Looks like cellulose got an R-value increase
 

I was just looking over the list of different material's r-values on a site I like to go for for r-values:

ColoradoENERGY.org - R-Value Table

I happened to notice that loose cellulose is now rated at 3.6-3.7! I thought it used to be 3.2. Apparently a study was done and it found cellulose to be better than before. They also tested dense pack which got a little boost too to 3.8-3.9.

Here is the study that was done:

http://www.coloradoenergy.org/procor..._Truncated.pdf

Looks like we now have yet another (or a better) reason to go with cellulose.

Whether or not it became better, it still would be on top(IMHO). Versus fiberglass, dense pack stops the airflow within it that makes fiberglass not work so well. Versus foam, a slightly bigger cavity in new construction doesn't cost much but the foam sure does, not to mention the care it takes to actually foam it and the concern over the guy who has to chip it away to install some electrical or plumbing fixture in a wall. I'm probably just preaching to the choir. All insulations have their place where they are appropriate though.

... Said the guy with cellulose in his avatar:D

My understanding of the R value of cellulose is that it's about R 3.4 for dense pack and a little higher for loose fill. Loose fill is higher before it settles also. I'm getting this from Bill Hulstrunk, the engineer at National Fiber. Wouldn't surprise me if there were new evidence though. NF is less than 10 miles away from me so I've worked with Bill Hulstrunk on more than one occasion when building inspectors are being crotchety. Great guy and a great product. More fuzzy and less dusty than the stuff they have at Home Depot. Green fiber or something I believe it's called. The bag looks like a NF bag so I'm always fooled.

I thought cellulose wasn't recommended for exterior walls b/c moisture retention. aren't most batts for 2x4 walls rated r-13? I just saw rockwool batts at the store, which I thought was banned or no longer in use. They touted r-15 for 2x4 and claimed "superior fire protection". All I know is blown in rockwool is some of the worst stuff to work in and disturb in an attic.

I just insulated my back room with batting made from Roxul, which is a brand of rock wool. It is great stuff to work with, and it can be shaped quite easily by cutting with a serrated knife. It is quite dense, and when you push it into a stud wall space, you can feel the whoosh of air that is being displaced.

I found that mineral wool had none of the 'fiber glass itching' experience. However, I would advise wearing a partical mask when working with it, as a precaution.

I just did a Google search for "rock wool banned", and didn't turn up anything of significance.

What was your source for that piece of information???

And when you said, "touted r-15", I take it that you have information that suggests otherwise???

Could you please share your source of that information.

And your comment, "...claimed "superior fire protection"", was curious, too.


The gas stove I have in my kitchen is a used commercial stove, the burners are 24,000 BTUs each. In the photo above, I placed a heavy stainless steel screen on the burner and waited a few seconds for it to come up to full temp, then I took a sample of the mineral wool that I have in the back room, and put it on the red-hot screen. The photo was taken after 5 minutes of the mineral wool sample being on the red hot screen. During that 5 minute time, I saw no change what so ever to the mineral wool sample.

If you have any actual information that would bring into question the claim that mineral wool "offers superior fire protection", I'd be very interested to see it.

Other than that, I can't see that there is any substance at all to what you just posted.

Best,

-AC

AC hacker, I have no problem with rockwool, its generally more insulative than fiberglass. In fact I brought it up as an alternative to cellulose. Blown in rockwool from the 60's and 70's is some harsh stuff to disturb. The dark gray blown in rock wool fibers seem sharper, the dust is way more irritating and there's usually some shiny glass like shards mixed in. I haven't seen blown in rockwool at big box stores for sale in at least 10 years but I haven't been looking either. From wikipedia I found "some types of mineral wool are considered a possible carcinogen to humans, similar to asbestos" but thats probably similar to the california prop 65 warning I see sometimes on fiberglass. When I see 2x4 walls and batts I usually think r-13. Probably because thats the minimum code and seems to be the only thing people want to build to. I was actually happy to see r-15 batts for 2x4 walls for my personal projects. The packaging I saw with "r15 and superior fire protection" was in really large print, it was definitely touting. Tout Definition
dictionary.search.yahoo.com
v. verb

To promote or praise energetically; publicize.

To solicit or importune.

If you check the link Daox shared, at ColoradoENERGY.org - R-Value Table, they rate fiberglass batts 3.14-4.30 r per inch and rock wool batts at 3.14-4.00 r. I noticed they don't have a listing for dense pack blow ins.

gtojohn,

Don't worry, it's only credibility.

-AC

High density cellulose doesn't burn in the wall. And it quickly distributes any liquid water so that it evaporates and won't cause problems. For new construction, that is the way I would go.