Insulation, Radiant and Vapor Barriers - Blow in Cellulose over fiberglass

I want to supplement my blown-in fiberglass insulation in my attic. Can I blow in cellulose over the fiberglass?

why not just blow more fiberglass over it...Fiberglass weighs less and will not crush the existing fibrglass...

For instance if you blow cellulose you will crush the fiberglass and it will not be as effective, so you would need to increase the amount of cellulose to make up for the difference lost in the existing fiberglass...

Either product will do a great job for you, but in your circumstance I would go with glass...

How thick is the current insulation? in inches?

Where do you live?

In this area S. E. Michigan R-38 is what most qualified insulators would reccommend...

Also make sure when you increase your attic insulation with either fiberglass or cellulose, to be sure that you maintain proper air flow between your soffits and roof vents.. It may be necessary to install styrofoam vents at your eves if you have soffit vents in your overhangs..

Good Luck

Jim

I live in Tennessee, Local codes call for R30. I have been doing some work and the mush of the fiberglass has been compressed and otherwise distrubed. I wanted to do It myself and cellulose in the only type I can obtain. Styrofoam vents are already in place.


Thanks for the help.

See my answer to "alconte", the question above yours.

Thanks.