Seal PVC Pipe Through Concrete

[Joseph Skoler]

I cut a 10" diameter hole in my foundation wall to slide an 8" PVC pipe to be used as a sleeve to hold a 6" PVC sewage drain pipe.

I need to seal (water-tight) between the concrete and the 8" PVC sleeve, and between the sleeve and the 6" PVC pipe.

I've seen recommendation for expanding foam and polyurethane sealer, as well as hydaulic cement and other solutions.

Unfortunately, the pipes are already run and only after spray foaming the basement walls and around the pipes did I find out that water is seeping in.

So I cut out all the foam on the inside and dug up the pipe on the outside.

Can I just use a product like Sika 1A poly sealer?

What would all your much more experienced people do?

Thank you!

 

[Tughillrzr]

http://www.flexicraft.com/PipeSeals/Main/

Ive seen geo guys use this type. second option is probably more cost effective and readily available.

Hydraulic cement and tar it. Make sure dry before backfilling. You can foam it to a certain point.

 

[Sponsor]

 

[Michael Young]

I cut a 10" diameter hole in my foundation wall to slide an 8" PVC pipe to be used as a sleeve to hold a 6" PVC sewage drain pipe.

I need to seal (water-tight) between the concrete and the 8" PVC sleeve, and between the sleeve and the 6" PVC pipe.

I've seen recommendation for expanding foam and polyurethane sealer, as well as hydaulic cement and other solutions.

Unfortunately, the pipes are already run and only after spray foaming the basement walls and around the pipes did I find out that water is seeping in.

So I cut out all the foam on the inside and dug up the pipe on the outside.

Can I just use a product like Sika 1A poly sealer?

What would all your much more experienced people do?

Thank you!

In my area we are not allowed to use spray foam. The inspectors want to see silicone. We usually fill the void with spray foam and then we use silicone to make the seal. Lots of silicone. probably one and half tubes for a hole that large.

 

[Joseph Skoler]

Here are some pics from inside and out.

As you can see, it is difficult to get to the 6" pipe from the outside and near impossible to get to the 8" pipe from the outside. Inside is fine.

 

[Joseph Skoler]

Maybe I should just dig out under the sleeve and fill the entire outside with concrete -- surrounding the sleeve and pipe?

 

[wwhitney]

In a retrofit situation (how long ago was the foundation installed?), I don't think that using a sleeve is required or useful.

When casting new concrete, you can use an oversized sleeve as a block out for the penetration. While the concrete may shrink around the sleeve and compress it, that's OK and ensures a seal of concrete to sleeve; then you just need to seal the annular space between sleeve and pipe.

But for a retrofit, your concrete should be done shrinking, so there's no issue. You've bored a 10" hole for a 6" pipe; you just need to seal the annular space between the pipe and the concrete; splitting that annular space in two with a sleeve just complicates things, and I don't see the upside.

Cheers, Wayne

 

[Joseph Skoler]

In a retrofit situation (how long ago was the foundation installed?), I don't think that using a sleeve is required or useful.

When casting new concrete, you can use an oversized sleeve as a block out for the penetration. While the concrete may shrink around the sleeve and compress it, that's OK and ensures a seal of concrete to sleeve; then you just need to seal the annular space between sleeve and pipe.

But for a retrofit, your concrete should be done shrinking, so there's no issue. You've bored a 10" hole for a 6" pipe; you just need to seal the annular space between the pipe and the concrete; splitting that annular space in two with a sleeve just complicates things, and I don't see the upside.

Cheers, Wayne

thank you so much for the background and explanation for sleeves.

the foundation is quite old but the sleev snd pipe are new.

given that they are in place and connected, what would be my best course of action?

Thank you.

 

[wwhitney]

Not sure of the best course of action, so I'm guessing a bit here, but I think I'd remove the 8" sleeve. Then you just have one annular space to fill.

On the exterior face, I would think a cementitious surface against the backfill would be a good way to go, possibly painted with some damp proofing if you have access from the outside. So you could pack the annular void with a non-shrink product like hydraulic cement, or something similar with a greater working time might be easier for you.

Ideally a non-shrink or slightly expansive cementitious product would provide an adequate seal against ground water, and you could fill the whole depth of the wall with one material. I'm not sure that's true in practice (no direct experience). In which case you could leave some interior depth unfilled with the cementitious product and use something else for the sealing. That could be a closed cell foam intended for the use, a silicone, or something else. If you have a nice smooth hole in a monolithic foundation to seal against, that Flexicraft product looks very nice if pricey. I think you'd need PS475 and leave 5" of wall depth of seal against.

Cheers, Wayne

 

[Breplum]

As a professional, the only way we deal with these penetrations is product like Tughill posted.
Supply houses sometimes have favorable relations with one brand or another, but they all work the same.
You provide your O.D. and your I.D. they make the specific customized band and ship it to you. You assemble, tighten: DONE or as they say "as easy as 1-2-3" http://www.flexicraft.com/PipeSeals/
In your case, I might see what can be cleaned up, but I might also remove the pipe and core a clean hole to possibly match the common ready-made flex seals.

 

[Joseph Skoler]

Access to the face of the outside wall is not possible.

I think I'll dig under and back as much as possible and fill it with concrete.

Then fill from inside the basement, around the sleeve and between the sleeve and pipe, with as much silicone as possible, as far into the hole as possible.

Thanks everyone.

 

[Reach4]

I think I'll dig under and back as much as possible and fill it with concrete.

Not fence post concrete. Use hydraulic cement if trying to seal something with concrete.

 

[Joseph Skoler]

Not fence post concrete. Use hydraulic cement if trying to seal something with concrete.

My understanding is the hydraulic cement sets very quickly. I don't want that because I will be filling a large hole in the ground under, around and over the sleeve and pipe.

Is my understand correct?

Thanks!

 

[Reach4]

As you are searching cure times, note that regular concrete shrinks as it cures. Hydraulic cement does not. So if you are trying to seal the 8-inch pipe against the outside foundation with concrete, something that shrinks does not seem like a good idea.

 

[Joseph Skoler]

Great point.

So what I'm looking for is something that can be poured well to get down into every spot and does not shrink.

Sakrete has a non-shrinking grout that looks good but the datasheet says not to pour it thicker than 4". I think I'll need at least 12" thick (probably 15").

Any suggestions?

 

[wwhitney]

Can you clarify/annotate your last photo? It sounds/looks like you have two different conditions for your penetration across the depth of your foundation wall. On the inner side, a bored hole, and on the outer side, a larger foundation void you need to fill.

If that's the case, it would seem to me that you need to treat each condition separately. Where you have a bored hole, remove the sleeve as it interferes with filling the annular void. [Not clear to me what is outside and inside the void, but it ought to be possible to slide the sleeve out of the foundation and then cut it off your pipe.]

On the outer side, if you don't need to seal the foundation to the pipe, because you have adequate depth and capability of sealing on the inside portion, you can just wrap the pipe with the usual foam for concrete penetrations, and fill your void with concrete. But if you need to seal the pipe to the foundation on the outside as well, I don't believe the foam wrap allows that, and you'd need to use a sleeve for concrete placement, then seal the annular void, just as on the inside.

Cheers, Wayne

 

[Reach4]

I have the impression that outside seals are better than inside seals, because pressure is working to improve the seal, vs outside pressure is trying to blow out a seal.

 

[Joseph Skoler]

Here are a bunch of pictures showing the progression of the coring-sleeving-piping. I hope it helps make clear what I'm doing.

 

[WorthFlorida]

I'm in my brand new house 1981 in Algonquin Il. Our first thunderstorm I had water pouring in from the foundation wall like a garden hose was fully open. There was a gap between the 3/4" copper water line and the 4" PVC waste line through the poured concrete foundation wall. The next day I stuffed the opening from the inside as much as possible with hydraulic cement. It was about 1" round. It never leaked there after. BTW, hydraulic cement expands when drying and it doesn't set that fast. You'll have plenty of time to work it in.

 

[wwhitney]

So how long is your 8" sleeve? Looks like it passes through the foundation then through some backfill, then under your porch footing, making it a few feet long?

Also, it looks like the outside of the foundation is rubblestone. Is the inside as well, or is there a poured concrete wall/bench against the rubblestone?

Since your sleeve is so long and partially buried, scratch my suggestion of removing it. I think at the outer end the best you can do is fill the annular space between pipe and sleeve, which will require a bit more excavation to expose the full sleeve. No opinion on silicone vs closed cell foam; I don't think hydraulic cement makes sense for sealing plastic to plastic. Don't place concrete directly against the 6" pipe. You could wrap the pipe with foam and then fill the hole with concrete, but I don't see what that buys you over just backfilling the hole.

Then at the inner face, you need two separate seals, pipe to sleeve and sleeve to foundation. For the latter, hydraulic cement makes sense to me.

Cheers, Wayne

 

[Gsmith22]

what Tughillrzt posted with the seal that you tighten around the pipe is really the perfect way to do what you are doing and would be fail safe. But a pretty good second best way is the hydraulic cement. Don't let the idea of a perfect plan (the seal you tighten around the pipe) get in the way of implementing a really good plan (the hydraulic cement). you just pack the hydraulic cement it in the annular space (from inside if that is your only access) and as everybody else has noted, it expands as it cures stopping any "leak" along the cold joint between it, the previously cast concrete, and your pipe. If you want to really go nuts, get some bentonite clay and fill the area around the pipe at the outside. It comes in bags that you add water to and once it hydrates, there is no water getting through it. Its commonly used to seal wells and prevent water movement underground.

Hydraulic cement is commonly used by pool builders to seal any leaks in in-ground concrete pool shells prior to applying plaster finish. They only have access to the interior face (shotcrete or gunite pneumatically applied to "dirt form" to create shell) so the hydraulic cement is applied at the interior to stop water from migrating from the ground into the pool so that the plaster finish can be applied. I know it works because it was done to my pool at what I thought would be non-sealable leaks and I was pretty shocked at how effective it was at stopping water coming into the empty pool shell so the plaster could be done.