Monday, September 22, 2014
Insulation
performs many functions, but if we were to boil it down to two things:
1. Keep
the heat away during the summer
2. Hold
our heat in during the winter
Ridged insulation
and some spray foam can be air barriers if properly installed but, generally,
fiberglass, rock, wool, blown in cellulose etc is not an air barrier.
As we said before,
the key is to energy efficient buildings and environmentally friendly buildings
is the proper use of insulation. The amount of energy used to produce any
kind of insulation is over ridden by the energy saved during the life of the
building.
When using
fiberglass, do the best you can to make it “full fit” the cavity. Damp spray
cellulose will dry toward the interior so the interior will have to be designed
to allow that interior drying. Cellulose is not a vapor retarder.
Spray foams have
come a long way over the years. Many of them have excellent air sealing
capabilities. These foams can quite often reach the hard to reach areas and
give you a better insulation barrier. Think about building movement and the
tolerances required. Low density foams “move” better than high density foams.
