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Bow-in cellulose in plastered walls

grandpamike's Avatar

Join Date: Dec 2004
Posts: 9

11-07-05, 12:31 PM   #1  
Bow-in cellulose in plastered walls

We are working on this 1927-vintage 2-story colonial. The walls are hollow, no insulation. We are planning to blow in cellulose insulation through 1" holes drilled from inside. I read about this 2-hole method, where you drill a hole near the floor and a hole near the ceiling and you blow in through the bottom. The write claims it will settle better that way. Why not just go from the top, through a single hole?
The wall are plaster over lath, so drilling twice as many holes is twice as much work.
Your advice will be appreciated.

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jurched's Avatar

Join Date: Jul 2005
Posts: 124

11-07-05, 01:24 PM   #2  
In addition to that...

I'm interested in the same answer, as I have plaster walls and want to blow some insulation into the exterior walls.

In my case, I have tin mesh wire lathing behind the plaster. Really hard to get through that stuff, even with an axe!

As Mike was asking, how are two holes really needed?

What size hole is needed to blow insulation in there?

And, what's the best way to patch a hole?


Concretemasonry's Avatar

Join Date: Mar 2005
Posts: 6,125

11-07-05, 01:39 PM   #3  
Bow-in cellulose in plastered walls

The two hole system is a much more reliable method to insure the wall is filled. This allows the excess air to get out and you can tell when the cavity between the joists is full.

Using one hole at the top, you have no idea how much is in the cavity. You can blow it in at the top and have it get hung up on some wiring, lathe or any obstruction. There is no way for the air to exit. This will cause a bridge and the insulation may not get to the bottom.


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