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Why Roofs can't be made reflective?

08/27/2007 3:43 PM

What would be problems with having a roof coating made of reflective materials to reduce heat energy into attic space? also, why is the reflective side of roofing deck board faced down toward the attic?

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#1

Re: Why Roofs can't be made reflective?

08/27/2007 3:45 PM

It would dazzle airline pilots.

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#2

Re: Why Roofs can't be made reflective?

08/27/2007 4:28 PM

Or just white!

I live in Texas with a BRUTAL sun!

I painted my hangar ultra pure white. It used to be blue.

The walls went from being untouchable to cool.

I have seen white shingles on houses which I am sure helps keeps the houses cooler during the summer but maybe not so much a help in the winter.

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#3
In reply to #2

Re: Why Roofs can't be made reflective?

08/27/2007 6:35 PM

Here in Southern Spain, everything is white, the roofs, the walls, everything! If you spray water on the walls just after the sun has set, the house cools even quicker! I made the mistake of buying a car with a black interior, I've lost skin on the wheel a few times due to the heat!

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#4

Re: Why Roofs can't be made reflective?

08/27/2007 10:54 PM

The reflective side serves two purposes, one is as a moisture barrier and the other is to reflect the heat back into the home during cool periods

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#5

Re: Why Roofs can't be made reflective?

08/27/2007 11:44 PM

Making roofs white sounds like a good idea. And why not also avoid the common practice (in the U.S.) of painting parking lots with black asphalt? Of course we can't expect parking lots and roads to retain a nice white color, but they could be gray instead of black. By taking advantage of every opportunity to make artificial surfaces more reflective, maybe we can help keep the Earth's surface a bit cooler. Now some of you must be wondering if I'm kidding. Well, yes, sort of. But also curious if it would actually be worthwhile, even if it just affects the local environment. After all, the heat-island effect is well established for large cities.

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#8
In reply to #5

Re: Why Roofs can't be made reflective?

08/28/2007 7:54 AM

What if white asphalt is used for the streets and used black stripes instead of white stripes? We probably won't need street lights and save a lot of electricity.

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#14
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Re: Why Roofs can't be made reflective?

08/28/2007 10:05 AM

Just how long do you expect the street to stay white with Black rubber tyres and oil drips??? one day, one week?

Grey would appear to me to be a better option, or cement color....though i do know that cement roads have some other problems as well of expansion etc etc....

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#18
In reply to #14

Re: Why Roofs can't be made reflective?

08/28/2007 2:35 PM

White is great for the daytime. I drive a long country road at night and it is cement colored. It is very reflective and when oncoming traffic is present the headlight glare off of the reflective surface is blinding at times. Even if the oncoming traffic has dims on it appears as brights. Gray would be better.

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#20
In reply to #18

Re: Why Roofs can't be made reflective?

08/29/2007 3:21 AM

Good point that none of us thought of.....

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#6

Re: Why Roofs can't be made reflective?

08/28/2007 12:07 AM

I noticed quite a difference when I reroofed and used "white" shingles instead of the black that were on the house when I bought it. Can't remember what the difference was but with a IR thermometer it was easy to see. Thus, people in hot countries wearing white.

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#7

Re: Why Roofs can't be made reflective?

08/28/2007 6:48 AM

Great idea. How about taking it one step further. What if roofs were made of a material that would change color, white in summer and black in winter.

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#9
In reply to #7

Re: Why Roofs can't be made reflective?

08/28/2007 8:39 AM

That only happens in NEVER NEVER LAND and PETER PAN FLIES OVER HEAD!

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#10
In reply to #7

Re: Why Roofs can't be made reflective?

08/28/2007 8:44 AM

There was a case in LA where some new building with a bright polished stainless steel exterior would heat up the neighboring buildings when the sun was at the correct angle.

I suppose the pedestrians on the sidewalk were not to comfortable either....

Roofs might not pose the same problem.

Now if I could just keep the vents open when there's a foot of snow on the roof. Any suggestions?

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#11
In reply to #10

Re: Why Roofs can't be made reflective?

08/28/2007 8:52 AM

Why not look at a cars rear window? Thats a 12v heating matrix stuck on the glass! Could this not be adapted to keep the snow off the vents! (It's just an idea?)

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#12

Re: Why Roofs can't be made reflective?

08/28/2007 8:59 AM

Years ago, I sprayed a roof of a home in S. Carolina with a white Polyurethane foam. The temperature differential on the roof, before and after, was over 50 F. The tiny air and carbon dioxide bubbles in the foam also acted as an insulator, both in summer and winter. So, if we have all these millions of homes and buildings that are absorbing and reflecting all this solar heat, why hasn't someone come up with a way to convert this xs heat into useful energy, much like the circulating water cells on roofs, etc., but more efficient. Do they make reasonable cost solar panel roof shingles?

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#13
In reply to #12

Re: Why Roofs can't be made reflective?

08/28/2007 9:37 AM

oil companies won't allow it.

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#15

Re: Why Roofs can't be made reflective?

08/28/2007 10:37 AM

Thanks a lot ! Now my wife will be on the roof for hours before we go out !

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#16

Re: Why Roofs can't be made reflective?

08/28/2007 10:39 AM

The answer is that they already do. At least in commercial buildings especially in California and Florida. I believe it is called the "cool roofs initiative". The final coating on an insulated roof is either a very reflective white, or there have been darker pigments which have been developed to show color in the visual range but are reflective in the IR range.

The foil side of current insulation is the moisture barrier. It is metalized plastic, the metal is part of the barrier to stop moisture as plastics are somewhat porous. Or sometimes they just use aluminum foil. The main idea is to keep moisture from inside the house from dampening the insulation and reducing "R" value.

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#17

Re: Why Roofs can't be made reflective?

08/28/2007 2:04 PM

The aftermarket mobil home and RV industries have been using white and aluminized roof coating and sealing products for many years. My first encounters with them date back to the 70's and at that time they were already well established. Nothing new under the sun.

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#19

Re: Why Roofs can't be made reflective?

08/28/2007 3:04 PM

I can offer exclusive shares in Uncle Del's White Bitumen Company....

Allow me to sell you a couple?

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#21
In reply to #19

Re: Why Roofs can't be made reflective?

08/29/2007 3:22 AM

RACIST!!!!!!!


(only joking!!!!)

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