Permability Of Roofing Paper

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.

Permability of roofing paper. Tar paper keeps the wood beneath it dry. At saturation marginal increase in permeability 2 8 3 4 perms. Find below the technical bulletins papers standards used as sources for these perm ratings. 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.

The vapor permeance of grade d paper is similar to asphalt felt. Its most common use is under stucco in the western united states. Notes to the table above. Thin profile structural sheathing.

Fiberboard asphalt impregnated. Necessary to protect the roof sheathing from moisture within the home. Grade d building paper is an asphalt impregnated kraft type paper similar to the backing on fiberglass insulation. Permeability 14 20 5 perms.

When then used with asphalt shingles especially traditional 3 tab shingles it sometimes telegraphs the ripples through the finished product. More information more information. Fs 75 ap 0 82. Tar paper has been time tested as a weather barrier.

Normally used on roofs tar paper makes a great barrier for the exterior walls of your housing building or shed. 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. Fs 148 sd 137. The research performed indicates that nonbreathable.