[bpape]

To deaden a cavity, you don't need anything particularly dense. Do you know what it was (brand, model, density?)

If the cans are not IC rated, you should still give them a bit of space.

Bryan

 

[bpape]

If you can just get the brand and what 'model' it is, I can get what density it is.

4" should be plenty of airspace.

 

[bpape]

Homasote is not what you want by any stretch. It's more for exterior sound isolation - and not all that good at that. I don't have a listing for anything '1200' in Johns Manville - sorry. How flexible is it at a 2' thickness? I'd guess it's likely somewhere between 2.5 and 4.5/cu ft density so a little less to a little more dense than OC703.

Bryan

 

[bpape]

The mineral wool will likely be fine - I was just referring to the Homasote. Quite honestly, for the money you'd spend on dense mineral wool vs insulation would likely be better spent on another layer of drywall.

Bryan