We purchased a home where the previous owner did a lot of home improvement himself. The house has a finished basement and I believe the previous owner mentioned something about him digging out and finishing it himself.

The basement recently developed a mildewy smell so we pulled up a corner of the basement carpeting. We discovered two things that really worried us. First, we discovered that the padding and carpet were placed directly on the concrete without any sort of moisture barrier.

But my question related to the second thing we discovered. The concrete slab in the finished part of the house has wood dividers embedded in it (they look like 2x4s but I can't be sure). See pictures. It's almost as if he framed out the flooring for pouring the concrete but then left the wood. Some of the wood is damp to the touch and seems to be starting to deteriorate.

I guess I'm looking for some confirmation that this is wrong and problematic. Am I wrong? Is there any legitimate reason for that wood to be there? I'm assuming I'm going to have to dig it out and fill the voids but would love to be wrong. (Not only does that seem like a big job, but some of the wood goes under the wall frames, so I may have to cut into the walls in order to get to the edges of the wood).

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    I don't see it as a problem (and maybe a boon for some reason down the road) except for the moisture issue. The wood is not causing the moisture problem, and concrete is porous so the moisture will be a problem with or without the wood. Commented Nov 12, 2020 at 2:05
  • Similar question - diy.stackexchange.com/q/203940/18078
    – Ecnerwal
    Commented Nov 12, 2020 at 2:19
  • Can you ascertain if the wood is pressure treated? 2) are they holding any load Commented Nov 12, 2020 at 3:28
  • is there a floor under the floor? Maybe they fixed a really cracked floor with some braced pours.
    – dandavis
    Commented Nov 12, 2020 at 7:56
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    It's highly unlikely to effect the structural integrity of the floor. Expansion joints are normally filled with a thick fiber material (like felt but heavy duty) which will also wick water, so the wood isn't really different, just wider
    – FreeMan
    Commented Nov 12, 2020 at 14:46

1 Answer 1


The concrete floor shouldn't be effected by the embedded lumber even if it should deteriorate. If the concrete floor was poured to an appropriate thickness and mixed correctly it's best to leave the wood in place. From your photo the first thought I had was they were used as striking boards when the floor was poured, but most people remove them after the concrete is leveled. On the positive side; they can be used as attachment points if you ever decide to install sleeper's for a finished floor.

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    You can seal over the wood to slow down decay. It probably won't help with the moisture coming in from the concrete, but it'll at least contain the air quality issue somewhat.
    – Nelson
    Commented Nov 18, 2020 at 7:00

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