# Spray Foam in Existing Furred Walls?



## Nealtw (Jun 22, 2017)

You walls are cold and the moisture in the house is condensing on the walls.
You can warm the wall or insulate the walls or lower the moisture level in the house.

It takes a while for the cold to remove heat from a wall but once it has it will stay cold and get worse until the weather changes.
You just need to look at what they would do with a new build like that today in your area.
I think I would be looking at removing drywall and strapping and adding a thicker foam board.


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## joecaption (Nov 30, 2011)

It would be interesting to open that wall to see what you really have going on.
The bottom and top of the walls should have been fire blocked before sheet rocking.
May have been as simple as installing horizontal strips of strapping.
In your area there should be R-19 insulation in the walls, your no where near that.
With the sheet rock removed the block could be injected with foam, 
It would be best if at least 1" foam was added over the wall first then the strapping to stop thermal bridging, but that's going to throw off all your window and door trim.
With a home that old I'd be looking up in the attic and see how much is up there, in your area it should be about R-50 which is about 12".
Older single pane windows?
Rim joist insulated?
Any insulation under the floors?


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## user_12345a (Nov 23, 2014)

i wouldn't attempt getting foam sprayed in the gap, The foam expands as it cures which can wreck your plaster wall. 

insulate from the outside with foam and have stucco or siding put over it. 



or, remove the lath and plaster, build a 2x4 wall 2" away from the brick and put R19+ batts plus vapour barrier. That would be a major renovation through.

Either way, it won't be cheap at all. Wouldn't be surprised if you were looking at 20 grand to do it from the exterior and even more from the interior.

Do try controlling moisture with exhaust fans if u have them. Your humidity is probably well over 40%, 25-40% is the upper limit for a lot of houses in cold climates depending on weather and window quality.


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## dmartin1868 (Dec 30, 2017)

joecaption said:


> It would be interesting to open that wall to see what you really have going on.
> The bottom and top of the walls should have been fire blocked before sheet rocking.
> May have been as simple as installing horizontal strips of strapping.
> In your area there should be R-19 insulation in the walls, your no where near that.
> ...


I was thinking the same thing, open up the wall and see what's going on. I don't like the thought of all the work but as far as cost it's just drywall and insulation, I can handle the labor. 

As far as injecting the block with foam, there is an air gap between the cinder block and the outside brick, would you recommend filling that gap with foam as well? 
The windows are dbl pane.
What is Rim joist?
No insulation under the floors but the basement is finished and heated. 
Thanks for the help.


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## dmartin1868 (Dec 30, 2017)

user_12345a said:


> i wouldn't attempt getting foam sprayed in the gap, The foam expands as it cures which can wreck your plaster wall.
> 
> insulate from the outside with foam and have stucco or siding put over it.
> 
> ...


I cringe thinking of the first ideas you suggested...ouch! 
I have tried controlling moisture, it seems to be difficult, this is why I think the basement moisture issue we had repaired is a concern of mine, I really think the moisture is coming up from below and causing a portion of this issue. 
Again, I must re-iterate this point, we did not have this issue before we had the basement water problem fixed...??


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## dmartin1868 (Dec 30, 2017)

Nealtw said:


> You walls are cold and the moisture in the house is condensing on the walls.
> You can warm the wall or insulate the walls or lower the moisture level in the house.
> 
> It takes a while for the cold to remove heat from a wall but once it has it will stay cold and get worse until the weather changes.
> ...


I am in agreement with you and joecaption....your thinking makes the most sense to me. It also agrees with alot of the info I have read on the net and conversations I've had with other people in my workplace.

I'm not liking the idea of ripping my walls out though! :vs_worry:
I really want to know if injection of foam can be done through the walls and just patch holes? Why would foam injection ruin my walls, isn't there minimum expanding foam for this very reason?


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## Nealtw (Jun 22, 2017)

dmartin1868 said:


> I am in agreement with you and joecaption....your thinking makes the most sense to me. It also agrees with alot of the info I have read on the net and conversations I've had with other people in my workplace.
> 
> I'm not liking the idea of ripping my walls out though! :vs_worry:
> I really want to know if injection of foam can be done through the walls and just patch holes? Why would foam injection ruin my walls, isn't there minimum expanding foam for this very reason?


You can try, but I would think about what you do if it doesn't help. You move from an easy tear down to a real pain in the ass


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## user_12345a (Nov 23, 2014)

When you seal/tighten up the house, you raise the moisture level, which can result in condensation in areas that you didn't have it before.

The house is a system and what you do to one part can adversely affect other parts.

One problem covers up another. Like excess leakage covering for lack of insulation, you control the leakage and start getting condensation.


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