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basement floor cracks, recent movement

Posted by ken_in_kc ( on
Sun, Sep 20, 09 at 11:15

We were going to install vinyl plank flooring in our rec room basement but after pulling up all the carpeting we found a large raised crack running from the south wall to the east wall, about 15-20ft long. One end of this crack I had put some leveling compound on about 5 months ago while the carpeting was pulled back for another small project. I see now it has moved horizontal about 1/16 inch since.

There is an area where the crack is about 3/16 to 1/4" wide and a vertical rise of maybe 3/16". For most of the crack's length, the rise and spread aren't too bad - 1/8" or less. We haven't had water come from this large crack and have lived here over 20 years.

The house is a early 70's split level on a sloping yard. West end of the rec room floor is actually above grade (that foundation wall piered), and 2 sides (north and east) have a subfloor drain with sump pump. The water was coming from the wall and/or wall-floor joint.

So I guess my question is could the crack be stabilized with epoxy or ? and should the idea of the vinyl plank flooring be scrapped even if we smooth and level the cracks? We are considering going with carpet again because of the floor movement. Or can the vinyl plank flooring take a little floor movement without creating gaps?

Thanks in advance.


Follow-Up Postings:

RE: basement floor cracks, recent movement

You mention a couple of things:

The crack has increased by 1/16" in the last 5 months.

You've lived in this house for 20 years; and you have a sloping yard.

I would recommend having a GeoTech Engineer taking a look. This is not expensive. Probably around $200 for an initial visit; and you can talk with him/her on the phone first, and they will tell you if they should come out, or a different type of engineer.

Concrete doesn't 'just' crack. It cracks because of expansion, or cracks because of movement. Movement caused by soil erosion, etc.

Just because the house has been around awhile - doesn't mean your not now experiencing some significant foundation issues. I'm just finishing up a majory retrofit, and complete redo of the house my lovely wife grew up in... When she was growing up - her parents were always patching walls, etc. of the house. The house had signficant soil erosion on a slope, and we ended up fixing this by pin pilings, and engineering work. Would have been much simpler if done a long time ago. The house had existed for quite some time also - before it started having foundation problems. Had a crack in the basement floor....

Anyway - you've stated that this crack is moving and growing. Why not bring in a GeoTech (soil engineer0; or someone else of similar training/expertise - and find out what is going on... before you end up with lots more problems later - down the road...

RE: basement floor cracks, recent movement

Thanks, Dave. I had thought about doing this - bringing in an engineer or someone other than a foundation repair company to get more of a non-biased opinion.

To: Dave777 2009

Just read your response to a writer about a crack in the cement floor. I've had my house for a year, and noticed a new crack this summer...lots of ledge around the house, BUT also new construction that might have affected runoff water. should I be considering a geo engineer as well>

RE: basement floor cracks, recent movement

Small shrinkage cracks in a newly-poured concrete floor are normal and not even warrantied under the government plan I
build under. Settlement on the floor less than 12mm needn't even be repaired. Cracks in floors or walls exceeding 5.99 mm must be repaired.

New cracks after many years of stability might be of concern in an older house. That said, many of the older homes--80 yrs.+--I've owned had considerable areas of lift, settlement and cracking in the floors that never concerned me. A basement slab is non structural. Some experts have speculated that many of these may be result of the small earthquakes that have occurred over the years. Others were caused by frost heave. Foundation cracks are another matter and should be investigated further.

Here is a link that might be useful: Foundation Crack Bible

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