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 as house wrap.
A high quality house wrap like barricade building wrap is more resistant to ripping and tearing during installation than felt paper.
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.
Here s what an expert had to say.
Drive plenty of staples especially if it is windy in your area.
Working with a helper install the bottom piece of felt so it extends 1 or 2 inches below the sill.
Underlayment must also act as a secondary weather barrier in case the roof fails.
It s both breathable which will help solve problems with moisture and waterproof.
How to do it install bottom piece.
The first goal of roofing underlayment is to keep the roof deck dry before installation of the metal roofing material.
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.
More recently the term house wrap is usually used to describe plastic fabric wrbs such as tyvek.
Drive staples and trim.
The main purpose of the sheathing wrap whether building felt or plastic housewrap is to prevent water leakage into the building structure.
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 original wrb was asphalt impregnated felt paper or tar paper the same material commonly used as an underlayment under roof shingles.
If you will be attaching.
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.
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.
Asphalt felt tar paper the standard requirement is type 1 felt meeting astm d 226 standards.
Substituting synthetic roof underlayments for housewrap.
Position the successive panels.
The main advantage of house wrap over felt paper is the superior strength and durability of house wrap.