The proper way to seal any kind of water leakage in a concrete wall is from the outside. That is not always practical, as in this case. This question is about alternatives to solve the problem, and alternatives do exist. Solutions such as interior surface coatings, and apparently hydraulic cement, are not effective. However, some other solutions are available, and I'll mention a couple that I know about below.
About a year ago, I posted the question How to seal a pipe pass-through in a basement wall. The gist of that question was two pipes passing through a poured concrete foundation wall (one an iron sleeve, one a PVC sleeve). Foam had been used to seal the gaps between the sleeves and the wall. After 15 years, ground water had started to leak in around the sleeves.
My fix included hydraulic cement (recommended on how-to sites as the proper solution). However, the hydraulic cement appears to be water permeable. So I'm back for phase 2.
The typical contractor solution at construction is to fill around the pipes with spray foam. The foam is not rated as water submersible or even waterproof (probably why the old foam failed), so replacing it wasn't a solution. I ended up cleaning out all the old foam, cleaning and sealing the surface of the iron sleeve with neoprene-based adhesive, and then packing the voids with hydraulic cement. The cement has adhered well, but after 10 months, water is seeping through it. Apparently, the stuff is porous.
A picture of the current condition (click on it for a larger image):
Below the iron sleeve on the right (the original issue), the hydraulic cement is darker from the moisture and you can see some efflorescence. The bigger problem is the PVC pipe on the left, which I didn't think would be a problem to seal. The hydraulic cement around that pipe is visibly wet, and enough water gets through to drip.
- This can't be sealed from outside. The exterior of that wall is not accessible without significant destruction and reconstruction, which would be cost-prohibitive.
- The walls are 8" thick poured concrete, so common solutions for tapping cinderblock walls aren't applicable.
- Relieving the water pressure from the inside may not be practical (busting up the basement floor, tunneling under the footer, and creating a drain channel to an existing sump pump). The house is located next to a community water catchment field, so the water table is high. A sump pump would need to drain ground water from several acres to stay ahead of the water table, and the discharge goes back into that same field.
So this is a candidate for an alternate solution designed for when an exterior fix isn't practical.
I am aware of several possible solutions:
Injecting sealant into the wall: This is commonly used for structural cracks and leakage problems. Epoxy is injected into cracks for structural repairs, Polyurethane is injected into cracks and pipe pass-throughs to seal water leaks. These are injected the full depth of the wall and are supposedly stronger than the concrete, itself.
In my case, I would need to break up the hydraulic cement and then seal the gaps with an injected polyurethane system (professionally done high-pressure injection or a DIY kit like this; short video of the DIY process here). There are a few brands of such DIY kits. The kits aren't cheap ($100 for each pass-through), and professional injection is several times that cost.
Control and direct the water flow rather than trying to seal it out: This is commonly done with cinderblock walls. The cores are tapped so water has an easy path to a collection system and goes to a sump pump for discharge. Sometimes the interior walls are then lined with a waterproof membrane to control humidity.
In my case, the basic idea would be to drill a channel in the hydraulic cement directly below each pipe so water has an easy path to drain and is not under pressure. Connect these to tubing that runs down to a nearby floor drain.
Has anyone had experience with these (or other) solutions and can share how successful it was long term?