Metal Roof Vapor Barrier

A roof vapor barrier needs to have different properties to a barrier in a wall or one used to prevent radon permeating through a floor.

Metal roof vapor barrier.

When exposed to moisture metal components can oxidize and weaken decreasing the life of your customer s building. Metal roofs and buildings require specific insulation and vapor barrier to meet the demands of condensation and breath ability. Underlayment products for use beneath standing seam metal roof systems should be carefully selected. With a little over a month of winter left moisture damage from rain snow and ice remains a concern.

In metal buildings there are a few possible consequences of trapped moisture in wall and roof systems. Single bubble vapor barrier acts as a reflector. Water barrier thermal insulation barrier vapor retarder and air barrier are provided and are in the correct location for a given climate. In the event you are sheeting your roof with plywood or substrate.

We ll add a vapor barrier so the moist air does not flow up through the insulation and condense on the roof. But a preinstalled membrane may be even more effective at removing condensation. 3 install 1 4 purlins down over the shingles before installing the metal roof the third way to install a metal roof over shingles is by applying 1 4 purlins over the shingle 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.

This reflection of the heat eliminates the temperature difference that causes the metal to sweat and drip. As the sun s ray heat the steel the heat radiates through the metal but is reflected back out of the roof by the foil side of the vapor barrier. Most buildings especially those with metal roofing or siding can benefit from a roof vapor barrier. As long as the plywood under the shingle roof is in good condition this way can provide many benefits.

What is a roof vapor barrier. Traditionally we ve insulated the roof panel to try and keep the temperature on the panel from reaching the dew point. Corrosion of metal components even on surface treated metal. Vinyl reinforced fiberglass insulation not only provides r value to your metal building but also acts as a vapor barrier against condensation.

That reduction of air and moisture infiltration can then help improve roof longevity. This is by far the most common way to install a metal roof.