It’s been a while since the last update, where we had started to demolish the next room, but it is not for lack of activity.

The next basement room, with the bare concrete floor mostly ground clean.

The concrete floor has been ground using the same machine from Home Depot that we used in the previous room. This floor was in better shape in that it’s not crumbling like the other one did, but on the other hand it was quite uneven. Also, we need to get the old white paint off the concrete wall since it’s bubbling due to the efflorescence. This has meant quite an investment of time with an angle grinder and a diamond grinding disk.

The kitchen floor still needs to be ground down, but it’s a pretty small area:

The kitchen floor after ripping out the old linoleum. This is before any grinding.

The big uncertainty at this point is that there are a few spots along the internal concrete “wall” (it’s only an inch or two high) where moisture seems to be wicking up through the cracks where the carpet was nailed down. There are also a few areas on the concrete wall towards the front stairs that have visible moisture. This is not old moisture trapped in the concrete, because it gets more intense if the weather has been wet.

The cracks where the carpet nails went are visibly damp.

It’s very puzzling. My hypothesis is that this “wall” was put in before the floor (recall that the basement originally had a dirt floor) since it’s supporting vertical loads. If so, it probably goes all the way down to some solid rock. If there’s still moisture coming down under the house (the French drain doesn’t extend to under the stairs and towards the driveway) it would get trapped by this wall and then wick up through the concrete.

It’s hard to say without testing, which would require knocking a big hole in the floor and digging down to see what’s happening. Not an attractive prospect.