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My house has two different kinds of foundation, The older part is brick-over-fieldstone. The newer part, dug a bit deeper, is poured concrete.

When that extension was added, they added a cinder-block (and dome poured concrete?) bulkhead to support what was retained of the old back wall, seen below with some cabinets sitting on top of it:

view of bulkhead from new basement

As you can see in the next picture, they retained most of the original (loadbearing) foundation wall, just bracing the lower portion. (The wall behind the cabinets is brick; the opening for pipes is looking at the back of thr right-hand cabinet.)

View of how back of bulkhead merges into old foundation

M question is at the far end of the bulkhead where it meets the new poured-concrete foundation wall. Apparently these were construcred as separate units, and there's a thin gap between them:

View of where bulkhead meets wall

And the bottom of this crack (sorry, no pic) is my main water infiltration points, when the ground-water level gets high enough. (The major floods in 2010, for example.)

So: What's the right way to seal this? Just try to stuff hydraulic cement into the crack? Caulking? Expanding foam? Something else?

Or would that endanger the brick foundation behind it? (Note that I've never seen any sign of leakage there, so I suspect the additional foot or two of depth in the new section is what puts it below the high-water line.)

  • If the basement floor is below the waterline, there's really nothing that you can do short of a perimeter drain and a sump pump...but even then, I'd hesitate to finish any part of a basement that is below a water line. – DA01 Nov 23 '15 at 16:23
  • Not planning on finishing it per se (it's workshop space) though I may want to insulate it and insulation must be covered. It leaks rarely (3 times in 7 years and one was a hundred-rear flood), but I'd rather keep wster away from the tools and such if/when it rises again. I have a pump to catch anything that does come in, but currently the water's just running across the floor when it happens. I'm not sure whether opening the floor for a french drain would be a good idea... My other leakage point is the prefab bulkhead-door enclosure and the door therefrom. – keshlam Nov 23 '15 at 16:35
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It's a huge undertaking, but the only way to manage water from entering the basement walls is from the exterior. Excavating along the wall to the foundation, applying a petroleum-based sealant to the wall, silt fabric, stone base, perforated drain pipe, more fabric and stone. Backfill with a grade away from the house. I've heard of perimeter drain channels working very well to control water entering basements. This usually entails installing a sump pump as well. I don't put much faith on cement paints (Dryloc) and grouting or plugging the openings from the inside just diverts the water to a different place.

  • my worry on perimeter dtains is whether the openin needed for them would increase my risk if the pump failed... plus their being a hassle, thougn less so than the exterior redo. – keshlam Nov 23 '15 at 16:41
  • And I'm a bit paranoid about disturbing the 100-year-old brick section. – keshlam Nov 23 '15 at 16:43
  • consider installing the interior drains only near the poured walls. The drain channels I've seen are 2 inches wide x however long you want them. This is the best way to manage water penetration especially if you are planning to finish (or semi-finish) your basement. – ojait Nov 23 '15 at 16:48
  • That's roughly what I'd been pondering... So quextion is whether to rent a concrete saw that can get sufficiently close to the wall and try to DIY, or hire someone to make thst cut, right? – keshlam Nov 23 '15 at 18:36
  • Or find a drain contractor who isn't opposed to you doing some of the grunt work while he tends to the details. – ojait Nov 23 '15 at 21:38
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There are various products that will seal a concrete crack for you. In particular there are expanding polyurethane foams intended to seal basement cracks against leaks.

Here are two companies that sell a variety of products: http://www.appliedtechnologies.com/home/concrete_crack_repair_methods.html http://www.radonseal.com/crack-injection/diy-injection.htm

How well this will work in your case will depend on the situation.
Yes it is typical that basements with pre-cast bulkheads will leak, because the builder often does a poor job of sealing the joint, the bulkhead may shift slightly after initial attachment, and the backfill of the overhang is often not compacted sufficiently, so the soil slumps and offers a easy path for ground water to run in.

If the water is only excess on that side, you can keep it out there with one of these products. But as ojait hints at, if the water table is higher than your slab, it will find a way into the basement some way. Worse case treatment are the perimeter drains and a sump pump as he indicates.

In my basement, I've had all these problems. I've minimized the recent problems by installing french drains leading away from all the downspouts. I still get leakage around my bulkhead, and I will use one of these caulks to stop that. I have had times in the past, usually the first hard long rain in the spring, where water came up all around my basement slab. Only a working sump pump dealt with those situations.

My ultimate fix is to dig in an exterior drain pipe from the basement footings to daylight down hill. Then I'll put a plastic membrane down and finish the floor.

  • Since I only have the crack and the bulkhead leaking as far as I know, this looks like the place to start. If other leaks turn up, I'll look at adding the interior drains to my existing pump. And I'm working on the exterior grading, though french drains would have the problem of where to drain to. (Yes, I know, sump/leachfield, but as I say under normal conditions I think sealing will do the job and under abnormal conditions that won't dispose of much.) Thanks for the pointers. – keshlam Nov 24 '15 at 17:07
  • For what it's worth: These systems appear wel-designed to deal with ctacks in concrete. Unfortunalely, even the poly version (designed to exoand into place when it hits moisture) really doesn't seem to deal well with cinderblocks that have cupped ends. I think I may be better off using one of the spray-foam polys to fill that large a gap, behind a hydraulic-cement capture wall... – keshlam Dec 8 '15 at 2:49

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