September 3, 2009

Preppy in Pink - Insulation on the Outside

Passersby may be wondering why THE CONCORD GREEN HOME is sporting pink. Actually, its all part of the strategy to super-insulate this house.

We grew up thinking that the old pink fiberglass insulation goes on the inside of the house. Its a whole new world. No spun glass here. Thick and rigid Extruded Polystyrene (XPS) insulation, installed here over Green Guard's Raindrop house wrap, acts as a great thermal barrier, and is supplemented by additional healthy insulation on the inside. This strategy achieves R-values that are significantly higher than required by code (R-value is the measure of resistance to heat flow). The higher the R-value, the better the insulating properties, and the lower the energy consumed to keep temperatures comfy inside.

Next, strapping (long thin strips of wood) is applied over the rigid insulation, which creates an air space between the insulation and the clapboard, also known as a drain screen. This allows moisture to evaporate instead of building up behind the exterior cladding, which can wreak havoc on the health of the structure.


  1. Another great way to achieve R-value is to use a spray foam insulation that maximizes energy efficiency. If you are unfamiliar with the American Green Group, they have a product called "eco-safe foam." This insulation seals all the spaces that traditional fiber-glass and cellulose cannot. Great site by the way, I will be coming back to check up! Feel free to come to my blog any time =D

  2. Hi Lisa, we stopped by to see the site. Very impressive indeed! One of the things I noticed was the plywood used for the sheathing. "No urea or formaldihyde added" was stamped on each one. Are those products usually added to plywood? I know they do add them to particle board.

    I can't wait to see more in the future! I wish you good luck!


  3. Hi Ahmed.

    Glad that you were able to check out our project!

    Yes, any pressed wood product, including plywood, can contain all sorts of chemicals that it is best to avoid.

    Here is a helpful summary from the Environmental Protection Agency:

    Great swapping sustainable build ideas with you. Best of luck in your projects as well.


  4. Hi Anme.

    Your comment is well timed. We are evaluating healthy spray foam insulation options this week, including those that are soy based. Will check your links out.

    Thanks for following along.


  5. Are there respiratory concerns after installation? I was reading about this product on the Owen's website and it was unclear to me. We were hoping to use this to line the ceiling of our crawl space for additional insulation after our radiant barrier for our retrofit radiant floor heating. I have a particular sensitivity to formaldehyde but was trying to make sure there were not other harmful chemicals in this product.


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