I'm facing a challenging situation with my house and need some advice. I'm new to this, so bear with me as I provide the details:

Problem Description:

  • Foundation Holes: The front of our house has several holes at the base, exposing the crawlspace. One is an actual crawlspace vent, but the other two are just gaps in the foundation.
  • Water Intrusion: During prolonged rain, water pools in front of the house and enters these holes, flooding the crawlspace. This has led to significant moisture damage, with the front walkway flooding up to ankle height.

Seeking Solutions:

  • Main Question: How can I effectively seal these foundation holes? I'm considering external sealing methods but am open to working from within the crawlspace if that's more effective.

Additional Context:

  • House Foundation: The left side of the house is on dirt, the right back side on concrete stilts, and the front seems to be concrete.
  • Crawlspace Condition: A vapor barrier is installed, but rain still causes subfloor swelling. The picture attached shows the door side of the house and the location of one of the holes.
  • Terrain and Roofing: The front yard is elevated, contributing to runoff towards the house. Our metal roof lacks gutters, exacerbating the front flooding.
  • Damage Extent: There is extreme subfloor swelling above the vapor barrier, although the back and dirt sides of the house are unaffected.

Professional Consultation:

  • Orkin's Assessment: A recommendation to encapsulate the crawlspace, install a dehumidifier, and treat the wood, estimated at $17,000, which is beyond my current budget.

My Plan:

  • I intend to seal the holes to prevent further rainwater intrusion before installing new flooring or carpet.

Long-Term Consideration:

  • I'm debating whether full encapsulation is necessary, given that the backside of the house is fine.

I'm a first-time homeowner looking for guidance from experienced individuals. Any advice on sealing techniques or alternative solutions would be greatly appreciated.

Visual Aids: I've uploaded pictures of the house and the problematic areas to my Google Drive: https://drive.google.com/drive/folders/1dVzcEBDtWLFJc4gVJxJrO1CCxpawPG2i?usp=sharing

Thank you in advance for your help!

  • 2
    Your best bet would be to fix the landscaping so that water doesn't pool at the side of the house. The water getting in through the crawl space vents is the part you can see. What's really concerning is the damage you can't see.
    – FreeMan
    Dec 15, 2023 at 18:18
  • 1
    You've told us nothing about foundation type, grade height, exterior finish, etc. Please revise to add enough detail for us to help, and include photos if possible.
    – isherwood
    Dec 15, 2023 at 20:06
  • 2
    And how about some pictures ? Dec 16, 2023 at 3:30
  • The issue appears to be the grade. By code, (check local codes, but probably about 6" in 10 ', or 15%), water must flow away. If water is toward the foundation you are not likely to solve the problem by sealing and could end up with larger problems. Also, when you try to sell the house, you may need to fix the grade issue or put in a drainage system.
    – RG Hughes
    Dec 17, 2023 at 12:54

1 Answer 1


First things first, fix the grading, so that water drains away from the house. Gutters are optional, but without fixing the grading won't solve the problem. Grading alone can solve that problem, though gutters with downspouts taking the roof runoff 10 or 20 feet out before releasing it will help, if the basic grading is sorted.

The slope required is not huge - 1/8" per foot (1cm/m) away from the house is generally indistinguishable from "flat" to the eye, but will drain water.

If the holes are in a concrete block foundation, mortar in a new concrete block. If the holes are in a poured concrete foundation, patch them with e.g. hydraulic cement. If you don't fix the grading, patching the holes will have minimal effect on your water intrusion, other than slowing bulk flow when it's ankle deep. A foundation is not a boat hull, and making a foundation equivalent to a boat hull requires a lot more work than regrading the surface.

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