What is best insulation material?

According to Walter R. :

State of the art is blown foam. Very expensive tho.

Cellulose still has a tendancy to pack down, and does bad things if it gets wet. Fiberglass much less so. Rockwool (eg: Roxul) essentially doesn't at all, and costs about the same as fiberglass but availability is spotty in the US. It's also a lot more fire resistant than either cellulose or fiberglass.

Also known as "spray foam". It goes on liquid, then expands and hardens. Also doubles as vapour barrier and blocks airflow.

Roxul is great (used it in my utility room for noise control), but around here in Canada it commands a 20-30% premium over fiberglass batts, and more than that over blown-in fiberglass.

When I did my garage attic, it was cheaper to contract out for blown-in fiberglass than to buy the fiberglass batts and do the labour myself.

Chris

Especially in California you are restricted to what you can use. The best insulator is a vacuum. I prefer the non-itch fiberglass batts. In S.CA, you don't need much insulation, but I'd get the highest R-value I could find unless I plan to move soon.

closed cell foam is over R6 per inch, pricey but effective

cuts noise transmission and air infiltration, self vapor barrier. all positives except price

Of course, his house would have burned down with foam insulation, but no problem

Bob

Blown in, stabilized cellulose is the only way to do an attic. It's cheap, fire retardant, and insulates better than fiberglass.

check out

Good cellulose insulation won't burn at all.

steve

Hogwash.

Cellulose is paper, it degrades to dust, a roof leak ruins it, it settles alot.

There is no one best. Each have their strong points. Each application and area of the world may call for a different "best."

They pulled out the fiberglass-batten insulation that was between the

...

Odor abatement would be my guess...

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It only doesn't burn because it's been treated with flame retardants.

From what I've read, there are some doubts as to the durability of the flame retardants, and no test exists to verify how long they last.

Chris

Why would they go away?

oh really? what part? of the three items i mentioned, what is not correct?

1. I've just let out a few cubic yards of it that were put in in 1958. None was degraded.
2. Why would you let your roof leak?
3. stabilized cellulose does not settle.

you people are only hurting yourselves by keeping your head in the sand. I'll keep using the cellulose, spend less money, have better insulation.

thanks for your input

steve

According to Steve Barker :

Evaporation, sublimation, etc. etc. etc.

They are only retardants. They generally _aren't_ fire proofing.

Bob