Shingle color choice - Contractor Talk - Professional Construction and Remodeling Forum

ArnDavis · 07-30-2007, 10:00 AM

Hi. I am installing a comp shingle roof in the Pacific Northwest. In terms of heat loss and absorption, does it matter whether the shingle is a light or dark color? Part of the roof is exposed to sunlight, but most of it is shaded.
Do light shingles tend to discolor?

Thanks,
Arn D.

Grumpy · 07-30-2007, 01:57 PM

A manufacturer, I think GAF, did a study witht heir white and black shingles a few years back. These shingles were placed on similiar test buidlings. They find there to be something like a 20-30 degree surface temporature difference but something like a 2 degree attic temprature difference... when properly ventilated.

I tell my customers to choose a color that looks good because if they are having heat issues they have more to worry about than shingle color. Ventilation is the key to attic temprature, not shingle color.

Very very light colored shingles, such as white, will discolor and show their age sooner than the black shingles.

**Ed the Roofer** · 07-30-2007, 06:42 PM

Just some additional food for thought from the FSEC. This is just one paragraph out of a 67 page report. I disagree with the final findings of this labratory approach method of determining heat gain or loss dependant upon shingle color alone.

Ed

From the FSEC:
"Other tests comparing white and black shingles have shown that shingle color makes a greater difference in peak shingle temperature than the presence or absence of attic ventilation or an attic radiant barrier system.

These tests, accomplished at the FSEC Flexible Roof Facility (FRF), showed
peak temperatures for black shingles (solar absorptance of 97%) to be almost 25°F hotter than peak temperatures for white shingles (solar absorptance of 76%).

Thus, if elevated temperatures can result in composition shingle failure, then the problems are likely to be much more pronounced for darker

shingle products, especially in climates with large quantities of solar radiation."

More from the same source:

"Key conclusions from the above data:

1) A sealed attic results in shingle temperatures that average about 1.3°F hotter over the summer
season. Although this sounds of small consequence, roofing analysts indicate that such increases
have some impact on roof longevity (Cash and Lyon, 2002; Roodvoets, 2001).

2) The difference in shingle temperatures produced by different colors is larger than that produced
by having a sealed attic with an insulated roof deck. For instance, the sealed attic with decking
insulation increased shingle temperatures by a maximum of 8.6°F whereas the increase of black
vs. white shingles was 16.4°F. By way of comparison, note that radiant barrier systems create
increases in peak shingle temperatures of about 5°F (Parker and Sherwin, 1998).

3) While maximum shingle temperature differences were about 9°F, the difference in the roof
decking temperatures under the two roofs was 23°F (166° vs. 143°F) – a large difference. This
indicates a much greater temperature amplitude for the decking to which the shingles are applied

than for the shingles themselves."

theroofinggod · 07-30-2007, 11:41 PM

gaf/elk makes cool roof shingles

Grumpy · 07-31-2007, 08:52 AM

Yes, but those are meant to achieve a certainly "intalled reflectivity" to meet various building codes. So basically all they have is shiny granuals instead of the dull clored granuals common to most shingles.

Ed I may have misread, or lost the flow in all that mumbo jumbo. Did they anywhere state the difference in attic temprature on white to black? It looks like that agreed with GAF's findings of a 20-30 degree surface temprature.

**Ed the Roofer** · 07-31-2007, 10:42 AM

Grumpy,

I will post the link to the entire FSEC report and you can read throught the entire document at your liesure.

It does reference roof surface and attic interior heat during several different test results.

Ed

Grumpy · 07-31-2007, 11:12 AM

That'd be an interesting read for the toilet.

No seriously I have a stack of those types of things I like to read. Knowledge is power and if it helps me even once it's worth the read.

**Ed the Roofer** · 07-31-2007, 04:39 PM

Here you go Tom,

http://www.dca.state.fl.us/FBC/publi...eportFinal.pdf

It sheds some light on some of the more controversial aspects of ventilation requirements.

Here is another version of that report, but in only 40 pages instead of 67 pages.

http://www.fsec.ucf.edu/en/publicati...CR-1220-00.pdf

Ed

2ndGen · 07-31-2007, 04:54 PM

For the homeowner who's actually going to stay in the house for the next 20+ years, I tell them to get whatever they want. It should make them happy.

Now as for brighter vs darker? I believe that the only real difference in temperatures is in the actual material itself.

Now as for wear and tear? Solid colors will show aging, wear and tear alot faster than say a blended color.

When asked by my customers what I suggest, I tell them to choose siding friendly colors (brick, vynil, wood, etc...). I show them examples of colors and styles that are considered appropriate for their particular home style (e.g. tudor, mediterranean, Victorian, colonial, etc...). I usually suggest a dark brown or slate blend and stay away from solid whites or blacks (if they even exist).

If their going to sell the house (whether quickly or later on in a few years), I tell them to get a nuetral color so that it won't be a hinderance when selling the house on down the line.

But ultimately, a blended color in a natural earthtone is a pretty safe bet.

theroofinggod · 07-31-2007, 10:08 PM

in my experience the dark colored roofs will need replacement before the white due to heat absorption