White Roofs

[MattM]

http://www.nytimes.com/2009/07/30/science/earth/30degrees.html?_r=1&

Anyone use this on their own homes?  I'm tempted to cut my summer electricity bills.  Not so sure the wife will go for me painting the roof a lighter color.

[john8750]

I like it. Also an attic fan works good. I wonder about that wasted heat though.

John Smith

[Harold in CR]

 Don't understand why wife has the say for the color of your roof ? It is definitely necessary to get it white as possible. The sun will be partially deflected and white will not absorb the heat.

 Down here, in the jungle, all the roofs are red or green. The people thought (they know) the Gringo is LOCO. BUT, my house is cooler than theirs. We get acid rain from the nearby volcano, that coats things with a fine black algae/fungus. I have to wash the roof with soapy water, during the dry season.

 Just about finished replacing the tin roof, and, next year, after the oils are washed off the tin, from manufacturing processes, I will definitely apply a white roof coating.

 When living in Florida, we had a brownish color shingled roof. Attic was hot enough, that we put green (freshly sawn) lumber up there to dry it. Hurricanes damaged the shingles, so, we replaced all the roofing with a dirty white color, that was the only thing close to white and, the attic was "tolerable" .

[CraigM]

Do a search for Hydrated Lime, aka Whitewash. There are a few articles about whitewashing existing roofs on www.builditsolar.com/Projects. Very inexpensive option.

Craig

[birdhouse]

i work on ~300,000 sq ft of commercial buildings.  probably 90% of them have been treated with a white elastomeric coating.  they are all flat roofs, but much applies to shingled gable roofs as well. 

there are many advantages besides the cooling in summer.  1-  the roof expands and contracts far less due to less thermal variance.  2-the stuff with make an existing roof last much longer because the coating gets all the UV and helps the underlayer last longer.  3- elastomeric can seal up leaks in a situation where the only other option is to re-roof. 

high end elastomeric jobs use a fabric that is wetted out (much like fiberglass) with the elastomeric.  then a final top coat is put down.  our coating contractor will give a ten year warranty for leaks on any roof he treats this way. 

i use the fabric/elastomeric all the time to fix leaks.  it is hands down the easiest way (provided temps are high enough for curing) to fix leaks.

adam 

[electrondady1]

i have about two ft. of snow on right now so all my roofs are white.

 i painted my low slope roof white with some special roof paint 3 years ago
it's cooler in the summer .
 thinking of ways of storing summer heat.

[wewantutopia]

Last spring I installed bright white standing seam hidden fastener steel roofing on a section of my roof that has a 2/12 pitch.  (I only did that section for aesthetic reasons and it is over my 1 year old son's room).  The area is about 160 sq. feet. 

It made a noticeable difference last summer!

[MattM]

Standing seams are cooled two fold.  First they should - using the clips - sit off the decking thereby allowing airflow underneath the panels.  And secondly they block infrared wavelengths.  The exception to the rule is copper which picks up environmental heat rather well.

[ToddT58]

Years ago, a friend had matching mobile homes he rented out. He painted one roof silver and the other one white. Turned off the AC and put a thermometer in the same corner. The home with the white roof was 32 degrees F cooler! I had a flat roof on an office and was looking at having to add more AC capacity as it just couldn't get cool until I remembered my friend's experiment. Before my shop foreman finished painting the white mobile home roof coating on the flat roof, the AC quit running the first time in days. The difference was remarkable.

[MattM]

One day somebody is going to make fancy white canvas roof cover that sits over roof shingles and snaps into the back of the gutter or onto the drip edge.  It would straighten out and shrink to fit with each rainfall.  You would only need it 4-5 months a year and for the average house it would probably run $450-500.  Fold it up and throw it in the garage during the cooler months.  But knocking 30% off your cooling bill would pay for it the first season.  If it gets dirty refresh the look with white paint.

[hiker]

white looks uncool..but my house is a lot cooler now..
had a dark color roof a few years back..time to change roofing paper so i went with white -just becauce it was cheaper...now the house dosent get like a oven in the summer  ;}