I am insulating my house, going with R38 Fiberglass batts (single faced) in the attic. I will have a decent amount of Mineral wool 1.5" thick and 7" thick that ranges from R5 to R30 respectively. I don't think R-38 in my zone 5 is super sufficient in terms of cutting energy costs but I do not have the money to buy more fiberglass or cellulose to add to the top. Consequently I am thinking about adding my leftover mineral wool to the attic on top of the fiberglass. It would not be enough to cover the entire attic floor though. I also don't know if it would interfere with future insulation? The brand is owens corning and it's rock fiber just like the Roxul stuff.

The other option I have is to use it in my interior bathroom and bedroom walls for sound deadening.

Any thoughts?

1 Answer 1


Either idea will work. If you lay the stuff on top of the attic insulation, anyone (yourself included) who wants to add more insulation in the future can just flow in cellulose or loose fiberglass on top of it, easy least.

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