Putting Up A Moisture Barrier Metal Roof

We ll add a vapor barrier so the moist air does not flow up through the insulation and condense on the roof.

Putting up a moisture barrier metal roof.

Make sure the product is designed to be used under metal. In order to add moisture barrier under metal roof you can spray the undersides of the roof by using a thick layer of polyurethane spray foam. This type of underlayment is critical to a quality roof installation. Traditionally condensation is managed by insulating the metal roof so that the panel temperature never reaches the dew point.

It serves as a moisture barrier as well as a slip sheet. I plan on putting down 1 x 4 strapping on top of the shingles screwed to the joists and then screw the metal panels to the strapping. Once again this is used on cold roof construction. This is often accomplished using vinyl backed fiberglass insulation to prevent humid air from coming into contact with the cooler metal roof which may be at or below the dew point.

Traditionally we ve insulated the roof panel to try and keep the temperature on the panel from reaching the dew point. But a preinstalled membrane may be even more effective at removing condensation. It will help you to eliminate problems that may come when the house becomes extremely cold in the winter and terribly hot in the summer. The problem with this is that as the metal heats up and expands or cools down and contracts it moves a little on the roof.

A roof design that includes an adhered roof membrane with multiple layers of insulation with board joints offset and staggered over a vapor retarder air barrier helps lower the risk that air and the moisture it carries will infiltrate the roof system. Do i really need a moisture barrier underlayment for this project. That reduction of air and moisture infiltration can then help improve roof longevity. The problem with using insulation alone.