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How much for damp-spray cellulose?

Can anyone with experience contracting damp-spray cellulose please tell me what it costs generally? Some project details would also be helpful. I'm researching a story for Fine Homebuilding magazine and it's tough to get pricing for damp-spray.

Asked by Patrick McCombe
Posted Oct 3, 2012 8:55 AM ET


12 Answers

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Whatever information you gather, remember that prices vary WIDELY from region to region. I have noticed that price variations are particularly acute for cellulose. In some areas, cellulose is common and affordable. Elsewhere, it is rare and expensive.

Here's information copied from a comment posted over a year ago (click here for a link to the thread) by GBA reader Danny Kelly, who lives in North Carolina:

"Hi Martin - just recently did this exercise for a presentation I was doing for some architects - here are a few for NC - all prices are per square foot installed and include the 15% price increase we got last quarter:
kraft faced fiberglass batts:
R-15 - .49
R-19 - .41
R-30 - .63
R-38 - .71
R - 30 blown - .48
R-38 blown - .58
Blown in fiberglass walls
2x4 wall - .65
2x6 wall - .90
Damp spray cellulose in walls
2x4 - .58
2x6 - .81
Open cell foam
2x4 - 1.00
2x6 - 1.40
roof rafters 5.5" (I know, I know, but that is what everyone does down here) $1.40 plus .75 when ignition barrier is requuired
Closed cell:
2" - 1.75
3" - 2.50
12" netted cellulose for double stud wall - $2.00
We get prices all over the place from one company to the next even locally, interested to see where others are coming in.
Answered by Danny Kelly"

Answered by Martin Holladay
Posted Oct 3, 2012 9:27 AM ET
Edited Oct 3, 2012 9:32 AM ET.


I followed the link. Danny is the only poster who mentions damp-spray. I wonder why it's so rare.

Answered by Patrick McCombe
Posted Oct 3, 2012 9:40 AM ET


A lot of builders are wary of an insulation method that adds moisture to the wall assembly.

Answered by Martin Holladay
Posted Oct 3, 2012 10:04 AM ET


Damp-spray cellulose will shrink after it dries, leaving a small gap between the cellulose and the framing members.

Wet Cellulose and Stud 2.jpg Wet Cellulose and Stud 1.jpg
Answered by Armando Cobo
Posted Oct 3, 2012 11:58 AM ET


Why does this photo look like it's been photo-shopped Armando?

Answered by Patrick McCombe
Posted Oct 3, 2012 1:13 PM ET
Edited Oct 3, 2012 1:55 PM ET.


Those are two photos -- one on top of the other. (Unfortunately, the GBA site doesn't insert any white space between photos when readers post multiple photos.)

Answered by Martin Holladay
Posted Oct 3, 2012 1:24 PM ET


Those are untouched real photos, from a real jobsite, that had been approved by a third party rater and building inspector. Is the same location, just one is a close-up. I think I posted several pictures of that same job on another thread here at the GBA.

Answered by Armando Cobo
Posted Oct 3, 2012 2:54 PM ET
Edited Oct 3, 2012 2:55 PM ET.


The amount of shrinkage of damp spray depends on the moisture content and density when sprayed, as well as the rate of drying. It's typically still tighter than batt installations, and it can be dense-packed with no apparent shrinkage or settling over time, but dense packing is more labor intensive and costs more.

Answered by Dana Dorsett
Posted Oct 3, 2012 6:08 PM ET


Gap only on one side of 2x4 for whatever reason.

Answered by aj builder, Upstate NY Zone 6a
Posted Oct 4, 2012 7:53 AM ET


What is the density of wet spray?

Answered by aj builder, Upstate NY Zone 6a
Posted Oct 4, 2012 7:54 AM ET


Looks to me like a case of a stud moving, not shrinkage. Note the cross member and how the gap is largest at the cross member and then tapers away. No gaps anywhere else.

One doesn't have to look hard to find examples of defects in any kind of insulation when installed incorrectly. I expect that with proper moisture levels (during spraying) and adhesive, damp sprayed cellulose reliably has no gaps.

Answered by Jon R
Posted Nov 3, 2017 1:52 PM ET
Edited Nov 3, 2017 6:07 PM ET.


I agree there are a number of mechanisms that could cause the separation. But with dense pack the springiness of the cellulose wouldn't allow that unless the stud moved a LOT!

But it's something to be aware of and inspect for when using damp sprayed cellulose. Cobo has stopped using damp spray altogether after discovering gaps using IR imaging many months after the house was finished.

Answered by Dana Dorsett
Posted Nov 3, 2017 2:05 PM ET

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