Friday, September 14, 2012

Spray Foam

With all of the electrical and plumbing in place the work this week has been insulation.  Now insulation is something that I've spent a lot of time thinking about.  I know it's not glorious at all and most people think I'm crazy for spending as much time thinking about insulation as I have.  However, Becca and I said from the very beginning of this process that there are certain things we want to make sure we do it right when we build this house and others that aren't quite as crucial.
Things like flooring, colors, fixtures, and even appliances can be easily changed out in the future so we're comfortable saving some money on these things and not getting the best out there.  Insulation, on the other hand, is pretty much set in stone once you get sheet rock up.  For that reason we were willing to spend a little more.  On top of the finality of it all, insulation is a place where you can either save money over the life of the house or regret your decision every month when you see your utility bill.  For all of these reasons I knew that I wanted spray foam insulation throughout the entire house.
Spray foam works so well for a few different reason.  First off, it has a higher R value, or the measure of how well it resists changes in temperature, than your typical fiber glass insulation.  The higher the R value the harder it is for the hot in the summer and cold in the winter to absorb into your house.  The other benefit of spray foam is when it's applied it actually expands into all the nooks and crannies of your walls.  This essentially creates an air tight seal around your entire house.  The benefit of this seal is now you no longer have to worry about the drafts that can result from poorly sealed homes.
Now there are some potential drawbacks to spray foam.  First off is the cost; it's substantially higher to do your home with spray foam vs conventional fiber glass siding.  We knew upfront that spray foam was the way we wanted to go so we had already built it into the budget.  The other thing to consider is that the energy savings you'll see from the higher insulating properties.  There are a lot of variables when trying to calculate how long the spray foam takes to pay off including climate, house size, and utility costs, but most web sites will state anywhere from 3 to 7 year payoff.  So if you plan on being in your house longer than that, the foam will pay itself off and even save you money in the long run.
The other potential drawback to spray foam is that it has the possibility of being too air tight.  I know that might sound counter intuitive, but houses are actually designed to "breathe" a little naturally.  Spray foam tends to be so tight that it prevents this which can result in things like moisture build up and condensation in your house.  The solution to this, introduced to me by our builder Jason, is an Energy Recovery Ventilator (ERV).  This system essentially replaces your houses natural air flow by a mechanical system that will bring fresh air in from the outside and exhaust other air back out.  There are other benefits to an ERV system, but at its basics this is the huge benefit of one in a spray foam system.
As you can see this is something I spent a lot of time thinking about and am actually excited to see if all the work was worth it or not.  Over the last week the insulators have been able to spray foam all of the exterior walls and are now coming back through as sheet rock gets put up to spray places like the ceilings in the attic.  It's a pretty neat site.

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