What’s all the talk about foam insulation?  Does it work and what types are there?

Yes, foam is good for residential and commercial construction practices.  The two main types of spray foam are closed cell and open cell foam.  The closed cell foam is a vapor barrier whereas the open cell foam will allow air to pass through.  Closed cell has a better R-Value per inch of application but is more expensive to install.  So where is the common ground?  We have found that a hybrid approach works best for us and keeps the costs down.  In the 2×6 cavity, we spray a 1/2″ of closed cell foam on the back side of the sheathing and then blow in fiberglass batt insulation for the rest of the 5″.  The spray foam creates a great seal to repell any air infiltration and the blown in batts fills the gaps and delivers a great composite R-Value for a 2×6 stick framed wall.  It’s a great idea to also spray foam your band board in a crawl or basement.  The investment will pay dividends year after year and is well worth it.