Cellulose insulation
Rik27
| Posted in General Questions on
Hello,
we have rockwool exterior insulation and opted for cellulose in the interior of our new build in Wisconsin. I’m wondering if there is any benefit to clean fiber (cardboard boxes) vs regular cellulose. I like the idea of an ammonia free product without contaminants but want to make sure the company is legit and won’t go bust and has a good product.
anyone have experience with it?
we went with cellulose vs rockwool inside because it is easier to spray in and also protects the wood from rot and has some better moisture absorption (from what I understand).
thank you!
RIK
Here is a link to the product
https://www.cleanfiber.com/
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Replies
I'm not sure what you mean by "clean fiber (cardboard boxes)". If you just want ammonia free, there are other options (Greenfiber, etc.). Cellulose insulation is typically made from recycled paper materials. The primary difference with the ammonia free materials is the use of a different fire retardant (borates). You do get less corrosion risk as an added benefit.
Note that it isn't moisture "absorption" that is a benefit, it's "buffering". Cellolose can help to essentially "average" moisture levels over time, which is a benefit in some cases. If the cellolose ever gets saturated though, that's a problem, and rockwool (mineral woold) and fiberglass can dry out better in such situations. Overall though, cellulose is an excellent insulating material for some applications, notable attic floors.
Bill
https://www.cleanfiber.com/
This is the product - yes I get the buffering. Hoping we won’t have any leaks in the walls! We considered rockwool on the inside too but it seemed harder to install the bats and get a really tight fit.
You might also want to look at Timberfill if it's available in your area. It's manufactured from wood fiber and uses borates for fire/insect protection. Installation is generally dense-packed with the same blowers as used for cellulose. This is a dry install, not wet spray like some cellulose.
And, none of these products "protect" the wood from rot. You protect the wood by keeping it dry - no bulk water leaks, walls designed to limit condensation and promote drying, etc. Your design with Rockwool outside and something like cellulose inside is a great approach.
When we started the build I was not available and no one like to use stuff they are not familiar with!
https://www.cleanfiber.com/
This is the product
OP keeps posting links to the product, which made me think OP Is an advertising bot, and I was going to ignore this post...
However, looks like OP started posting in May 2025 about various things as OP goes through the build process, so may be legit.
OP: Most of how well insulation will do is related to the quality of the install. Damp applied cellulose is easier to install properly then dense packed, but even that is possible to mess up.
When you do settle on a product, suggest you reach out the mfg and ask to have a tech rep at the install to review the contractors install. I had GreenFiber cellulose damp applied and am happy with it. Even though the sub was technically their customer, I was astounded at how many issues the factory tech rep pointed out - installer had to come back twice to satisfy the rep, and I believe I got a much better install due to that.
Since it hasn't been mentioned, I'll add that one of the benefits of cellulose based insulation over mineral wool is that it has a substantially lower global warming potiential (GWP). In fact it can actually be rated in the negative, in that it sequesters carbon into the structure.
Cellulose can also be obtained as batts, for anyone who might not be wanting to do the spray applied approach.