# DIY Dense Packing Cellulose?



## Arky217 (Aug 18, 2010)

dalesizemo said:


> I live about 40 minutes southwest of Atlanta, and have had trouble finding a contractor nor a machine to do the dense pack cellulose for our new home i am presently building. We have double walls, both sheathed with OSB, the interior wall sheathed on the outside to give an open interior wall cavity to run wiring, etc. The walls are separated by 4 inches, allowing for 7 1/2 inch cellulose to be dense packed in between. The top of the two walls are open to the attic space where I plan to blow in about 20 inches after filling the walls. Now for the question:
> 
> 1. Since finding the machine nor contractor seems possible around here, should i just blow the insulation in with the regular machine and make a 2 x 4 tamper to occasionally push down the blown in cellulose from the open top of the wall? I haven't closed in the windows yet, planned to put 3/4 plywood to join the two walls out to where the windows will be installed, but right now could blow insulation easily below window opening and then pack it down, blow some more, etc.
> 
> ...


I had this same dilemma; no one in my area did dry dense blow cellulose and no rental place had the blower that was powerful enough to do the job.

I just finished my walls and it turned out well, however, I must warn you that if you are working alone, my method will take a long time. It does, however, leave you with a wall that is uniformly packed throughout.

My walls are 6" thick on 24" centers and the house is 24' x 48'.
I ended up using 1650 # of cellulose.

The way I did it was to cut a 4' x 8' piece of OSB into 5 pieces of 16" x 48" and 1 piece
of 6" x 48"; I also bought a 4' x 375' roll of poly mesh. 

I would cut off a 8' length of the mesh and staple it to the bottom of 2 bays and up the studs 16". I would put a temporary staple in the top end of the mesh to hold it out of the way while I then attached the first 16" x 48" piece of OSB at the bottom of the bays using a couple of drywall screws in each stud. Then I pried out the staple at the top of the mesh and let it lay on the floor.

Using a half gallon plastic scoop, I would put 3 scoops of cellulose in each bay.
Then using an 8" length of 2x4 that had a 2"x2"x12" piece of wood attached to the middle of one side of the 2x4(made like a plunger), I would press the cellulose down in each bay.

Then repeat until you reach the top of the piece of OSB.
Then staple another 16"; add another piece of OSB and so on.
After 5 pieces of OSB, add the 6" piece and use a 2x4 with a shorter handle.
For the last 7" of the bays (my bays were 93" high; 16"x5=80+6=86, that leaves 7"), I
would staple the mesh leaving just a corner open and pack the cellulose in by hand.

Then remove the OSB, compress the cellulose a little with a roller (a paint roller would
probably work just fine; I used the roller that came on the end of material holder like you would use to support long lumber when cutting the end with a miter saw).
It doesn't take much; just enough to keep the cellulose from bulging out the drywall.

After finishing the 2 bays, I would then install the drywall before continuing on with another 2 bays.

Of course, you have to cut out openings in the OSB for the electric outlets and switches
and for any 2 bays that are narrower than 48", save them for last as you will need to cut the 48" OSB pieces shorter to match.

Now, the longest part of this method is shredding the cellulose.
I first tried putting some chunks of cellulose in a barrel and used a large drill with an aggressive paint mixer paddle; this was very slow and didn't work out at all.

Then I made a wooden box shaped like an inverted pyramid and put 1/2"x1" wire mesh across the top. I added some 4" high walls around the perimeter to keep the cellulose from brushing off the edge of the mesh.
I made a stand for the box so that I could slide a plastic storage tub under the bottom.

Then it's just a matter of taking chunks of cellulose and rubbing it across the mesh until
you fill the tub.
You need to use gloves and especially you need a good respirator mask.
You will also need to use the mask when you are filling the bays.

I've heard it said that the cellulose needs to be packed to at least 3.5#/cu.ft. in order to
not settle and leave a gap at the top of the bays.

Using this method, you will actually have to press very lightly to even stay under 5#/cu.ft.
I think that I averaged about 5#/cu.ft. on mine.

The method is slow, I admit, but if you had a one or two helpers keeping you supplied
with the shredded cellulose, it would actually go fairly fast.

One thing for sure, you won't have any weakly packed areas with this method.

Best of luck,
Arky


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## dalesizemo (Sep 17, 2012)

That sounds pretty intense! I was just going to rent one of the local Lowe's machines by buying the minimum number required (will buy a bulk amount from a Regal supplier) and blow in a foot or so in between the already nailed in place OSB walls ten feet high. My toughest area to compact will be along the walls between the gable ends which have a 4' height above the walls to work with, though i do have the window openings i mentioned and door openings in both of those walls as well. Sounds like it will work, and I have the added advantage of not having to worry about outlets, etc. being cut in, since my inner wall cavity is open for all the plumbing and electrical. 
Thanks for the detailed description! I may use your idea of the 16" at a time on the window and door opening edges that have to be closed in connecting the two walls.


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## wisnoskij (Apr 25, 2018)

What do you mean by "#"?

"I ended up using 1650 # of cellulose."
" 3.5#/cu.ft."


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