Blowing cellulose

1740 Views 5 Replies 3 Participants Last post by Gary in WA, Feb 13, 2013

Master Brian

Discussion Starter · Feb 12, 2013

Let me start by saying I realize this has been touched a lot online and people seem to get somewhat slammed for the idea, BUT....I have an old, very uninsulated house (c.1915) and thus I get little insulation projects that aren't worth calling out a pro and/or getting use of a rental machine.

With that said, I'm currently, topping off an attic space above my pantry with some cellulose. I had blown with a machine a year or so ago, and have removed some plaster from kitchen and see that I missed some areas, so I've been topping it off best I can. Problem before was just good access!

Looking online I found someone had used a shop vac and a bucket, putting the chopped cellulose in the bucket and blowing it in that way. I figured for this job, what did I have to loose. It does work well, albeit it isn't very fast and I have to preloosen the material with a paddle style paint mixer before hand. It comes out very fluffy, so I figure it'll work. Definately an improvement over before!

Now for the Million $$$ question.....I have a squirel cage from an old furnace that moves A LOT of air very forcefully. I've actually built a box for it and use it to filter air while creating dust during various remodel jobs I've done. I am wondering what would happen if I built another box (or used trash can with lid) and blew air into the box filled with loosened up cellulose and used that to blow cellulose. Any chance it would work? ....what about dense packing walls with it?

I figure the dense pack part will be the biggest what if, but wouldn't a furnace squirel cage move air as well, if not better than most rental machines? I dense packed most of my exterior walls about a year ago with a rental machine, realizing it may not be as perfect as a professional job, but better than nothing and it has made a big difference on sound deading and draftyness of the house. Now I need to go in and do above windows and a few joist bays....figure I'll see if any settled while I'm at it.

If it works decently enough, I have an old elctric motor, I could always rig it to 'fluff' insulation in the box as well.

Thought? ....am I crazy for thinking this may work and/or has anyone tried something like this? I just need a way to get 3-5 bags into spaces when I get to them.

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HomeSealed

· #2 · Feb 12, 2013

Yes, you are crazy,:laughing:
You can probably get by with some sort of contraption for loose fill, but dense packing is far more of a science and needs pressures adjusted properly, etc. Rental machines really don't even do a good job of it, but given that you had no insulation at all, it at least got some in there. I'd be willing to bet that with a blower door hooked up you'd see a bunch of missed spots on a thermal cam.
It is your time and money so have at it if you'd like, just don't expect an fantastic result... and I really would tell people that it is truly "dense packed" or expect the corresponding r-value.
Given the age of your home, has your electrical been updated? If you have knob and tube wiring the insulation is a serious safety hazard.

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Master Brian

Discussion Starter · #3 · Feb 12, 2013

As far as the walls are concerned, like I said, they may not be perfect, but I did a fair amount of reading up on this prior to having done it and I think I'm pretty close to what the specs would call for. Again, maybe not perfect, but I tried using the 'finger' test, which seems to be a good indication and the spots seemed fairly tight. I doubt I have any major voids in the walls as I pushed a 1" tube, which I marked for length to be certain I hit bottom, and filled until the machine bogged down and slowly moved up. I didn't just drill hole and spray in. I also payed attention to the number of bays per bag. If memory is correct, I read that 1 bag should do about 3) 16" OC 8' high bays. I have 9' walls and seemed to get about 2-1/2 bays per bag.

Maybe I'll do a mock setup and see how it performs, I have pretty much all that I need, minus the hose....

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HomeSealed

· #4 · Feb 12, 2013

When I was trained they had us fill cavities with plexiglass on one side and you would be surprised how much is missed if it is not done very thoroughly and with proper equipment as things get filled over and around wires etc and leaves gaps if there is not the proper pressure. Either way, as I said earlier, it is certainly better than the empty cavities that you had before, so you should feel good about that. Did you accidentally fill any cold air returns? If not, you are a step ahead of a lot of pros!:yes:
I noticed that you did not mention anything about my electrical question... If you have knob and tube wiring, you need to get that addressed ASAP. It is a major safety issue.

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Master Brian

Discussion Starter · #5 · Feb 12, 2013

HomeSealed said:
When I was trained they had us fill cavities with plexiglass on one side and you would be surprised how much is missed if it is not done very thoroughly and with proper equipment as things get filled over and around wires etc and leaves gaps if there is not the proper pressure. Either way, as I said earlier, it is certainly better than the empty cavities that you had before, so you should feel good about that. Did you accidentally fill any cold air returns? If not, you are a step ahead of a lot of pros!:yes:
I noticed that you did not mention anything about my electrical question... If you have knob and tube wiring, you need to get that addressed ASAP. It is a major safety issue.

No cold air returns on exterior walls, so nope didn't fill any of them. Also, all of the electrical has been redone, no knob and tube left and all exterior walls have the wires, coming up from the bottom of wall, so no real areas for wiring to catch any.

I did fill one wall that I left the lathe intact, but removed the plaster and it was 100% filled, hasn't settled and has decent coverage.

Thanks for the feedback! I am not a huge fan of fiberglass batts, so I figure I'm ahead of that game as well!!:wink:

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Gary in WA

· #6 · Feb 13, 2013

http://www.karg.com/pdf/Insulaton_density/Dense_packing_Allwein_and_Biddle.pdf

http://www.karg.com/pdf/Presentations/Dense_Pack_Cellulose_Insulation.pdf

Gary

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