1

I'm looking for advice for a good way to reduce moisture seepage through my basement concrete floor.

My research has turned up several promising approaches:

  • Surface-only treatments
    • Specialty paints
    • Normal paints with an epoxy additive mixed in just before use
  • Penetrating treatments (using various kinds of chemicals)
  • Accept the current level of moisture transmission, and just keep a dehumidifier going.

Within those categories listed above, I'm seeing a lot of mixed reviews regarding the products available on the market at HomeDepot, online, etc.

Note: Someone posted a very similar question back in 2011, but there doesn't seem to be a consensus among the replies. I'm hoping the passage of time brings new options or clarity.

Background:

I'm finishing part of my house's basement, which has a concrete floor. As best I can tell, there's a fair amount of moisture coming into the basement through that floor, particularly when the water table is high. My current focus is on one basement room (about 400 sq ft.) that's used as a den.

Some sections of that floor have a layer of battleship-gray paint that feels (to my untrained hands) latex-based. But that paint is in pretty bad shape, and only covers about 20% of the floor.

The middle 80% of the room was covered by commercial-grade carpet, and it seems to grew mildew/mold pretty often. Underneath that carpet, the concrete is mostly mottled black, with a line-pattern that suggests it was once tiled. I'm guessing that the black stuff is residue from whatever held the tiles to the concrete.

I'm not looking for a solution to prevent ingress of high-pressure water. I used to get occasional flooding in the basement from cracks in the walls, but I now have an internal (under-concrete) drainage system feeding into a sump well. I'm also not concerned about high-pressure water from the water table; there's good evidence that my two sump wells keep that under control.

I intend to put a new area rug over most of the floor, but I first want to minimize the risk of problems form moisture seeping up through that concrete. Unfortunately my research turned up lots of options, and I'm confused about which is the best for my situation.

Considerations:

Here's what I do/don't care about:

  • Near the walls of the room, there will be places where the new carpet does not cover the floor. I don't care much about how those parts look, but whatever paint / sealant / etc. I use should survive the occasional trauma of having furniture dragged over it.

  • I'd like to avoid using muriatic / HCl acid to prep the floor, because I'm not geared up for using it safely.

  • I definitely want to avoid using a chemical paint stripper like the kind sold by RustOleum. I tried it in one section, and the downsides far outweighed the upsides.

  • I don't want to spend lots of time / effort mechanically cleaning the floor (with a belt sander, etc.) But if it had to be either that or the chemicals listed above, I'd go for the mechanical approach.

  • I'd rather spend $300 for a 10-year solution than $600 for a 20-year solution.

  • I'm not dead-set against adding a subfloor, but I wasn't sure I could guarantee the integrity of its moisture barrier (polyethylene sheet or whatever). I was concerned that if that failed, and I had water or moist air trapped inside the subfloor, I'd have a massive problem with mildew, and fixing it would be an even bigger job than just replacing an area rug. But maybe laying down 6 mil polyethylene followed by a layer of self-leveling concrete would be a good solution. I'll give it some thought, thanks! – Christian Convey Jun 26 at 19:20
  • Have you looked into a sump pump? I'm not sure what it would cost to add at this point though. – Ben Jun 26 at 19:42
  • @Ben op states he has two sumps – Kris Jun 26 at 20:09
  • Missed that.... – Ben Jun 26 at 20:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.