I've asked a few questions about a basement finishing project already. Well, after getting more skeptical of the contractor who framed the room out, I reached out to the waterproofing company that installed the french drain to ask if there's anything they'd want us to keep in mind when finishing part of the basement. Should've asked months ago, but here we are.

Waterproofing contractor we worked with over a year ago said the finishing project as planned should be fine, they didn't comment or express concern about the contractor using non-PT wood on the concrete, but they did say the bottom plates should not be anchored into their concrete over the french drain or that could cause problems. They suggested glue or liquid nails. As a photo below shows, the contractor did ramset nails into concrete, with no change over the french drain's thinner concrete.

bottom plate over french drain

zoom in on nail for bottom plate

At this point, I'm wondering what my best course of action is (in terms of overall cost and safety). To me, the scenarios seem like the following.

  1. Fix the framing now, which would mean using a reciprocating saw to cut studs off the bottom plates, prying up bottom plates and inevitably chunks of concrete with it, patching concrete with hydraulic cement, and then reinstalling with PT bottom plates and gluing to french drain areas. I imagine some or all studs may be damaged in the process, so then there's sistering studs to make a sturdy connection again.

  2. Leave the framing as is, since what's done is done. Finish the walls, and in the end install one or two small hatches that allow for inspection of the bottom plate, insulation, wall behind, and studs. If problems do emerge, I expect it would be with the french drain's concrete cracking and/or wicking up moisture into the bottom plate, which would show up in 5 to 15 years as mildew stains or softening of bottom plate wood. In that case, I'd do the same as option 1, but it would involve cutting out the bottom 2ft of gypsum board and mineral wool batts and redoing all that after fixing framing.

  3. Leave as is, and it could be fine for decades, with inspection of the wall assembly's interior every year or so.

Scenario 2 doesn't seem much worse than scenario 1 (both seem miserable but doable if needed). And importantly, Scenario 2 leaves the possibility for a peaceful scenario 3 where this is all fine as is, avoiding costs of redoing work. I'm inclined to accept what's done is done and move on with monitoring and a plan if something comes up.

I don't know what I might be missing, so I'm asking what scenario is the most realistically economical to your expert eye. I don't mean for this to be opinion based, as I expect professionals would have a good idea based on facts at this stage: is it more economically prudent to go with scenario 1 and start redoing work, or to leave for now and aim for a scenario 2/3? Economic in terms of costs of material and labor, as well as any risks of damage to drainage system or other components, hazards of mold of rot is unnoticed and neglected, etc.

1 Answer 1


This is really hard to answer and I understand all of the variables.

First by code everywhere around me requires PT lumber for the bottom plate. I find this a bit funny in a way because if you have water issues long enough to rot regular lumber then mold and all kinds of other things are going to destroy walls. The idea of PT lumber needed for "mild" water to uphold for 200 years vs regular lumber holding 150 years is sort of comical. That being said, never used anything but PT because I knew if an inspector saw it, no way I am cutting out the bottom plate. So if your basement is going to be inspected, I suspect you better ask your city if they need to see PT. If yes, this answers your question.

Now in regards to "how should I frame this?" I don't see how tapcons being taken out and then you gluing would have that much of an effect on the quality of the wall in the future. That seems like a lot of work for no reward.

However if this french drain is heavily used and there is water, the wall should have been framed out more - 4-6". That would have allowed more airflow for water to breathe and evaporate and kept the framing and drywall out of water.

How do you frame over french drains? I usually have them out further as already noted then glue them down. My opinion is the glue is kind of useless and can/will fail especially with water there. So really what supports the wall is it being tight to the top PLUS I will add very small amounts of blocking on the bottom plate in the gap. Remember if you are sort of tight then really the wall can only be kicked in (which can happen so make sure to block walls more than an inch away from concrete) so two little pieces of lumber and a couple nails and you are good to go.

What I would do? If this were my basement and it wasn't being inspected and didn't get lots of water... I would leave it. Pro tip on wet areas like this... You install the drywall above the bottom plate. Baseboards are a little harder to punch in but this allows water to never hit drywall and gives you line of site on water issues.

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