. Because it s thicker and stronger. Fifteen pound felt has a perm rating of about 5 although this number can rise in high humidity conditions.

Plywood or osb roof deck so 15 20 or 30 will work for any shingle roof the type i recommend depends on roof slope.