Hi tammys,

I don't know the context he was 'in' when he said that fiberglass doesn't hold it's R-value. Sure, if you compress ANY type of insulation, its R-value drops, or goes away completely.

W/O the attic fan, there is no 'dust' problem in the attic for the rest of eternity. HOWEVER, I don't know how that's affected if you have an attic fan. Attic fans that are built into the attic floor will blow air around in the attic. And I can't say anything either about any temporary dust problems during the install. As a precaution, I'd move the cat OUT of the house and consult a Veterinarian.

Fiberglass is fine, IMO. Just don't compress it because it WILL lose it's R-value. My best to ya and hope this helps.

Jay J -Moderator

PS: God BLess America!

tammys, fibreglass is a known lung carcinogen, and having it stirred up by an attic fan is even worse than with cellulose.
Just use a vapour barrier under the existing fibreglass, and place plywood on top of the floor joists so the insulation won't be stirred up. Throw out the moldy floor boards. Mold is a serious health hazard. It's imperative that you add a vapor barrier and increase attic ventilation to prevent it.

Which way does the attic fan blow? If it is drawing air from the attic to the outside, it seems that it would draw the dust outward.
If you have mold problems, you probably need more attic ventilation. Ridge vent being the best.

My father in law has cellulose in his walls and attic and he has not complained about more than normal dust in the home (5 years old).

All insulation is good as long as the "loft" is not compressed. J Mansville insulation advertises a batt insulation that is formaldhyde free that comes wrapped ina dust free package.

Cellulose usually has boric acid as a fire retardant. This is also a bug killer. Boric acid is 6 times LESS toxic than table salt. It is made of recycled newspaper. No cancer causing ingredience.