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I am trying to mitigate my basement flooding. The flooding is pretty minimal. Just in two location water seeps through the floor. One spot is in the back corner of the house and the other is along the back wall toward the middle of the house. The flooding is pretty minimal just about 1-2 inches of water probably 3-4 feet size puddle. There is a concrete pad directly behind this wall outside so I’m not sure how to divert the water other than installing a sump pump.

andrew richardson
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    Have you done the easy solutions yet? Grading, directing downspouts away from the house? – Huesmann Oct 24 '23 at 22:03
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    Are your gutters clean and emptying away from the house? It actually makes a huge difference and is cheap and easy to address. for a borderline problem, it might just be all the fix needed. – dandavis Oct 24 '23 at 22:32
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    how old is the house? 1920 house with no footings and no perimeter drain? what is your basement slab like? 1/2" thick with no drain rock / no vapor barrier / no insulation? what climate zone are you in (rainy, snowy, desert)? What is your soil type / bedrock, clay, sand, dirt? – Fresh Codemonger Oct 24 '23 at 22:41
  • Hmm. The best way? Jack the whole foundation (with house) up about 12 feet and fill around it? Pick the house up with a helicopter and set it down in a dry spot? Grab a tunnel boring machine and bore out a tunnel to someplace lower for the water to drain away? Or were you interested in practical solutions, rather than best solutions? The slope of the concrete pad outside could be corrected if wrong by "mudjacking" for instance. – Ecnerwal Oct 25 '23 at 00:31
  • What does your existing drainage system look like? If the water is coming from your roof, then you probably need to repair your drainage. If the water is coming from elsewhere, you probably have a grading issue. – JimmyJames Oct 25 '23 at 16:00
  • @Ecnerwal I believe that a practical solution would necessarily be better than an impractical one. – Tim Sparkles Oct 25 '23 at 17:57
  • Can you not 'tank' the basement, meaning broadly to install a waterproof lining? – Robbie Goodwin Oct 25 '23 at 21:18

3 Answers3

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The ideal solution is to waterproof the foundation and that's best done during construction.

Since it's too late for that, your next best option is to waterproof after the fact. This is best done from the outside, involves excavation & back filling and can usually be quite expensive. Even when it's done, there's no guarantee that it'll stop all water ingress, especially since it won't waterproof under the floor.

A French Drain around the inside wall of the foundation (local code permitting), draining into a sump pit which is then emptied by a sump pump is the bog standard way of dealing with water that gets into a basement. Unless you have a specific aversion to sump pumps (which wasn't specified in the question) this is probably your most cost effective way of solving the issue.

FreeMan
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    Actually it is just some hard labor DIY (saves a lot of $$$), no special skills needed – asinine Oct 24 '23 at 22:31
  • agree interior perimeter drain into a sump pit with a pump directed to storm water output is likely the easiest especially if the basement slab is crap enough to have 2" puddles but depends on so many things. – Fresh Codemonger Oct 24 '23 at 22:45
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    Please let me know, @asinine, where I indicated special skills were needed? Even if DIYed, excavating and sealing the foundation can be expensive, no? – FreeMan Oct 24 '23 at 22:53
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    French drains around structures with foundations are explicitly forbidden in my locality due to the fact that they often make things worse. – JimmyJames Oct 25 '23 at 16:00
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    Interesting, @JimmyJames. I've updated to reflect that. – FreeMan Oct 25 '23 at 16:09
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    Actually, you can't have any perforated pipe unless it is above the solid drainpipe. I live in a high-precipitation area so these rules might not be important everywhere, but I think that also means there's a lot of experience with how things can go wrong. When I disconnected my old porous ceramic drain-tile, the patio next to the house dropped maybe 1/8 to a 1/4 of an inch. – JimmyJames Oct 25 '23 at 16:45
  • Haha, bog standard. :) – screwtop Oct 25 '23 at 22:31
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In general, the problem is nearly always outside, and quite often it is simple to correct.

The next time there is a heavy rain, put on your raincoat and hat and walk around the house:

  • Are any gutters overflowing?
    If so, something is clogged or the gutters aren't sloping toward the downspouts.
  • Is the water from the downspouts flowing far away from the foundation?
    If it isn't, the horizontal pipes need to be extended.
  • Are pools of water forming near the foundation?
    If so, the land isn't sloping away from the house and needs to be landscaped.
  • Is there paving that runs right up to the foundation?
    If so, seal the gap and make sure the paving slopes away from the foundation.

All of these problems are easy to detect and relatively easy to correct.

After that, if there is still infiltration, examine in more detail to find where the water is getting in and where it is coming from, and then make appropriate corrections.

If the problem remains but isn't serious, you could have a sump and pump installed, but that's treating the symptom rather than the cause.

After all that, then it's time to call in the professionals and pay the big money.

In your specific case, you say "There is a concrete pad directly behind this wall outside".

I suspect that the pad was laid level rather than sloping away from the house. That's easy to check, especially when it's raining (or flood it with a hose).

If that's the cause, it needs to be either removed or tipped slightly, and depending upon what this particular pad actually is, that could be anywhere from a few hours of your time, to hiring professionals with heavy equipment.

Ray Butterworth
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  • "Is the water from the downspouts flowing far away from the foundation? If it isn't, the horizontal pipes need to be extended." That assumes the downspouts are going to the surface. A lot of old homes have downspouts that drain into a porous clay pipe that is nestled up against the foundation. The sign that's not working is that they overflow where the downspouts enter when there is heavy rain. – JimmyJames Oct 25 '23 at 19:42
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If one cannot easily landscape a slope away from the house (my flat has a tiny basement patio with house and walls all around it), digging and installed a drainage channel around the house is a good solution. That way less of the water is going to go up against and underneath the house and instead down the drain.

Also widen existing drains so that there is less of a chance that leaves and or rubbish can block them. Also a cheap leaf guard and sweeping the patio regularly will help that.

atreeon
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