Galvalume Cool Roof

They have medium relfectivity and poor emissivity 15.

Galvalume cool roof. It is a trademarked name but many people use it as a generic term to describe a metal roofing product consisting of steel coil coated with a metal alloy. Galvalume was invented by bethlehem steel in 1972. Galvanized and galvalume metal roofs are hot roofs. Normally galvalume is offered in both bare and pre coated pre painted versions.

Galvalume steel is best for use in prefabricated metal wall panels and standing seam metal roof applications with concealed fasteners. Galvalume metal roof and siding panels are coated with a mixture of zinc and aluminum and siliconized coating to help resist scuffs and fingerprints better than a bare metal product. Such a roof can be reasonably expected to be some 50 to 60 degrees cooler than a dark color asphalt shingles roof. Cool roofs can be made of a highly reflective type of paint a sheet covering or highly reflective tiles or shingles.

Portland or 97217 tel 866 465 2523 email. Cool roof rating council 2435 n. Standard or dark roofs can reach temperatures of 150 f or more in the summer sun. In fact a high end kynar 500 white metal roof is energy star rated and classified as a cool roof by the cool roof rating council.

Painting a bare metal roof with white house paint dramatically improves preformance. A cool roof on residential buildings is defined as one with a 3 year aged solar reflectance of at least 0 20 and an infrared emittance of at least 0 75 or minimum sri of 16 in climate zones 10 through 15 for steep slope applications greater than 2 12 and where the roofing product has a density less than 5 pounds per square foot. The mixture of zinc and aluminum protects the galvalume metal against corrosion and rust helping galvalume typically last much longer than galvanized steel. In general a cool roof is one that has relatively high solar reflectance and high thermal emittance.

The term solar reflectance is a measure of the amount of that solar energy that is immediately reflected from the surface. This material will rapidly corrode if it comes in contact with concrete and mortar. A cool roof under the same conditions could stay more than 50 f cooler and save energy and money by using less air conditioning. The main disadvantage of galvalume steel roofing material is the initial cost of the product which is double the cost of a shingled roof.

During the daylight hours a roof is constantly subjected to solar energy striking its surface. Radiant barriers air spaces and added insullation all helps but nothing improves performance like keeping the heat out of the structure to begin with.