Galvalume Cool Roof

The main disadvantage of galvalume steel roofing material is the initial cost of the product which is double the cost of a shingled roof.

Galvalume cool roof.

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. During the daylight hours a roof is constantly subjected to solar energy striking its surface. Such a roof can be reasonably expected to be some 50 to 60 degrees cooler than a dark color asphalt shingles roof. It also takes longer and requires special training to be installed as it can easily dent.

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. Painting a bare metal roof with white house paint dramatically improves preformance. Radiant barriers air spaces and added insullation all helps but nothing improves performance like keeping the heat out of the structure to begin with. Galvanized and galvalume metal roofs are hot roofs.

Galvalume was invented by bethlehem steel in 1972. The mixture of zinc and aluminum protects the galvalume metal against corrosion and rust helping galvalume typically last much longer than galvanized steel. A cool roof under the same conditions could stay more than 50 f cooler and save energy and money by using less air conditioning. This material will rapidly corrode if it comes in contact with concrete and mortar.

Standard or dark roofs can reach temperatures of 150 f or more in the summer sun. They have medium relfectivity and poor emissivity 15. Normally galvalume is offered in both bare and pre coated pre painted versions. Cool roofs can be made of a highly reflective type of paint a sheet covering or highly reflective tiles or shingles.

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. Cool roof rating council 2435 n. Galvalume steel is best for use in prefabricated metal wall panels and standing seam metal roof applications with concealed fasteners. 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. We would not recommend using galvalume panels with exposed fastener steel roofing systems such as corrugated or ribbed steel roofs.