Permability Of Roofing Paper

Among the most vapor permeable of exterior sheathings.

Permability of roofing paper.

Unlike asphalt felt it is made from new wood pulp rather than recycled material. The research performed indicates that nonbreathable. Permeability 14 20 5 perms. Fs 75 ap 0 82.

Grade d building papers must have a 10 minute rating under astm d779 commonly called the boat test in which a piece of building paper is folded in the shape of a boat and floated in a dish of water until it soaks through and wets a powder on top. The focus of this paper is to investigate the system performance of standard asphalt shingles and to evaluate the impact of installing nonbreathable underlayments between the shingle layer and the roof deck. At saturation marginal increase in permeability 2 8 3 4 perms. Thin profile structural sheathing.

Fs 148 sd 137. Asphalt felt is paper based and has no memory meaning once it attracts moisture by being left on the roof overnight or if it gets wet it will ripple and curl and will not lay flat once it dries. Tar paper keeps the wood beneath it dry. Some grade d pape.

Notes to the table above. Find below the technical bulletins papers standards used as sources for these perm ratings. Normally used on roofs tar paper makes a great barrier for the exterior walls of your housing building or shed. Its most common use is under stucco in the western united states.

The vapor permeance of grade d paper is similar to asphalt felt. More information more information. Fiberboard asphalt impregnated. Grade d building paper is an asphalt impregnated kraft type paper similar to the backing on fiberglass insulation.