I have found two small holes in the foundation, near the floor, in the cellar. Water trickles in through these two holes. I am thinking of plugging them up with spray foam. Are there any possible downsides to this plan?

If plugging up these two holes turns out to trigger some other problem -- can the foam be easily removed, so as to restore the flow through those two holes?


Those two holes are relieving hydraulic pressure and draining the soil outside. If you plug them, the pressure may build up and you could have water coming in somewhere else.

Is the water coming in now going into a sump? Is it wetting the floor and causing high humidity in the "cellar"? It sounds like you might need a French drain outside the foundation to lower the water table around the foundation. But with the current situation maybe you could just fit flexible plastic hoses into the holes and conduct the water to the sump or to a drain.

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    I don't think I can put in a French drain around the outside because the neighbor's fence is pretty close to this house, and I think that would make it unsafe to dig a deep enough trench. (My impression is that a French drain would have to be dug a little bit deeper than the depth of the cellar.) – aparente001 Dec 28 '18 at 20:17
  • I had to mention a French drain because they are considered a standard solution, but since you already have these holes and that is the only place you have water coming in I would just keep them open and efficiently drain the water away. The original question was should you plug the holes and I have answered that I think you should not. The interference of your neighbor's fence means that you can reject the French drains as not applicable to your situation. – Jim Stewart Dec 29 '18 at 0:09
  • How much water per day comes in through those holes? If it is a small amount that would mean that possibly the water in the soil is mostly drained away outside the cellar. Maybe plugging the holes would have a negligible effect on the hydraulic pressure and you could do it with no effect. – Jim Stewart Dec 29 '18 at 0:20
  • Maybe I could plug them temporarily -- for one week -- to allow me time to fill a gap in the flooring in the path of the water, and let the mortar cure -- and then reopen the holes? Also, how will I know if plugging those little holes is detrimental? – aparente001 Dec 29 '18 at 3:54
  • AFIK you can plug it and see what happens. Disclaimer: My knowledge of basements and "cellars" is limited to what I have gleaned from decades of TV watching "This Old House" and "Holmes on Homes". – Jim Stewart Dec 29 '18 at 12:10

If you don’t have weeping tile to take the water away, the water is just building up on the outside and taking the path of least resistance. If you patch the holes it may just take another path into your basement if it can’t drain away on the outside. If your basement wall is poured concrete the holes may be from deteriorating cork over the years left in from the form ties and not parged properly. If you decide to patch, the water may drain away naturally or find a new way into your basement. Use expanding foam (easily removed) or hydraulic cement for a permanent fix. Good luck!

  • This is intriguing. I would like to understand these terms: cork, form ties, parge. – aparente001 Dec 30 '18 at 5:55

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