Forums » Off-topic discussion » Has anyone actually painted their roof white? 1 2 3

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  July 19, 2011 8:43 a.m. z31maniac SuperDork

  As the title states, the wife and I are trying to do everything we can to our small house (1150sq ft) in OK, to make it as energy efficient as possible. The home was built in 1974 for reference.

  The house has a relatively new AC condenser, but still the old blower inside, but this will be the last to be tackled.

  Of course, we have switched all lights in the house over to CFLs, which has made a difference. And recently had some insulation blown-in the attic, since there was none before. I believe we blew in the equivalent of R-40 in the attic.

  That has already made a difference with how much the AC is running during the night/morning, and now by the early evening, the house will have gained less temp than before. The house used to heat up to 76-78 by 6pm in 100+ temps, now it's only heating up to 72-73 during 100+ temps.

  We also had Thermal Windows come give us a quote yesterday, but not sure we are ready to drop the $5200 on new windows and sliding glass door.

  Sorry for the long winded post, so has anyone painted their roof white? What products to use? Thoughts/opinions?

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  July 19, 2011 8:49 a.m. bravenrace SuperDork

  No, I haven't. But I have looked into various ways of saving energy in our 62 year old house. One thing I've found is that it is easy to pass the point of diminishing returns. You need to carefully estimate the value of something like the windows you mentioned, and calculate your break even point to determine if the upgrade is reasonable or not. I've never heard of painting your roof white, although I understand the intent. Do you have an asphalt shingle roof? Having no experience with this, my concern would be how you would do it to completely cover the existing color and make it last without peeling. It also seems like it would look like Hell, but that's your call.

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  July 19, 2011 8:57 a.m. z31maniac SuperDork

  Yeah, it would look crappy, no doubt. I'd likely only do the back slope of the house. Our house faces north, so doesn't see nearly the direct sun that the back of the house sees.

  I'd also need to check and see if their is any code against it (no HOA, but I can see people complaining).

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  July 19, 2011 9:00 a.m. davidjs Reader

  I'm not sure I've ever seen a study on it for asphalt shingle roofs. Most of the stuff I've seen is for flat tar roofs, which usually won't have the benefit of an attic.

  Maybe sealing off the ceiling and then a solar attic fan would get the same gains for a whole lot less WTF factor?

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  July 19, 2011 9:02 a.m. Giant Purple Snorklewacker SuperDork

  No, but I did get a HUGE boost from putting a temp activated fan in the attic to keep the heat build-up closer to the outside temps. It draws air in the eves and vents it through the roof. IRC it comes on at 90F.

  Lord of drivel and harbinger of Floundering

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  July 19, 2011 9:02 a.m. bravenrace SuperDork

  It wouldn't be an immediate solution, but the PO of our house planted a lot of trees in strategically placed areas that leave our house almost always in the shade. It also has huge overhangs which also helps. We don't have A/C and don't need it, as our house is uncomfortable maybe a total of a week a year. My shop IS air conditioned, so when it's really bad we just go sleep out there!

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  July 19, 2011 9:04 a.m. bravenrace SuperDork

  In reply to Giant Purple Snorklewacker:

  But how much energy does it use? Maybe not much, but it's these kinds of things that need to be carefully evaluated if the goal is to save energy.

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  July 19, 2011 9:08 a.m. foxtrapper SuperDork

  Until just a few weeks ago, I was an enthusiastic supporter of painting the roof white for summer, and black for winter. I've baked enough under them, and frozen in the winters. God this should work well!

  But then the black solid rubber roof was installed. With an inch thick layer of foamy underlament stuff.

  Oh my.

  What was a stinking hot attic in the summer suddenly has become cool. So cool it's possibly the coolest room in the house. It rivals the basement. it is substantially cooler than the next two levels down.

  This attic already had fiberglass insulation in the ceiling.
  

  What I'd thought was good enough insulation, clearly wasn't. You might do quite well with even more attic insulation.

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  July 19, 2011 9:11 a.m. z31maniac SuperDork

  bravenrace wrote: In reply to Giant Purple Snorklewacker: But how much energy does it use? Maybe not much, but it's these kinds of things that need to be carefully evaluated if the goal is to save energy.

  I'm going to assume he meant a solar powered one....

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  July 19, 2011 9:27 a.m. Raze Dork

  Ridge vents + powered attic fan (either solar or wired in) are your best friend. Also, go get some great stuff expanding foam and seal all windows, doors, wall / floor joints, if you have a basement get some stripping along the bottom of the door to seal it. Likewise if you have an attic door get an attic tent to seal any leakage there.

  I've been battling the same thing, only I have the equivalent of R10 in my attic right now (waaaaay too little, going to blow in a bunch this winter), and my attic fan was toast when my wife and I moved in last year in July. I couldn't keep the house cooler than 18 degrees below ambient outside, which on 100deg days meant upstairs was 82 deg. I replaced the attic fan and had my ridge vents extended when I had a new roof put on. I also sealed every crack and crevice with expanding foam or silicone. Now I'm at 24 deg below outside ambient. After I get an attic door tent and some R30-40 in the attic I'm hoping I'll be pushing 30 deg below ambient (that's my goal). As a reference to how much an attic fan does, without it working last summer on 100 deg days even with ridge vents, I took a thermometer up there and it was 130+ deg. The lack of insulation meant my ceilings would reach 87 deg (highest measured) and essentially bake the inside of my house like an oven. I went up there this summer with a thermometer again, I set the fan to come on at 95 deg, and it was 100 deg in the attic. Ceiling temps were at 74 deg (highest recorded based on hottest day thus far, inside was 74 deg, outside ambient was 97 deg.

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  July 19, 2011 9:28 a.m. Raze Dork

  bravenrace wrote: In reply to Giant Purple Snorklewacker: But how much energy does it use? Maybe not much, but it's these kinds of things that need to be carefully evaluated if the goal is to save energy.

  The cost of running a small electric fan on a temp switch is much less than running your A/C unit full bore hours into the night to make up for the lack of cooling all day that the fan provides....

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  July 19, 2011 9:43 a.m. keethrax HalfDork

  Raze wrote:

  bravenrace wrote: In reply to Giant Purple Snorklewacker: But how much energy does it use? Maybe not much, but it's these kinds of things that need to be carefully evaluated if the goal is to save energy.

  The cost of running a small electric fan on a temp switch is much less than running your A/C unit full bore hours into the night to make up for the lack of cooling all day that the fan provides....

  Ideally you'd want it to be based on not just the temp in the attic, but factor in the outside temp as well. No point in evacuating an attic full of 100 degree air if it's 100 degrees outside. But even without that, they're often huge savers.

  In fact, now that it occurs to me, I may rig something up to do just that when I install the fan that's currently sitting in a box waiting to be installed. Something like run fan if temp in attic > X and difference between attic and outside temp > Y. Time to scrounge the electronic parts bins upstairs.

  '08 Mazdaspeed3, '00 PontiacGrand Prix GT, '99 Metro, '96 Cherokee

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  July 19, 2011 9:43 a.m. Giant Purple Snorklewacker SuperDork

  bravenrace wrote: In reply to Giant Purple Snorklewacker: But how much energy does it use? Maybe not much, but it's these kinds of things that need to be carefully evaluated if the goal is to save energy.

  It is a 120v 3a electric motor that moves a lot of air quickly and shuts off. Considering that it only runs 4-5 months out of the year and only at 5 min intervals during the peak of the day... not too much really. The purchase price was $170. The solar units are $250 and I would have done that if I had known they existed at the time.

  Here is the nut of it - the fan does not eat much electricity and my AC does. It used to run 8hrs a day constantly and now it cycles in 30min on 30 min off. My electric bill is down $40 from last June. Obviously I can't compare directly because weather isn't consistent but over the whole season I expect the savings to continue thru July/Aug and to break even or be ahead in a year not counting less wear on the AC components "might" mean longer life.

  Lord of drivel and harbinger of Floundering

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  July 19, 2011 9:46 a.m. 81cpcamaro New Reader

  bravenrace wrote: It wouldn't be an immediate solution, but the PO of our house planted a lot of trees in strategically placed areas that leave our house almost always in the shade. It also has huge overhangs which also helps. We don't have A/C and don't need it, as our house is uncomfortable maybe a total of a week a year. My shop IS air conditioned, so when it's really bad we just go sleep out there!

  Trees do help quite a bit. My house was built in the middle of a lot of trees, around 500+ trees on 2.2 acres. My power bill (all electric) was $65 last month, that's with 95 temps and Georgia Humidity. Trees that drop their leafs are best, that way you get benefits of the sun in winter to help with heating.

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  July 19, 2011 9:46 a.m. DILYSI Dave SuperDork

  I've wondered about a different kind of roof. first, you have a traditional roof. Asphalt shingles or whatever. Then, a 2-4" air gap, then a metal roof. The thought is that air gap would a) insulate and b) allow the hot air under the metal to rise to the ridge vent.

  I've seen a similar idea installed in attics, but this would actually be on the exterior.

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  July 19, 2011 9:56 a.m. z31maniac SuperDork

  In reply to everyone: Looking into attic fans now, not sure why I wasn't thinking about that before.

  In regard to trees: Not a legitimate possibility, because I doubt we will be here past 5 years, and out big backyard is big because of the high tension power lines that run through ours and the neighbors. Still probably enough room, but just seems like as they grow it would cause another headache.

  In reply to DILYSI Dave: I've wondered the same thing. Anything to shade the roof from the direct sunlight would certainly have a marked effect.

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  July 19, 2011 9:56 a.m. 914Driver SuperDork

  How are the walls, insulated as well as the attic? If not there's a good return on investment.

  Dan

  BMW -- You don't need a hibachi to cook rice.

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  July 19, 2011 10:08 a.m. z31maniac SuperDork

  Walls are insulated.

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  July 19, 2011 10:36 a.m. Keith SuperDork

  DILYSI Dave wrote: I've wondered about a different kind of roof. first, you have a traditional roof. Asphalt shingles or whatever. Then, a 2-4" air gap, then a metal roof. The thought is that air gap would a) insulate and b) allow the hot air under the metal to rise to the ridge vent. I've seen a similar idea installed in attics, but this would actually be on the exterior.

  On an old Land Rover, it's called a "safari roof"

  I'd blow more into the attic myself. Excellent bang for the buck. I might look into the attic fans myself, we have some wicked solar gain around here.

  Square left in 50 caution ocean!

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  July 19, 2011 10:56 a.m. Salanis SuperDork

  81cpcamaro wrote: Trees do help quite a bit. My house was built in the middle of a lot of trees, around 500+ trees on 2.2 acres. My power bill (all electric) was $65 last month, that's with 95 temps and Georgia Humidity. Trees that drop their leafs are best, that way you get benefits of the sun in winter to help with heating.

  I've got a friend looking into planting hops to run up the side of his house and onto a portion of the roof. Relatively cheap, will reach full height (20'-30') after a year, retreat back to the rhizome for the winter, and are stupid easy to grow.

  The added benefit of having fresh hops for brewing does not hurt at all either.

  Follow my journeys in beer and brewing: http://brewercameron.wordpress.com

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  July 19, 2011 11:09 a.m. keethrax HalfDork

  z31maniac wrote: In regard to trees: Not a legitimate possibility, because I doubt we will be here past 5 years, and out big backyard is big because of the high tension power lines that run through ours and the neighbors. Still probably enough room, but just seems like as they grow it would cause another headache.

  There are some fairly tall, fast growing, small footprint trees. But if you're talking 5 years, I probably wouldn't bother either.

  '08 Mazdaspeed3, '00 PontiacGrand Prix GT, '99 Metro, '96 Cherokee

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  July 19, 2011 11:18 a.m. Strizzo SuperDork

  Salanis wrote:

  81cpcamaro wrote: Trees do help quite a bit. My house was built in the middle of a lot of trees, around 500+ trees on 2.2 acres. My power bill (all electric) was $65 last month, that's with 95 temps and Georgia Humidity. Trees that drop their leafs are best, that way you get benefits of the sun in winter to help with heating.

  I've got a friend looking into planting hops to run up the side of his house and onto a portion of the roof. Relatively cheap, will reach full height (20'-30') after a year, retreat back to the rhizome for the winter, and are stupid easy to grow.

  The added benefit of having fresh hops for brewing does not hurt at all either.

  vines up against/on the house will hold moisture against the siding/brick and foundation, causing bigger problems than high electric bills though.

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  July 19, 2011 11:29 a.m. Salanis SuperDork

  You don't have them climb up the walls. You put a post or guide string up a couple feet out, and it climbs up that.

  Follow my journeys in beer and brewing: http://brewercameron.wordpress.com

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  July 19, 2011 12:00 p.m. 914Driver SuperDork

  More in the attic, perpendicular to the joices. Make sure the gable and sophit vents are clear.

  BMW -- You don't need a hibachi to cook rice.

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  July 19, 2011 12:02 p.m. ultraclyde HalfDork

  foxtrapper wrote: But then the black solid rubber roof was installed. With an inch thick layer of foamy underlament stuff.

  Rubber roof, you say? Details? Linkature?

  "It's hard to be a visionary in a world full of blind people." - JM

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