# What to do about hole in slab foundation behind bathtub?



## oh'mike (Sep 18, 2009)

Can you pour a slush coat of concrete?


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## Robpo (Mar 30, 2014)

Usually there is insulation wrapped around pipe where it comes through concrete. I am not sure of the purpose. If you are going to pour concrete it might be a good idea to put some around pipe or fill the hole with Great Stuff or something similar.


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## iLikeDirt (Apr 27, 2014)

I can pour in some concrete. I just want to know if that's the right solution. Termites can squeeze through tiny tiny holes… would the new concrete bond with the existing slab in a manner that termites won't be able to get through?

The pipes are uninsulated. Since they go underground I suspect there would be no point.


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## Bud Cline (Mar 12, 2006)

iLikeDirt said:


> I can pour in some concrete. I just want to know if that's the right solution. Termites can squeeze through tiny tiny holes… would the new concrete bond with the existing slab in a manner that termites won't be able to get through?
> 
> The pipes are uninsulated. Since they go underground I suspect there would be no point.


That "block-out" is common. Some get closed up a little tighter than yours - some don't.

I wouldn't pour concrete tightly against any of the pipes. Treat it and leave it is what I would do for now. Then in another ten years you can...........


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## r0ckstarr (Jan 8, 2013)

Bud Cline said:


> That "block-out" is common.


What is the reason for it? Mine is the same way. I was also told that it was normal.


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## oh'mike (Sep 18, 2009)

The slush coat is fairly thin and is used to keep vermin out of the house--

I saw a picture of a tub that was packed with dirt from some digging little rodent---wrap the pipes with tape to keep them from abrading as they pass through the thin slab.


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## de-nagorg (Feb 23, 2014)

r0ckstarr said:


> What is the reason for it? Mine is the same way. I was also told that it was normal.


I would think that it is left this way so it can be replaced in the future when the pipes wear out.

And this is a guess on my part. 


ED


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## Bud Cline (Mar 12, 2006)

It is done so-as to allow some tolerance and flexibility for the plumbing process that follows the slab pour.


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## Seattle2k (Mar 26, 2012)

Just shoot Great Stuff in there.


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## Bud Cline (Mar 12, 2006)

Seattle2k said:


> Just shoot Great Stuff in there.


Hey...There ya go! Never seen it done, never even heard of it, but it may be the best idea yet. Just be sure to wrap all the pipes before you do because Great Stuff will ruin everything it touches.


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## ct18 (Sep 20, 2012)

Its done that way to make final connection when tub gets set. It is also because most of the time that trap is not a glue trap and needs to be accessible.


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## iLikeDirt (Apr 27, 2014)

The trap is buried below grade, annoyingly enough. Great stuff is a cool idea. I imagine that termites can probably eat through it, so maybe another termite treatment is in order first.


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