My house has a block foundation and water issues, I have a company coming soon to install a perimeter drainage system w/ sump pump and he said he's going to install a mill sheet vapor barrier about 4" high from the step stone and drill weep holes.

I'm looking to put up foam board insulation afterwords and my question is if I drill holes into the blocks to attach the boards will water start coming out of the holes? Would I be better off using an adhesive to attach the insulation? But will it adhere properly what with my foundation being cinder blocks?

  • 3
    It could. If you add a hole, water now has a place to go. Also, if you are getting water in there now, I would seriously consider holding off on the project until satisfied the water issue is resolved.
    – noybman
    Jan 19 '19 at 16:08
  • 5
    Hello, and welcome to Home Improvement. I'd talk to the drainage company; if they warranty their work they'll have an opinion on what may or may not break that warranty. Jan 19 '19 at 16:44

Drilling weep holes in your foundation can create additional problems.

Water problems around the foundation can be caused by: 1) High watertable, or 2) surface water runoff.

1) If you have a high watertable, a perimeter drain is a must. (Depending on the size of the house, we may run a few drainlines under the house too.) If water is in the crawl space and the drainpipes are not deep enough to collect the water, then weep holes through the foundation wall MIGHT be appropriate.

2) If water is collecting around the perimeter of the foundation, weep holes are NOT recommended, because water will run into the crawl space.

Btw, cinder blocks have voids and can fill with water. Weep holes will allow the water to drain out, but should be installed through the outer shell (face) only. Installing a hole through the inner shell will allow the water in the cells to drain into the crawl space.

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