Hornung's Helpful Hardware Man

 

Painting a Metal Roof

Q:  I have a house with a metal roof and three years ago I cleaned the roof and used oil base primer then painted it with oil base paint. Now it is flaking so what should I do and wire brush prime and then paint and what kind of paint and primer should I use?

Thanks Dale

A:  In researching this it turns out that there are some oil base paints that are made for roofs. I don't stock them though. Using just a standard oil base paint will probably peal as a result of expansion and contraction. Oil base paints do not have much ability to expand or contract with the steel especially an area in direct sun light and consequently will peal. They will also peal as a result of the metal becoming thin from rusting and allowing moisture to pass through it. When the sun hits that area and there is any moisture on the other side say from a leak close by, the sun will draw the moisture causing the paint to peel. You will be able to tell when you are scraping the roof if it is very thin there and consequently may need to be patched. Also there are some really good products for steel roofs but only come in white like "stay kool", kool seal and other elastomeric roof coatings. Probably a paint store like Duron or Sherwin Williams will stock such paint.
 

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