There was a prior topic discussing different options for keeping a home with a tin roof cool. Pardon me for not adding on, but it was long and diverse, and I have a specific question.
It was said that painting the roof with a special reflective white paint would cut down on heat absorption. It's getting on time to paint my roof in any case, so I've considered this. The problem is that white would be blinding. The house is in full sun and the roof is in view from most of the property, and it would be physically painful to look at a white shiny roof.
Is there any way to tint the reflective paint light green and still get benefits? I sort of expect that the answer is no, but wanted to ask before I rule this out.
Oh, and I did the birdholes in the eaves, and have two solar gable fans to push the air, but the birdholes made no difference that I can tell. I think the problem is that it hardly gets breezy here, so there's not much push of air into the vents or the birdholes.
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Google: cool roof coatings
I did find this:
http://www.hawaiiansunguard.com/ They have a white base that they say can be tinted.
Assume the best and ask questions.
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We went from a blue to a white on our roof. I hate it. It is always getting dirty and attracts the sap from the trees, never had a problem with the blue doing this.
I think the lighter the color the better for the heat, but I will never do the white again. We did not use a special reflective paint for the white, the white color itself on the roof has been noticeably cooler in our home. We are re-painting with a green this time around, we may just have to adjust to a little warmer interior again.
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I am going to think that you can get the reflective barrier in a colored painted, as all of the new HPM roofs have a reflective barrier...
That said, I have seen white & silver (aluminum) for sale...
I did find this reflective ceramic paint additive, but have not looked into it.... yet...
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White is by far the best reflector of radiant heat. Silver doesn't work very well as the aluminum in it actually absorbs heat and makes the roof hot. I used the ceramic additive years ago and was not impressed. It may have made some minor difference but not enough to really matter. As far as HPM roofs having a reflective barrier, I don't think it's effective. I have looked at the test that purport to show them reflective a large percentage of radiant heat but that has not been my experience. All of their metals except Mauna Kea White get very hot to the touch. This acts just like a metal radiator radiating heat into the building. White roofs don't get hot.
You can tint some paints but every bit of tint you add decreases the reflectivity of the roof. I know for TPO membrane roofs, a white roof reflects about 95% of radiant heat while the tan reflects only 70%.
Have you considered installing a radiant barrier under the roof somehow? If so, it would need to be separated from the metal roofing by at least 3/4". This is the most cost efficient way to cool a house because it keeps the heat from coming in in the first place. You could tint the roof slightly and add the radiant barrier as a compromise.
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Henry Solarflex 287 is an elastomeric latex based roof paint. As such, it should be tintable especially if you are going for a pastel color. You won't be able to match a color exactly but I am sure they would work with you in the Home Depot paint department to get something close to what you like. It is inexpensive too. About $85 for five gallons.
Any paint that is not a roof paint will fade completely and begin to peel in about 3 years. I have observed recently some roofs that were painted just a few years ago and they have all either faded completely or the paint has come off.
Kathy, Just wondering, what color is your roof right now ?
Hotinhawaii, How are these folks prepping the roof for re-paint ? By "fade" do you mean lose color or start to get chalky ?
mahalos,
pog
The colors sound nice to me .... Driving around the wife and I are constantly looking for natural combinations.
Never would have thought the light ? pale green was *that* hot.
My only .02 Kathy is to have someone you trust get up there and really evaulate it. From your statement of wanting to sell it, will the money spent return upon sale or should you go for the color that would make the sale better ? I remember my mom calling to say she put a new roof on just prior to selling her house 'cause her realtor told her to ... The old roof was perfectly fine and now she is paying 15K for what ? Drove me nutz. *I can answer my own question as painting is different than replaceing but still hate to see money spent when its not ness.
aloha,
pog
aloha,
pog
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Anybody know how the white works here with mold, mildew, etc I do know it appears on my white painted exterior wood.
When we bought our house in Atlanta, it really needed a new roof. I found asphalt shingles a "snow something" color - basically white, and the Atlanta sun can be brutal. What I didn't know was our area was susceptible to some sort of algea and within a few
short years the roof looked terrible. When we sold the house we reroofed just because of appearance, the roof itself had years of functional life left, but it sure didn't look it from the street. My last white roof.
David
Ninole Resident
Edited typos
Ninole Resident
David and stuff growing on roof owners .. did bleach not clean it up ?
aloha,
pog
