Using Roofing Felt On Walls

Felt comes in either 15 pound or 30 pound ratings.

Using roofing felt on walls.

When and why condensation occurs inside buildings explains the problems caused by excessive indoor condensation explains how moisture enters building wall and ceiling cavities and summarizes the best approaches to prevention of indoor moisture and condensation problems. For a more permanent roof coverage use roll roofing. Later asphalt was used in the manufacture of roofing felt. Yes felt paper can cause wood rot if it begins to block water vapor from getting to the outside air.

Hold the felt roll upright against the exterior wall at one edge. First paper was impregnated with coal tar. Then install vertical nailers over the wrapped sheathing and attach the panels to the nailers which will create an air space between the panels and the wall sheathing. First cover the sheathing with asphalt felt or a nonperforated housewrap like tyvek or typar which will protect the sheathing from moisture but also allow the wall assembly to breathe.

Liberally staple the edge of the felt to the wall with a staple gun then proceed to unroll the felt along the wall. The wood oriented strand board osb that s nailed to the studs can have water vapor condense and become liquid water inside the wall. Also once wet the permeability asphalt felt actually rises from 5 to as much as 60 further promoting rapid drying. If water leaks into a wall the asphalt felt will tend to soak up the excess water as will lumber and wood products like plywood helping to store the water until drying conditions improve.

Today glass fiber or polyester fabric may be used instead of paper. The use of roofing felt or 15 pound felt as a building house wrap or vapor barrier and the permeability moisture problems and indoor condensation problems that may occur vapor barriers and condensation in buildings. Use a flat pry bar to remove any staples nails or other fasteners from the wall where you re installing the felt paper. Because your roof deck might not lie perfectly straight or flat a layer of roof paper gives an even uniform surface upon which you can install your shingles.

If the roof felt tears cut a piece large enough to cover the tear with lots of overlap slip the top under the next lap. Roofing felt prevents the deck from being exposed to the elements before or while the shingles are being applied. This water is what fuels fungi that cause wood rot. Also known as tar paper roofing felt originated in finland in the 1870 s as a waterproofing underlayment for roofs.