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stewart_mcmillan

Contractor removed dimple drain waterproofing system

4 years ago
last modified: 4 years ago

We recently hired someone to paint basement walls, epoxy basement floors, and put up drywall in a few targeted areas. This is a recently purchased 1937 home in Michigan, and our area was recently hit by bad flooding. Previous owners did some water damage restoration after the storm, and left it to next owner to make any other improvements.


Day 1 on the job the crew cut away the dimple drain baseboards/liners(pictured) that were installed in the home 6 years ago and 2 owners ago. I wasn't expecting this, and this waterproofing system wasn't discussed during the walkthrough/consult with the contractor. I don't know how important this dimple drain is, but it must have been put in there for a reason.


We already spoke with the contractor, and he said he will "make it right".


1. Is this kind of waterproofing systems worthwhile? Does it actually do anything?

2. If we paint walls with a basement appropriate paint(rather than with tar like we currently have), epoxy floors, and restore the dimple drain, will the waterproofing system still function properly?





Comments (4)

  • PRO
    4 years ago

    They ruined your waterproofing system. The holes that you see in the block are there to allow the water/moisture to bypass the block and get behind the dimpled membrane and from there diverted under the slab into a drain channel or pipe. By removing that now everything will be draining onto the surface.

    I see things like this on many occasions and it makes me wonder all the time if someone who does the work doesn't know what something is, why not ask before taking any action.

    That said, I hope they have insurance or are willing to pay for it, because now you need a new drain channel installed on top of the floor and seal it on top and bottom and run it to the sump pump something like a Drytrack channel. Here is an example to give you an idea.



    Good luck

    Stewart McMillan thanked GN Builders L.L.C
  • 4 years ago
    last modified: 4 years ago

    Thanks for your reply @GN Builders L.L.C. With the kind of system that we have, is there a drain that's been installed below the cement? Or is the drain simply the thin channel that's been cut into the cement around perimeter of the floor?


    It looks like the cement would have to be broken up around edge of the floor to remove and replace what's left of the system. Do you agree?

  • PRO
    4 years ago

    Yes if it was installed after the slab was in place the floor would be cut (hard to tell from the image if it was or not because of the leftover glue from an old flooring that was removed I assume).

    If this perimeter membrane was installed before the slab was poured there could be a drainpipe under there connected to the pump... If not it just drains under the slab, but if that's the case there should be 4" of stone with plastic under the slab and water will find its way to the pump, because if not your slab will be constantly wet.

    Stewart McMillan thanked GN Builders L.L.C
  • 4 years ago

    This is pretty much the system you have:



    The part you are missing is the plastic covering the wall - which helps direct water/moisture coming anywhere through the entire wall down to the interior perimeter drain, not just from the holes drilled through the bottom row of block. It will be harder to insert it having the dimple board cut off, but 'should' still be able to happen.

    Typically when you drill that many holes on the bottom row of block, you install an on-slab gutter system like GN shows. Then water can run on top the slab around to the new sump pit. When you choose the expensive version of tearing out the slab and installing a french drain and this dimpled board system, that usually means you have more intense underslab water and leaky walls.



    Stewart McMillan thanked 3onthetree