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Seepage around sewer pipe at foundation

Posted by mary_228 (My Page) on
Sun, Sep 14, 08 at 11:03

During heavy storms we are getting water seeping in around the sewer pipe where it exits the house through the foundation. How is something like this repaired?

We first experienced this problem shortly after moving into this new house (1992) when I was (over) watering the foundation plantings. We ignored it and (naturally) right after we finished the basement and had a heavy storm, it happened again. My husband dug out the ruined concrete and wrapped oakum around the pipe. He mixed new concrete and waterproofed the area.

Unfortunately, the area must have degraded again. We can see cracks through the waterproofing paint and quite a bit of water came in again. What sort of contractor should we hire and what process will they use to repair this? Any idea of cost?


Follow-Up Postings:

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RE: Seepage around sewer pipe at foundation

you can't use regular concrete, as it actually shrinks as it cures and opens the gaps back up. use hydraulic cement, it expands as it cures and seals tight. mix it ONLY when you are ready to apply it, as it hardens quickly.


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RE: Seepage around sewer pipe at foundation

Thanks, Davidandkasie, my husband did use hydroment (I think that what he told me).

I wonder if the repair needs to be made from the outside? And what type of contractor should I contact?


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RE: Seepage around sewer pipe at foundation

yes, it really should be done from outside. you want to stop it BEFORE it gets in the wall.


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RE: Seepage around sewer pipe at foundation

I'm looking at about five feet below the surface of the ground to get at that pipe (based on the height of the pipe from the basement floor. A plumber I contacted is going to take a look from the inside at the cleanout and see if the pipe itself looks ok. He told me this is a common problem and that one they repaired recently (at a similar depth) cost $2000!

Is this the right approach to take?


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RE: Seepage around sewer pipe at foundation

yes, you stops leaks from teh outside. if you try to stop it from tehinside, teh water will just travel in teh wall and find another spot to come thru. if you cannot afford to pay someone to do it, grab a couple shovels and get to digging. or pay some local teens 30-40.00 each to dig the hole for you.


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RE: Seepage around sewer pipe at foundation

I only see two problems with the aforementioned solution to this problem. Not only is it PROHIBITED BY CODE in all likelihood it will make the problem worse rather than correct it.

The Plumbing Codes dictate that whenever any pipe is run under or through a footer or footer wall the pipe MUST BE sleeved and there is to be no direct contact between any pipe and masonry materials. To create a sleeve we must first select a short section of pipe at least two nominal trade sizes larger than the desired pipe and long enough to extend through the wall with 2 to 3" extending out on either side. The sleeve pipe may be cast into the concrete, mortared in when the wall is laid or you may make a hole and install it after the wall is constructed. The sleeve may be sealed to the wall by means of pitch, tar, expansion foam or any other locally approved suitable means.

Once the sleeve is in place the desired pipe is to be passed through the sleeve and the space between the outer wall of the desired pipe and the inner wall of the sleeve is to be filled with expansion foam.

The purpose of the sleeve is twofold.
1. Pipe has a much greater coefficient of linear thermal expansion than does concrete, cement or other masonry materials. Whenever pipe is in direct contact with masonry materials as the pipe expands or contracts it rubs against the masonry material having the same end effect as repeatedly rubbing the pipe with an abrasive grinder.
2. If a metal pipe is in direct contact with any form of cement, mortar or other masonry materials the lime in the mortar reacts with the metal in the pipe and causes severe corrosion of the pipe wall.

Not only will cement or even hydraulic cement not effect a water tight seal, digging on the outside of the wall will most likely make the problem even worse. No doubt, by now the soil on the exterior of your basement wall settled to a point were it has achieved maximum compaction. If you were to dig up that soil, attempt a repair from the outside, then backfill the hole, the soil immediately around the problem would be loose and would offer very little resistance to surface water soaking down to the pipe.

No doubt it would be very difficult to install a sleeve at this point however you can do the next best thing. Working from the inside clean out as much dirt and debris as possible to enlarge the hole around the pipe, then using a can of expansion foam that has a flexible tube on the nozzle, insert the tube as deep in the hole as possible and fill the hole with as much foam as you can get in, then continue spraying the foam as you pull the tube out. The foam will adhere to both the masonry material and the pipe wall; yet still provide a flexible material that will compensate for the thermal expansion or contraction of the pipe.


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RE: Seepage around sewer pipe at foundation

lazypup: Thanks for your comments. I took a close look and there is definitely a sleeve through which the sewer pipe travels, sealed with expansion foam, so I don't think that's the issue.

I found some photos of the pipe and immediate area prior to repair. Maybe these will help in the diagnosis of the problem.

Here is a link that might be useful: Basement Pipe photos


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RE: Seepage around sewer pipe at foundation

Do the repair from the interior. Spending any money with a contractor on this is a waste.
Drill out a uniform width around the pipe. Keep the walls parallel to the pipe. When you're ready to install the hydraulic cement be aware that it sets up in about a minute. You want to mix it up in batches of about 1/4 of the circumfrance of the pipe and continually mix and force it into the crevice as quickly as possible. The idea is to get as close to one continuous mass in there as possible. Have at least 4 disposable containers at hand so you don't waste time cleaning out the containers, just the tools.
The repair, if done correctly, should last 8-10 years.
Ron Thompson
Thompson Carpentry Corp.


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RE: Seepage around sewer pipe at foundation

Ron:
What do you think is causing this problem? The repair my husband made (using Oakum and Hydroment) only lasted 6 years. So there must be a crack (or more) on the outside allowing this moisture to degrade the foundation, right? To keep fixing the inside is like putting your finger in the dike, isn't it?


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RE: Seepage around sewer pipe at foundation

Last Sunday, 9-14, we returned home after a long weekend and found exactly the same problem, seepage around the sewer pipe and a pinhole about a foot off the ground spraying water. After trying to mop the water and catch it in a bucket, which didn't work, I went outside and fastened a piece of plastic over the flower bed so water was forced to run into the grass. By the time I got downstairs again all the seepage and leaking had stopped.

The permanent fix will be to raise the soil in the flowerbed so water can't sit there but has to run off.

We had 43 hours of rain, 6-10 inches, very unusual for southwest Michigan.


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RE: Seepage around sewer pipe at foundation

hendricus: We had the same storm system you experienced. It was the heaviest rainfall in a 24 hr period ever recorded for our area. As for your receommendation, we have a landscape architect coming for another project, so I will ask her about the slope. Looking at the plat of survery, the corner of the house where I'm having the problem is at 778.8 ( I'm pretty sure this is the top of the foundation) and the curb at the street is 778.72 so i don't have much to play with.

What I am really concerned about is the degradation of the concrete wall. It doesn't seem right that my husband was able to pull out that much of the concrete out around the pipe. IOW, water infiltration must be occurring not only during these heavy rains. So is the foundation seriously damaged? What type of contractor would assess this?


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RE: Seepage around sewer pipe at foundation

I wouldn't worry too much about the foundation itself. Any time you put a hole in the wall it becomes a weak point, but the rest of the wall should be just fine. Any repair should be from the outside so when water and soil push against it it just gets tighter in the hole. I would look in the yellow pages for a plumbing company that is licensed to hookup to city sewer, they would be familiar with this type of work.


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