Using Roofing Felt On Walls

Also known as tar paper roofing felt originated in finland in the 1870 s as a waterproofing underlayment for roofs.

Using roofing felt on walls.

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. Roofing felt prevents the deck from being exposed to the elements before or while the shingles are being applied. 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. The wood oriented strand board osb that s nailed to the studs can have water vapor condense and become liquid water inside the wall.

Hold the felt roll upright against the exterior wall at one edge. Today glass fiber or polyester fabric may be used instead of paper. Yes felt paper can cause wood rot if it begins to block water vapor from getting to the outside air. Use a heavy duty felt for long term weatherproofing.

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. 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. 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. 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.

It improves look and uniformity. Felt comes in either 15 pound or 30 pound ratings. If the heads of any nails protrude pound them into the wall using a hammer. Use a flat pry bar to remove any staples nails or other fasteners from the wall where you re installing the felt paper.

First paper was impregnated with coal tar. 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. This water is what fuels fungi that cause wood rot. Also once wet the permeability asphalt felt actually rises from 5 to as much as 60 further promoting rapid drying.