JLC · AUGUST 1989 Smooth installation and good performance rely on good prep work Cellulose insulation is a mixture of paper stock and chemicals ground together. The chemicals regard fire and inhibit corrosion. Cellulose is widely used to insulate ceilings and wall cavities in retrofits. More recently, it has grown in use in new construction, as well, in a wet spray-on form (see "Spray It," JLC/NEB 8/87). I've been installing spray cellulose insulation for some time now, and obviously I prefer it over fiberglass. I believe it makes for a tighter building. But the installation process is quite different than for fiberglass. If you decide to use this type of insulation in your houses, here are some tips