After the radiant barrier was all installed, it was time to put in the wetpack cellulose insulation. At 86 MJ/m^3 , it is a much lower embodied energy insulation than either fiberglass bat (336 MJ/m^3) or the polyurethane insulation (2160 MJ/m^3). While it is not quite as high a performance an insulation as the polyurethane, we are installing it in 6″ thick walls which means we’ll have plenty of insulation with its R value of 3.7 and its nice ability to fill in all the small spaces around wires, pipes and electrical boxes.
Blowing it in is a messy job with one guy spraying the cellulose mixed with water, binders and a fire retardant into the cavity, and another guy sucking up the excess to be run through the mixer machine and blown in again.
Down at the truck is the machine that powers all of this with another guy busy dumping in more cellulose mix into the big hopper feeding the blower hose.
When the cavity is finally filled, it is leveled off and left to dry. In thin areas, the cellulose is blown in behind a mesh to keep it in place.
In one place in the house you can see the three major types of insulation we are using – cellulose, straw bale and foam insulation all meeting up in one spot.