Basement Floor Uneven - Thoughts on Causes?


Old 09-09-14, 11:50 AM
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Basement Floor Uneven - Thoughts on Causes?

Hi all - first post so bear with me, please.

I recently purchased a 100+ yr old rowhome and there are some issues with the basement floor. I have three basic questions about the floor:

1. What is causing the big "bubble" that is raised up in the pictures? The bump is about 1.5-2 inches above grade on the rest of the floor, although none of the floor is perfectly level, and is the worst place for unevenness. The bump is in the middle of the room, rather than close to any walls, if that makes any difference.

2. What would pouring a new floor/repairing the mystery bump cost at least in terms of a ballpark figure?

3. The obvious - vinyl 3% asbestos tile that is not in the best shape covers the entire floor as can be seen from the pictures. Am I completely nuts to remove this myself - using all the required precautions for remediators except a negative air machine? I've heard that it is fine to seal asbestos tile, but I also don't know if this is possibility because the tile is not in great shape and I won't be able to repair the floor underneath unless the tile comes out.

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Old 09-09-14, 11:56 AM
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Welcome to the forums.

If you know there is asbestos in the materials, I would have them professionally removed just so the liability then falls on someone else.

With the vinyl removed, you'll know more about the bump.
Old 09-24-14, 04:10 PM
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Basement Hump now Basement Hole

Thanks for the response, Mitch. I knew using a professional remediator for the asbestos would be the only answer here, as it was the only one I had gotten anywhere else. I'm an attorney, so I understand the liability issues (that is also what drove me to research whether I could legally do this myself and put that idea in my head, unfortunately). I have gotten quotes and a licensed pro is scheduled to remove the tile.

Because I have no patience, and my curiosity was driving me nuts, I poked the hump a couple of times with a crowbar and it popped right through (my wife was less than happy about this). At least from doing this, I am fairly sure it is a problem with the floor rising in a few places rather than the floor sinking mostly everywhere. Pretty clearly, there is not three inches of concrete underneath or any reinforcing.

I would guess that the bubble is a result of moisture and the lack of any barrier underneath, but that would just be a guess. I know there are cast iron pipes for at least part of our plumbing in the basement, too. I guess my question is - do I really need to know why it was like that, or can I just start thinking about pouring a new slab?

Any guidance, suggestions, or references to a trustworthy contractor that does this sort of work in the Baltimore area would be greatly appreciated.

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Old 09-25-14, 05:15 AM
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you can do this work yourself w/o being encumbered by govt regulations that apply to licensed asbestos specialists & other companies however disposal methods & locations still apply to all
Old 09-25-14, 07:10 AM
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Just an opinion from the free seats. Having the asbestos professionally removed puts an end to any future questions and provides you and future owners some level of proof this was done right. Save the receipt.

Now, for the bump. Judging from the picture that doesn't look like that floor had a very good mix. Even 3" of good concrete can be very solid. As for the question, did the entire floor move down, except the bump, or did the bump move up, I would think the floor moved down. Unless some of the pros can help with an explanation as to how concrete can bulge up on its own, there would be no force below that floor to do the pushing. Any water pressure from below that might have pushed that floor up would have turned that basement into a swimming pool. Was the basement ever totally flooded?

I know clay can expand and contract and does raise havoc in areas like TX where there is a lot of it, but I can't tell from the picture what is down there. Once you open up that area you may be better able to identify why this happened and why is good to know to be sure it doesn't happen again.

Old 09-30-14, 03:34 PM
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It is definitely possible that the entire basement flooded at one point, and I would say likely, because there is a sump pump installed that was put in within the past 15 or so years. Just about nothing else was ever done down in the basement, so I would think the sump pump was put in out of necessity.

Thanks for the input - I came here for the free seats advice!
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