Blow in wall insulation

Jan 24, 2008 22 Replies

What is the process to insulate a interior wall with blow in cellulose? I'd like to insulate an interior wall to deaden the noise coming through it. I'm not sure if it's worth renting a machine just to do a wall. Is there another way?



Thanks.


If you will be doing it from the inside, drill a hole top and bottom of each stud space. You might get away with only 1 hole for each...

Now, promise you won't laugh...

I had one wall to insulate and couldn't see renting the machine, so.....we used an electric leaf blower!! Yes!

Ran the blower outside the house with a hose into the room. Fed the material right into the blower intake by hand. Worked like a treat!

YMMV

Humm, interesting. Now I have to ask, how did you attach the hose to the leaf blower? Also when I blew insulation in my attic a few years ago, we fed the insulation into the machine, which had a hopper. Then it was "torn up" and then forced into the hose and viloa.

Also, if I remember correctly, the hose diameter on the machine I rented was a few inches, I hope I can use a much smaller diamter hose. I don't want to make large holes in the walls.

So I have to go from the bottom and top of the wall?

Good grief, Dude, are you out of duct tape? That will do the job in a jiffy...the universal adapter. Cheers,

Joe

Cellulose in walls may settle 15-20%, there is a Wet process where Glue is added so it does not settle,

We bored holes that were only 1 1/4" or 1 1/2" diam. Adapted a small size hose to fit the blower outlet using... Duct Tape!

The 2nd hole allows air to escape. Without the 2nd hole, the fill in the wall will be only partial.

Jim

But how is it "decompressed"? The insulation comes in compressed bags.

Well, since this is just for sound deadening purposes some settling I think will be fine.

By hand. The outside "operator" grabs a handful from the bag and squeezes it a bit as he feeds it into the blower.

Speedy Jim wrote in news:h76mj.5964$EZ3.342 @nlpi070.nbdc.sbc.com:

LOL!

...oh that's right. You said not to laugh. Was the hose duct taped to the blower? Sounds like a future Red Green episode.

Yes, hose duct taped to blower outlet.

You're right! Perfect episode for Red Green. On the show though, the hose explodes, sending cellulose dust everywhere!

Jim

Real sound deadening is done with a "Floating Wall" one not attached to the existing wall, Cellulose may not do the trick, look for "db' sound reduction ratings

I bet with duct tape and cardboard you could even make a larger hopper for the material... Oren

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Don't think that will do much good.

The sound vibrates the outside wall. The outside wall vibrates the studs. The studs vibrate the inside wall.

If you had an outside wall, no studs, and an inside wall, there wouldn't be much sound trasmission at all.

Which brings to mind the fix: A free-standing additional wall, not connected to the existing one.

In the wrong hands duct tape is dangerous. A federal officer went to jail for taping a spitting felon's mouth shut. He died. Now it's the law, not to tape their mouth shut.

Oren

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Actually, cellulose is the best sound deadener and sound insulation for wall cavities. It's mass and weight are the reasons, but it does work to reduce sound transmission through the wall. True sound elimination would require further steps, but to reduce it, cellulose is the way to go.

We use it in bathroom and utility room walls to help reduce sound transmission and it works quite well. If you hear it with and without, you will become a believer.

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If your only goal is to reduce noise, I would suggest adding a new layer or two of drywall.

Check out

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In general you want to block air exchange. Air caries sound very well. (Try opening your car's window as a train is going by.)

Next you want weight. Heavy things (drywall lead sheets etc.) block sound well.

You also want to prevent any direct solid connections. Stagger wall studs or use special isolation devices to keep the sound from traveling through the wall (remember the two cans on a string (well wire actuarially worked) you want to break the wire).

Filling in wall cavities with sound absorbing materials (acoustical fiberglass bats) will do a little.

Point source control (special absorption material) at the source of the sound will also help.

Watching my neighbor's house being insulated recently, they drilled holes 1/2 way up and near the top of each stud space. They blew it in the lower hole, then the upper.

When mine was done years ago, they just blew it in from the top.

In each case, they had a tapered nozzle at the end of the hose to match the hole size (1" on mine, 1 1/4" on the neighbor's).

Bob F

Oren wrote in news: snipped-for-privacy@4ax.com:

LOF'n L!!

Oren wrote in news:qj2ip3tgga2galgqsc1nqf4ipfo2pcogmj@

4ax.com:

...without immediately ventalating with a .38. Think that's in the Soprano's FAQ.

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