Metal Roof Vapor Barrier

Metal roofs and buildings require specific insulation and vapor barrier to meet the demands of condensation and breath ability.

Metal roof vapor barrier.

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. In this example although roofs and walls both need similar water vapor barrier properties the roof barrier often needs to be either inflexible or air permeable to prevent being blown away in an updraft. We ll add a vapor barrier so the moist air does not flow up through the insulation and condense on the roof. In metal buildings there are a few possible consequences of trapped moisture in wall and roof systems.

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. Long term in service roof performance can be affected by several important factors including. What is a roof vapor barrier. 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.

This is by far the most common way to install a metal roof. Most buildings especially those with metal roofing or siding can benefit from a roof vapor barrier. Corrosion of metal components even on surface treated metal. When exposed to moisture metal components can oxidize and weaken decreasing the life of your customer s building.

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. The problem with using. Underlayment products for use beneath standing seam metal roof systems should be carefully selected. Traditionally we ve insulated the roof panel to try and keep the temperature on the panel from reaching the dew point.

This reflection of the heat eliminates the temperature difference that causes the metal to sweat and drip. Water barrier thermal insulation barrier vapor retarder and air barrier are provided and are in the correct location for a given climate. But a preinstalled membrane may be even more effective at removing condensation. As long as the plywood under the shingle roof is in good condition this way can provide many benefits.

Single bubble vapor barrier acts as a reflector. Vinyl reinforced fiberglass insulation not only provides r value to your metal building but also acts as a vapor barrier against condensation.