Roof Felt As House Wrap

Here s what an expert had to say.

Roof felt as house wrap.

Substituting synthetic roof underlayments for housewrap after stripping the original siding from a 30 year old house and preparing to install fiber cement panels a contractor wonders if he can use a waterproof synthetic roofing underlayment instead of housewrap behind the panels. The main purpose of the sheathing wrap whether building felt or plastic housewrap is to prevent water leakage into the building structure. It is critical therefore to cover the entire shell from roof to foundation including gable ends and band joists and always to lap upper layers over lower layers shingle style to shed water. 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.

07 31 2017 07 56 pm. 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. 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. In fact there are a number of important ways roofing felt not only protects your roof but also your residence.

House wrap and felt paper when properly installed and undamaged are both weather resistant barriers wrb that create permeable and water and air resistant exterior 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. Asphalt felt tar paper the standard requirement is type 1 felt meeting astm d 226 standards. The main advantage of house wrap over felt paper is the superior strength and durability of house wrap.

Tar paper or roofing felt is put on a roof to waterproof it until the shingles are applied. Why use roofing felt paper. It s both breathable which will help solve problems with moisture and waterproof. A high quality house wrap like barricade building wrap is more resistant to ripping and tearing during installation than felt paper.

The original wrb was asphalt impregnated felt paper or tar paper the same material commonly used as an underlayment under roof shingles. After the shingles or roofing material is installed the felt is of no effect except as an insulation and it is negligible. More recently the term house wrap is usually used to describe plastic fabric wrbs such as tyvek.