GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Walls & floor: Roxul or cellulose?

user-959871 | Posted in General Questions on

My house is one story, 24×48, with 2×6 walls and 2×8 floor joists.
It sits on 3′ posts with an open crawl space.
The location is western Arkansas.

The wall sheathing is Zip panels; vinyl siding will be applied directly over the Zip panels. The drywall is not installed yet on the walls.

The subfloor is Avantech T&G. OSB will cover the bottom of the floor joists.

Roxul batts for the walls and floor will cost $2,200 just for the Roxul (with me doing the installation).

A company will blow cellulose in the walls and floor for $1,150.
(They seem to be the only co. around this area that does this)

Financially, it seems like a no-brainer, but is cellulose going to be better for this situation than Roxul. (Especially for the floor)

How can I tell if the cellulose installer is blowing it dense enough to prevent settling ?

When I asked him if he installed it to 3.5 lbs/cu.ft., he seemed confused and said that he had no idea.

What to do ? (can’t rent a high pressure blower around here)
(Can’t afford any type of foam, neither blown nor panels)

I would actually rather have cellulose, but not if it will be loosely blown like in an attic.

Opinions ?

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. user-757117 | | #1

    I found myself in a very similar circumstance (I even had the same conversation about dense-packing with several local insulation installers) except that I just didn't want to use any foam where it wasn't absolutely necessary.

    I ended up going with Roxul batts for the walls. Rock wool is a good material and if you're installing the batts yourself you can take the time to fit them properly.

    I'll rent a blower and do loose-fill cellulose for the attic floor though.

  2. jklingel | | #2

    similar answer on the diy forum.

  3. user-869687 | | #3


    Maybe you could help this cellulose installer out by having him read Martin's article:
    If he can do the job well and save $1,050 vs. Roxul, that should be your best option. But if you're unsure of his ability and you're willing to put in some effort installing rockwool batts carefully, that would be good too. I'm surprised by the cost difference because in my area they carry Roxul at lumberyards and the price is competitive.

  4. GBA Editor
    Martin Holladay | | #4

    You're in a tough position. For those of us in New England, where cellulose installers have been dense-packing walls for 25 years, it's hard to imagine that there are cellulose installers who have never considered the question of installation density.

    If I was talking to an installer who was totally clueless about his chosen profession, I would definitely back away and find another way forward.

    Note to cellulose manufacturers and manufacturers of blowing machines: your industry badly needs to focus on training.

  5. user-723121 | | #5


    I second your opinion on the need for training of cellulose insulation installers and would expand that to all types of insulation, pride in workmanship still means something.

  6. BobHr | | #6

    I am a big proponent of dense pack. There are wires, outlet boxes, etc in the wall. Up to 40% of wall cavities are not a full 16 or 24 inch on center. There are so many obstacles to doing a good job. I just think that you will get a better job with dense pack.

    I would look at the equipment the installer is using and if it is capable of dense packing. You should be able to calculate how much insulation needs to be installed.

    I think the question is will the installer be willing to take the steps necessary to dense pack. Do they have air pressure gauge to cailbrate the machine or will they be willing to buy them.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |