[JuancoRocks]

Cellulose insulation has it's own drawbacks, most of which are not well publicized.

Cellulose is made with chopped newspaper that is hammermill treated with boric acid and borax.

While it is cheaper than rock wool or fiberglass it has it's own design defects. Under extreme heat conditions as here in Arizona the boric acid and borax migrate down in time and then leave an attic full of exposed unprotected chopped paper. Makes a beautiful flashover when exposed to fire. There is also the fact that the boric acid and borax mixture is corrosive and should not come in contact with metal ducts, pipes or light fixtures.

Yeah, I know, in many cases it has a UL listing. Well, many things that are listed work well in other climates and other parts of the country but Arizona seems to be the ultimate test facility and by default many of those things fail here. We did an accelerated life test and ended up with exposed newspaper. Not what I want in my attic.