Galvalume Cool Roof

Galvalume was invented by bethlehem steel in 1972.

Galvalume cool roof.

Cool roofs can be made of a highly reflective type of paint a sheet covering or highly reflective tiles or shingles. Galvanized and galvalume metal roofs are hot roofs. Normally galvalume is offered in both bare and pre coated pre painted versions. It also takes longer and requires special training to be installed as it can easily dent.

Lighter color roofs reflect sun s heat much better than darker colors. This material will rapidly corrode if it comes in contact with concrete and mortar. We would not recommend using galvalume panels with exposed fastener steel roofing systems such as corrugated or ribbed steel roofs. During the daylight hours a roof is constantly subjected to solar energy striking its surface.

The term solar reflectance is a measure of the amount of that solar energy that is immediately reflected from the surface. 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. Such a roof can be reasonably expected to be some 50 to 60 degrees cooler than a dark color asphalt shingles roof. Standard or dark roofs can reach temperatures of 150 f or more in the summer sun.

Cool roof rating council 2435 n. Radiant barriers air spaces and added insullation all helps but nothing improves performance like keeping the heat out of the structure to begin with. The main disadvantage of galvalume steel roofing material is the initial cost of the product which is double the cost of a shingled roof. 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 mixture of zinc and aluminum protects the galvalume metal against corrosion and rust helping galvalume typically last much longer than galvanized steel. Galvalume steel is best for use in prefabricated metal wall panels and standing seam metal roof applications with concealed fasteners. Painting a bare metal roof with white house paint dramatically improves preformance. 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.

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. They have medium relfectivity and poor emissivity 15.