# Was Asbestos a good insulator?



## borzym60 (Feb 18, 2015)

Aside from the dangers of making it airborne, is asbestos a good insulator and what is the R value?

I have a ceiling joist between the first and second floor that are packed 8" deep with asbestos.

So much that it is very sound deadened. 

I recently insulated my cap cod upper bedroom and completely sealed the knee walls from the none controlled dead space behind the knee wall.

I'm concerned heat is being lost from the floor underneath escaping out into the none controlled space behind the knee wall.

Like I said though, the floor joist are packed tight with 8" of compressed asbestos. 

Leave it alone or what should I do?


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## Windows on Wash (Aug 30, 2011)

It was pretty good at the time given the fact that it is impervious to fire. 

If you don't need to disturb it, I would leave it. It works pretty well and depending on the fiber and type, is consistent with currently loose fill insulation R-Values.


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