Insulating Attics with Blown In Cellulose Insulation
Today I’d like to tell you about the cellulose attic insulation being installed in the Energy Star home that we’re building for a client. Blown-in cellulose insulation is an excellent way to insulate your attic space. In my opinion blown-in cellulose is a much better product compared to fiberglass insulation.
Cellulose insulation is made from recycled newspapers. By using a recycled material cellulose insulation is certainly a very green building product! The recycled newspaper is treated with chemicals such as sodium borate, boric acid and ammonium sulfate to make it fire retardant. The chemicals also help make the cellulose insect, rodent and mold resistant.
As you can see in the photos we’re blowing the cellulose into the attic space with a flexible hose. The insulation sub-contractor has a special box truck with a giant blower system and hopper. The guys dump the cellulose into the hopper and it’s blown up through the hose into the attic. This is a really dirty job and one that requires proper breathing and eye protection.
Blown in cellulose out performs fiberglass for several reasons. However, the most obvious advantage is the ability to blow cellulose all around penetrations, framing materials, light fixtures and obstructions.
If this attic was insulated with fiberglass batts, it would have voids above each truss bottom chord member. With blown in cellulose you have insulation surrounding every single framing member and utility.
Cellulose achieves an R value of approximately 3.5 per inch. In this house we’re installing a minimum of 15″ of cellulose with a settled depth of 14″ for an R value of 49. Around here the minimum R value by code is 38 (for most situations). So you can see by using the cellulose we’re achieving an R value that’s almost 30% better than the insulation required by code.
So if you’re building a new home or thinking about adding additional insulation to your attic then I suggest you look into blown in cellulose insulation. I have it in my new home and every house we’ve built that has it out performs the houses with fiberglass.