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View Full Version : Sealing Cinder block to PVC



Master Brian
12-30-2008, 02:13 PM
Currently I have 4" cast iron pipe running from inside out the house. I am noticing a bit of a drip stain on the inside wall where the cast exits the wall, so I know the time is coming to replace this cast iron.

My question is if I take out the 4" cast and replace with 4" PVC what do I use to seal between my cinderblock basement wall and the earth. The plumbing exits about 3-4' below grade.

Gary Swart
12-30-2008, 02:25 PM
Before I answer your question, here's a couple of mine. What the heck is this 4" CI pipe for? And, do you really need a 4" pipe to do whatever it is that is does?:confused: OK, now to your question. I would use Water Plug or a similar product. This is a fast setting Portland Cement that will even cure underwater. You mix it and apply it immediately. Pack it into the space as tightly as you can. You have to work FAST as there is very little open time. Use gloves as this stuff has mega amounts of lime and will really burn your hands. Forget about silicone or caulking, you can still have a leak.

Master Brian
12-30-2008, 02:43 PM
Before I answer your question, here's a couple of mine. What the heck is this 4" CI pipe for? And, do you really need a 4" pipe to do whatever it is that is does?:confused:

It's my main sewer line out the house. Sorry!

Do I need 4"? It's what is there. I have about 10' of this cast iron left in the house, minus the 2nd floor and the vent stacks. The rest has been replaced with 4" PVC and there is a 4" PVC cleanout about 3'-4' outside my house where I would tie into. So, it would just make sense to replace with 4" pipe, vs, trying to reduce and the go back up.

Now another question, can this cement be done in stages? Reason I ask is, if I pack this from the outside, do I have time to pack again from the inside? Can it be installed into the tight space with a mortor bag or something?

kingsotall
12-30-2008, 05:04 PM
Might want to check if the pipe needs to be sleeved.

SewerRatz
12-30-2008, 05:23 PM
Sounds like your talking about an overhead sewer. Very often, the pipe breaking off at the wall just outside the foundation is the source if this leak. Here in Illinois you still have to run cast iron out the wall. Best thing to do is call your city plumbing inspector and ask them what they would require.

Gary Swart
12-30-2008, 06:07 PM
OK, you cleared up the picture for me:D I had it in my mind that you had a 4" pipe sticking out of the side of you house that was oozing water out. You have to stick with 4" since this is your sewer line, but you should have a professional determine where the leak is coming from and if you are looking at a repair or whole new sewer line. Sealing around the pipe is the simple and cheap part.

nhmaster
12-31-2008, 04:49 AM
The cast can be cut back and Fernco'd to PVC. In any case though you must sleeve the pipe where it runs through the foundation.

kingsotall
12-31-2008, 05:37 AM
NHMaster, for a 4" pipe we use a 6" piece of ABS. What's common to your areaż

hj
12-31-2008, 05:42 AM
are you sure it is the pipe and not the concrete that is leaking? Sleeving the pipe just gives you two places where you have to make a watertight connection. One around the sleeve and the other between the sleeve and the pipe. And using plastic just makes it harder because the sealer may not adhere to the plastic properly.

Master Brian
12-31-2008, 09:07 AM
I am not looking at sleeving the pipe or sealing the existing pipe. I am looking at completely removing the existing pipe and replacing. I'll check into what type needs to be run out of the house, I believe PVC is ok here, but I'll ask.

No, I'm not certain it is the pipe and not the concrete, but considering this pipe is about 95y/o, I think it's time to replace. Especially since it looks as if someone broke off a 1-1/2" Y that came off the line and seem to have filled it with something, possibly even spray foam. That doesn't appear to be the source of the leak, but again, when I replace this line, it will all be taken care off.

You mention sleeving the pipe, I said I'm not looking at doing that. Let me clarify, I am not doing anything to the existing pipe, except replacing it. It's almost 100y/o and the rest hasn't been in great condition. It's coming out and I'm running new pipe out the wall. IF that needs to be sleeved, that is one thing and I'll look into that.

Thanks for the help!

nhmaster
12-31-2008, 09:17 AM
305.2 Breakage. Pipes passing through or under walls shall be protected from breakage.

99k
12-31-2008, 09:58 AM
Sleeving is necessary to meet code ... it is obviously easier to seal w/out the sleeve but you are being instructed as to the proper protocol. In my area you would use hydraulic cement to seal the wall to the sleeve and then use foam backer rod to seal the ID of the sleeve to the OD of the PVC. This allows the pipe to move w/out a potential break ...

Master Brian
12-31-2008, 10:49 AM
Sleeving is necessary to meet code ... it is obviously easier to seal w/out the sleeve but you are being instructed as to the proper protocol. In my area you would use hydraulic cement to seal the wall to the sleeve and then use foam backer rod to seal the ID of the sleeve to the OD of the PVC. This allows the pipe to move w/out a potential break ...

That's what I need to know. I am not looking for a shortcut, I want this done correctly and I definately don't want a break to occur.

theplumber
12-31-2008, 10:57 AM
Not sure if this part is getting confused but it seems like it. When the others here are saying sleeving, they aren't talking about sleeving the inside of your old sewerline. The line itself is supposed to have a can or a sleeve on the outside of the sewerline for it to pass through when going through concrete.

Hope this helps.

nhmaster
12-31-2008, 03:51 PM
we usually use about a 3' piece of 6" pvc and 2- 6x4 fernco's. Run the 4" drain through the 6" and use the Fernco's to seal the ends off, then hydraulic cement the 6" around the foundation hole.

kingsotall
01-01-2009, 04:30 AM
That is an ingenious way to go about that NH.

Master Brian
01-01-2009, 06:06 PM
Not sure if this part is getting confused but it seems like it. When the others here are saying sleeving, they aren't talking about sleeving the inside of your old sewerline. The line itself is supposed to have a can or a sleeve on the outside of the sewerline for it to pass through when going through concrete.

Hope this helps.

I understood, but thanks for trying to clarify. It doesn't look like the old cast iron is sleeved, which may be why it is breaking/leaking.

Nhmaster, that is a great idea, thanks!! Just out of curiousity would it be a good idea or bad idea to fill the void between the 4" and 6" with foam spray or something or not? I'll use the 6x4 ferco as well.... Thanks for that idea, that seems very easy.

nhmaster
01-02-2009, 04:16 AM
I don't think foaming the space would make much difference either way. We do this on every single new house because the inspectors jumped all over this little code tidbit a couple years ago.

99k
01-02-2009, 05:58 AM
we usually use about a 3' piece of 6" pvc and 2- 6x4 fernco's. Run the 4" drain through the 6" and use the Fernco's to seal the ends off, then hydraulic cement the 6" around the foundation hole.

Hey NHmaster, that is a great idea!! Very simple and very robust seal and certainly better than backer rod.

burleymike
01-04-2009, 09:30 PM
Sika makes a product, Sika Swell. It is designed for sealing around penetrations where water is a problem.

I bought my house from a bank (forclosure). They had the water and sewer lines replaced at some point during the 2 years the house was on the market.

The plumber or whoever they hired ran ABS straight through the basement wall and 100' to the tank. I sure hope the pipe does not break. Funny though the water line is copper coming through the wall and PVC at the well so they did that one right.

I am glad they replaced the line, I found bits of what looks like orangburg where they backfilled the trench.