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Colocano 10-17-2011 08:48 AM

Blown in insulation below?
Hello to all,

First time here and could really use some good advise.
I have an older home, which has no insulation.
I am going to gut out my entire bedroom to redo it all.
Now my thought is to blow in insulation to fill in the exterior walls below, which is my livingroom which also has now insulation.
The plaster in my living room still looks good so not looking to demo that anytime soon. Have read that in order to use blown in insulation I would need a vapor barrior. Is this a MUST? Can I get away with another method of insulation for the room below?

For my bedroom, am going to use fiberglass batts.


nealtw 10-17-2011 05:14 PM

Unless you have really old house, the upstairs wall will not give you access to the cavitty down stairs.

Colocano 10-18-2011 09:11 AM

Insulation Below?
Yes, it's a pretty old house, and I do have acess to the bottom (First floor). I have run new electricity straight down from the attaic to the basement. This is why I was hoping to just blow insulation down without having to open the plaster walls in the room below. Is there such a thing as Dry Loose insulation that I could use? with out having to do a vapor barrier?

nealtw 10-18-2011 03:24 PM

Vapour-Barrier Materials

On this site they talk about older houses having oil base paints and vapour barrior.
I would also suggest after you havge insulated, you should block all thoughs runs top and bottom, they are a free ride for fire from basement to attic.

Colocano 10-21-2011 08:01 AM

Thanks for the link on the vapor barrier.

However, my question still remains to anyone who can help.

I want to blow insulation down into the walls of my living room.
I have read that the wall should have a vapor barrier, especially b/c of the moisture in the insulation.
I spoke to an insulation contractor and he assured me that moisture would not be an issue. I am concerned he is saying this just to get the job.

Can I just go to a home center buy loose insulation, rent the machine and blow insulation down into my plaster walls? Or is there a good chance of creating a moisture issue?

Thanks !

nealtw 10-21-2011 09:50 AM

I think your guy is right, you don't have a problem.

GBR 10-23-2011 01:11 PM

If using cellulose blown-in , no v.b. is required.

Depends on the outside wall make-up for vapor barriers: Chapter 6 - Wall Construction

In most of the U.S., no vapor barrier is required as a vapor retarder will do- where are you located?

Chapter 6 - Wall Construction

Dionysia 10-28-2011 06:58 PM

We used blown cellulose insulation on our 1920's bungalow about 10 years ago and have had no problems. If you have the lathe and plaster walls, there is a good chance you have enough layers of paint and/or wallpaper not to worry about it.

It also sounds like you have a balloon-framed house, which means your walls are a series of chimneys for any fire that might happen. The house my husband is renovating is balloon framed. At some point in its history there was a basement fire that ran up through the walls and scorched the skip board in the attic. You definitely need to take the opportunity to put in fire breaks.

The easiest way to fireproof between the floor levels in the exterior walls is to buy enough rock wool insulation batts to stick a 6 inch to 1 foot piece in each bay between the ceiling/floors. Otherwise you need to put 2x4 stops in each bay, which would be difficult without the walls open.

Another thing to consider is that the lathe in a ballon framed house lent stability to the 20 or 30 foot studs that make up the walls. You may need some additional bracing in your walls to make sure you don't get cracking in your drywall when you are done. The above-metioned house had all its lathe and plaster removed before we got hold of it, so I don't have any direct before/after experience, but the whole house would shake in the wind and is slightly twisted from foundation to attic. We will fur out the 2x4s to 2x6 depth for additional stability and to fit more insulation when we get to that point.

joecaption 10-29-2011 08:53 AM

Real wood blocking would have to be added in each stud bay in the crawl space or basement to prevent the insulation from just landing on the ground, It's far better to have the insulation blown in from the outside walls not blown in from above. They use a hole saw to make round holes, shoot it in and plug the holes when done. The reason being is, there's no way to make 100 % sure the insulation is going to reach all the way to the bottom of the wall, and no way to get it in under the windows.
As the insulations falling it's going to want to catch on all the wood fibers sticking out and any wiring going across any stud bays.
I see this all the time when I have to replace old rotted clapboards on old houses.
Most also had what's called diagnals built into the corners where I've yet to see anyone insulate.

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