White is cool with Obama

May 27th, 2009

Call me a racist, but when we started to build our home 25 years ago, I thought I’d be more comfortable living with whites rather than darks. Now don’t get me wrong, I have nothing personal against darkies. It’s just that I thought, in this part of the country, it would be better to live as a good ol’ whitey. And I’m not ashamed to admit I still feel that way. To my surprise, so does President Obama.

US wants to paint the world white

US Energy Secretary Steven Chu said Tuesday the Obama administration wanted to paint roofs an energy-reflecting white, as he took part in a climate change symposium in London.

Yep, we have a honky roof. Well, actually it’s more like a cracker. Perhaps I should explain.

My Okie roof
We built our house in three sections, two of which have slab like roof construction which result in vaulted style ceilings. The outer surface consists of conventional white fiberglass/asphalt shingles over roofing felt and plywood attached to 2X10 rafters. (These are actual 2X10’s salvaged from an old warehouse.)
Approximately 1.5 inches below that a radiant barrier is attached between the rafters similar to the photo at right. Then comes the fiberglass batts. A layer of 4 mil polyethylene is used as a vapor barrier. The area between the plywood and radiant barrier is vented by soffit and ridge vents. This roof section is about 18 years old.

Another, older, roof section is similarly constructed except that it uses shallow cathedral trusses and the radiant barrier is 1/8 inch thick laminated paper with foil on both sides.

White shingle valuation
First of all, it should be noted that white fiberglass/asphalt shingles are only marginally cooler in direct sun than darker colored shingles. The difference is much less than that of a white and black metal surface such as a car body. Good ventilation is likely a greater cooling factor than the color of the shingles. However, I feel even a 10-15 degree cooler roof slightly helps with not only energy costs, but also roof sheathing degradation. The latter is of special concern due to the heat reflected by the radiant barrier.

No way around it, white shingles are just plain uglier than dark shingles. While few people ever see our house in the woods, this fact could affect resale value for urban and suburban homes. Conversely, white shingles do usually cost less.

All in all, for the vast majority of Okies with composition roofs, we’d probably save more energy, and money, with white roofs on our cars than on our homes. Now, metal roofs are another story:

  • Black acrylic paint: 142deg. F
  • Galvanized steel: 138deg. F
  • Red acrylic paint: 106deg. F
  • Light green acrylic paint: 104deg. F
  • White acrylic paint: 74deg. F
  • Hyper white” acrylic paint : 65deg. F

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