Robert Smits
What is the relative reflectivity between Galvalume and a metal roof coated with a reflective substance or color? Do you have a web site where I can research this? We are getting ready to re roof a 36 yr old home with 12 yr old asphalt shingles and also building a Metal storage building/workshop. Thanks, Bob
David Stermer
Robert, Thanks for the question. Galvalume has a relatively high solar reflectance, in the neighborhood of 50%. Typically only whites and light colors have that high of reflectance. ENERGY STAR lists values for many roof products at this web site.Select the last item - Qualified Roof Products. Regards, David Stermer
Guest User
We're getting a metal roof. We know that we want plain old white for the color to reflect as much of the light and heat as possible. Other than the paint color what else should we be looking for in a product or coating that will help reflect as much heat and light as possible?
Todd Miller
Classic Products, Inc.
White will be most reflective. However, especially if you live around a lot of trees, white will not stay white for long. If tree sap lands on it, that sap will hold dirt and can even support biological growth. With today's reflective pigments which help to make even dark colors meet Energy Star standards, I feel that folks do not have to have a white roof if they do not want one. Also, for enhanced energy efficiency, re-roofing is the time to take a look at ventilation and insulation as well.
An informed customer is our best customer.
I wouldn't, personally, own a white car or roof. Shows dirt to readily like Todd said. The reflectivity performance is built into the paint as well as the colors. Get the color you want and I am sure they have high reflectivity options. Where is the home located, how is the attic vented, etc, etc.
Nate Libbey
One important factor - While Galvalume is much more reflective than painted, it doesn't release heat very quickly. So while a white or offwhite painted metal roof isn't as reflective, it will release heat much faster than a more reflective Galvalume roof. This is why light colored painted roofs have a better TSR (total solar reflectivity) rating than Galvalume. In my opinion, a light colored metal roof will always outperform a Galvalume roof in energy savings unless you live in an extremely cold area like some parts of Canada.
An informed customer is our best customer.
Good information Nate. We might disagree on the performance aspect of things regarding the roof and how much of a performance impact it should have but that is good information on the Galvalume vs. Painted TSR ratings.
Scott Norris

I am about to replace my Decra roof. It currently has a lighter grey color and my wife and I both like the black shingle color but living in DFW, Texas, we are concerned it will increase the heat in our attic during the sunlight hours. I can't seem to locate the answer on the impact of color choice for the stone coated metal roof. Being a larger 2 story home, my roof stays in direct sunlight most of the day.
We have been told there is minimal impact and I understand that ventilation also plays a large role, but when comparing the same ventilation structure, does the darker colors increase heat within the attic and if so, is there a an estimate of what the impact difference may be?

Todd Miller
Classic Products, Inc.

I would suggest checking with Decra but chances are the current roof has solar reflectivity in the 20% range and the new roof will be more around 5%. Just my guess based on some assumptions. You will steel benefit from whatever attic ventilation you have (perhaps see if it can be increased) as well as by the thermal break created by the airspace between the metal shingles and your roof deck. I really would not expect a huge drop in energy efficiency. There will be some drop but I have no way to quantify it. I am sorry.

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