Galvalume vs Painted Metal Steel Roof

Hello,

I have been told a couple different things about what roof to use. The guy at Mueller told me Galvalume will make the building hotter and it will actually change color over time.

The other builder we spoke to said it wont change color and it keeps the building cooler by reflecting heat vs a white metal roof.

From those who have used both or have any information on which one will keep the building cooler please post your thoughts.

Any advice from others is welcomed.

Thanks

I have galvalume and its definitely cooler in the summer-its not as shiny as when new but no color change-only about 16 months of weather so far though.

When I did my steel building in year 2000 I initially told the company I wanted white as I figured it would be cooler. They said it might be somewhat cooler but the white finish would not hold up as well. I have been on my roof a couple of times in the past two years repairing leaks (screws that missed the purlins) and yes, the finish has darkened some, possibly from holding dirt (its not as smooth as a color finish) but after 12+ years in the Georgia weather, it has held up quite well.

donaldusmc2003 said:

Hello,

I have been told a couple different things about what roof to use. The guy at Mueller told me Galvalume will make the building hotter and it will actually change color over time.

The other builder we spoke to said it wont change color and it keeps the building cooler by reflecting heat vs a white metal roof.

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This is something akin to a Ford vs Chevy argument. I do think the Galvalume will last longer than the baked on paint finish. (we're talking say 50 years here, vs 30 or 35 for the paint).

Charles

I have 3 bldgs w steel roofs. One is 25+ years. The other 2 are 5 - 10 years old. They're located in northern NY so snow and ice beats on them every winter. I wouldn't have anything else up there. I usually have a few screws work loose every year. But no problems to speak of.

Not familiar with the other product you mentioned.

Forest Road said:

Not familiar with the other product you mentioned.

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They are both metal roofs. One is baked on paint, the other is galvanized with aluminum (similar to aluminized exhaust pipes).

The heat reflectivity of aluminum coated vs white painted can be debated. Frankly, the rough surface of the aluminized coating should be LESS reflective, hence it should absorb more heat. How the coatings age over time is an issue that can only be answered with test data. My guess is that the thermal difference between the two isn't worth arguing about, and anyone who says one is better than the other is basing this on personal prejudice with absolutely no test data to back it up.

I have painted on my shop and garage and galvanized on the barns. I can't say that I can tell the difference, but the painted seems to be holding up much better over time.

I put galvalume roofing on our home in 1995. This is at 8500 ft. elevation with large temperature swings, snow and ice, intense UV, etc., and I was told by the supplier that the "look" of the steel would gently "age" over the years but would still look nice. I mean, if I did not go with the painted galvalume option.

I went with bare galvalume. It's been some 19 years and I can't tell any difference. Possibly, were I have a piece of brand-new metal to compare, I'd see a change. But if there is any, I don't see it.

This is not the same product as straight galvanized steel. [Think that inexpensive "barn roofing."] I have used that, too, on an old shed. It has weathered some over about the same time period, but no rust or anything, just a "darker" or slightly oxidized look to the surface.

I am happy with the galvalume and would use it again in an instant. I cannot attest to the difference in heat reduction compared with painted steel, as I don't have any. My house seems to be a bit cooler on hot days than it was back when we had cedar shingles for roofing. But I never measured for that, so I cannot say with certainty. I doubt the difference is anything to write home about. But, I didn't install the galvalume to cool the house, I wanted something I'd never, ever have to replace and never have to re-roof our house.

joe_padavano said:

They are both metal roofs. One is baked on paint, the other is galvanized with aluminum (similar to aluminized exhaust pipes).

The heat reflectivity of aluminum coated vs white painted can be debated. Frankly, the rough surface of the aluminized coating should be LESS reflective, hence it should absorb more heat. How the coatings age over time is an issue that can only be answered with test data. My guess is that the thermal difference between the two isn't worth arguing about, and anyone who says one is better than the other is basing this on personal prejudice with absolutely no test data to back it up.

I have painted on my shop and garage and galvanized on the barns. I can't say that I can tell the difference, but the painted seems to be holding up much better over time.

Click to expand...

Same here, I have both and cant tell the difference as far as heat goes.