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-   -   Filling a cinderblock with sprayfoam? (

drewdin 01-21-2013 01:17 PM

Filling a cinderblock with sprayfoam?
I have some cinder block foundation peices that are broken, I can see the two hollow spaces in between them. Would it be ok to fill them up with spray foam? I was thinking that it would be fine but i wanted to check first.

Is there anything I should look out for or can I just go to town!

nealtw 01-21-2013 05:55 PM

Non- expanding foam?

drewdin 01-22-2013 07:05 AM

Thanks for the link, do they sell that at the box stores? I was going to use the DOW spray foam but I know it expands a ton. Maybe the window and door foam?

nealtw 01-22-2013 07:13 AM

Don't know, just found the that site.

drewdin 01-22-2013 07:45 AM

i didn't see anything when I searched other than that site. I guess as long as the top of the cinder block is open its OK, that way the foam has a place to expand. There are only a few spots and they are open ended.

nealtw 01-22-2013 08:22 AM

I would be worried about blowing them out. But if you are not going to do the whole wall, you would still want to build a wall inside and insulate that. I'm not sure you get much gain with just doing a few.

drewdin 01-22-2013 10:51 AM

I am just sealing cracks right now, I can see tiny areas where there is a space between the wood foundation and cinder block foundation.

One specific area on the right side I cant get in close enough to fill the gap as its the corner and there is a pipe there. I cant get around the pipe to get at the opening. My thought were to fill the center of the cinderblock and the overflow would fill the gap.

I do plan on adding a 2" foamboard to the wall, using liquid nails(Unless you recommend anything else) but thats is in the future.

I can supply some picture later if needed, thoughts?

Wuzzat? 01-22-2013 02:40 PM

Is the foam insulating value is greater than the insulating value of the dead air in the hollows? There is also air infiltration which the foam may help with, or just use caulking.

Even then it may not be worth it in energy savings over a 10 year period ('investment horizon').

drewdin 01-23-2013 06:53 AM

I tried the spray foam last night, i was unable to get it to stick as the crack was too high and it wouldn't bond to the concrete. Ill have to seal the gap with silicone from the outside as I know the location.

nealtw 01-23-2013 08:12 AM

Have a look at caulks made for concrete, they may be better than silicone.

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