Published by Hubert Den Draak under Building Supplies, Green Building

We do house tours here at the Nolalu Eco Centre in Ontario, Canada, and whenever a group comes into the garage, I can pretty much count on someone looking up to the ceiling and asking, “what is that gray stuff up there?”

OK, now you know that our garage ceiling is still unfinished. But it’s good that you can see the insulation through the vapor barrier, though it’s not the “pink stuff” most folks expect to see. That’s usually the cue to tell our visitors about blown cellulose. “Blown what?” Cellulose, sir. Just a fancy word for super-shredded recycled newsprint that we blew into our ceiling with a hose from an electric pump mounted on the back of a truck.

We did it ourselves, and it was probably the most fun I had building our straw bale house after stitching the straw bale walls. It was cool to see the cellulose spurting like a liquid out of the 4-inch hose, streaming all over the ceiling and effortlessly filling even the tiniest of cavities. (That’s a guy thing, I guess.)

One of the best things about cellulose insulation is the lack of pollutants or attendant mess. There is no off-gassing of carcinogenic fumes, no puffy eyes, no runny noses. Just a bit of fine dust.

We looked at other green options, from straw to hemp fibers to recycled cotton batts, but blown cellulose made the most sense for us. In a nutshell, cellulose:

• Offers the best insulation ratings available (R55 for our house)
• Is a fully recycled product, made from newspaper print and packaging cardboard
• Has the lowest embodied energy compared to other insulation materials (slightly higher than straw)
• Costs only about 12% more than standard glass fiber—and that 12% will be recouped within two to three years, thanks to its highly effective insulation characteristics (R55 for cellulose vs R19 for glass fiber)

Insurance companies like cellulose, too. The borax-treated cellulose works as an effective fire retardant, while other insulation materials actually feed a fire as it roars through the building. The cellulose’s powder-like texture discourages air from moving through it, so a fire has a hard time finding the oxygen it needs to keep going.

There are different brands of blown cellulose available on the market and all are subject to the strict standards established by the Consumer Products Safety Commission. Federal law prohibits states and local jurisdictions from adopting less stringent requirements.

And as for as our unfinished garage ceiling: we’ll leave it just the way it is. Someday, people will recognize what that “gray stuff” is.