white metal roof vs traditional silver metal

[MadisonMPG]

My neighbor has a silver metal roof. Damn thing is like the sun shining in my front door at 12 noon.

[fidalgoman]

All else being equal white will be much cooler than silver. Low-e coatings can be incorporated into coatings design. Like somebody pointed out earlier, roofing companies list the solar index of their products. If it's not listed they might just be embarrassed by it.

[ShadeTreeMech]

Originally Posted by cfg83

joesgot4 -

I vote white with an elastomeric paint/coating.

CarloSW2

This guy knows EXACTLY what he's talking about. I put elasomeric paint on my mobile home roof and the roof went from scorching hot on a mild summer day to ice cold on the hottest days. I swear, the stuff is like magic.

[MadisonMPG]

Could you put elastomeric paint on a car?

[cfg83]

MadisonMPG -

I am guessing yes, but I will let the smarter-than-mes chime in. Depending on the brand, I think they also can have "grainy" characteristics (using super teeny ceramic or glass bubbles that help to increase the insulation value), so there *might* (BIG might) be an aero-benefit to doing that.

CarloSW2

[sandcruiser]

hmmmm.... elastomeric coating on roof on car.
interesting idea.

Might make it a bit cooler when you get in.

The local hardware store had a neat display going--- two plywood boxes w/ a glass front and thermometer inside.

each had the same zinc/steel roofing over it. One was painted w/ a white roofing paint, the other was ... zinc colored. The temperature difference inside the two on a sunny day was dozens of degrees. I don't recall exact numbers, but on an approx 100* degree day (its hot here) in the sun, the plain roofed box was over 150* and the painted one was down by 120-130*. I don't recall how well sealed the boxes were nor if there was breeze that day. That's a pretty big difference. I suspect that the effect is even stronger as you get a larger surface (ie: the little box radiates a lot of heat and is thus closer to ambient temps vs. an entire house roof)

[ShadeTreeMech]

I actually thought about painting a car myself. But it is about $70 for 5 gallons of the stuff.

I bet it would make a car very cool in the summer though!

[Peter7307]

Sort of related to some of the above items...

One other option is an additional roof to form an air space between the new roof and the existing one.
The top roof exposed to the sun heats up and the air flows between that roof and the one below keeping it cooler than it would otherwise be.
This is sometimes called a "fly roof" , tropical roof , false roof etc and was an option fitted to Land Rover vehicles heading to the hot areas. The colour was normally white powder coated aluminium in that case.

Pete.

[cfg83]

Pete -

That would be my ideal house configuration. I always imagine erecting one of those steel and currugated metal versions over my (flat roofed) house. I'm sure the neighbors would have a hissy fit.

CarloSW2

[wagonman76]

I need to redo my roof this summer and have been thinking about colors. I want to go metal. Black would be nice, since Michigan only gets nice and warm maybe 1 week out of the year. The whole rest of the year I need to capture as much heat as possible.

When the sun does shine, it's not going to get hot enough to catch the underlying wood on fire?