Bliss Projects Blog

Considerations when Insulating with Styrofoam Board

Mar 21, 2014

Styrofoam Board Insulation



If you are thinking about upgrading your wall insulation by installing Styrofoam on the exterior, it can be a bit more complicated than just nailing on Styrofoam. As houses are  a building science one thing to be considered is a term call “Dew Point." It has to do with how much insulation is on the inside of your home (warm side) to what is installed on the outside. Because the inside of the home (warm side) has a vapor barrier across the walls before the drywall is installed it is important to know how much the R-value of the Styrofoam on the outside of the wall is. Basically what could happen if this is done incorrectly condensation could start to form in the cavities of the walls that over time may lead to mold and dry rot.

The first step should be talk to an envelope engineer to find out how much insulation should be installed on the outside of the home or building to mitigate any Dew Point problems down the road. This is not only piece of mind, but benefits are a much warmer and comfortable home.


Also, what type of windows is in the home are they being replaced, as well? As I mentioned your home is a building science and one small fix may lead to other issues, it takes very little time to investigate these issues with a qualified renovator and could save you money and problems down the road.


Need advice, Give me a call 250-640-2848. 

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