crack in concrete floor

Old 12-16-08, 01:09 AM
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crack in concrete floor

My house has no basement -- everything is on a concrete slab. The house is 25-30ish years old and the last 15 years I have lived here, I have not noticed any water /flooding issues. Currently, I have ripped out the carpet and want to put in laminate flooring, but i have noticed a 1cm to 1/2 inch wide crack from the front door to the stairs. The visible crack length is about 5 feet. The concrete around it is not of different colour, so i don't think any water leaks from it (we just had a lot of rain lately too) I think the roots my neighbour's huge tree is causing this. Anyways, is this a concern to the foundation of the house? Should I be patching it up before I put in the laminate flooring?
Old 12-16-08, 07:23 AM
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My two cents:

It is impossible to determine the extent of your problem based on your description alone.
There is nothing no one in this forum can tell you, without looking at the problem, that will actually help you solve it.

Since it is a foundation issue, I think your best bet it to get a foundation repair company to examine the slab and tell you if it is a simple crack or something more serious like a foundation settling.

Foundation cracks and settling can happen for a number of different reasons, not just water damage, which according to you doesn't seem to be the case.

We can however rule out other possibilities, so please, get a pro to look at it.

The good news is, some companies will evaluate and give you an estimate for free, so it will cost you nothing to find out what is really happening.
Old 12-16-08, 08:02 AM
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And it depends on your definition of a slab.

My last house was considered a slab (no crawlspace), but it was completely seperate from the actual load bearing sections. I guess it would be more accurately called a raised slab foundation. The load bearing portion was trenched out, footer poured, then concrete block was put in. Then the inner area was filled with sand/gravel and concrete was poured. So the actual living area floor was not attached to the load bearing foundation.

There were some houses that were just trenched out and footers and floors were all one piece, reinforced with bar and wire I presume.

I've heard of some that seem pretty common that have tensioned cables running through the actual slab to hold everything together.

Can you see any cracking or shifting on the exterior foundation? Are the edges of the interior crack uneven in height or level? Most cracks from roots I've seen will raise the concrete, not just seperate it.

Anyway, depending on what type you have, I'd probably patch it and put in your floating floor. All concrete cracks.
Old 12-16-08, 05:41 PM
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in norman codes say the slab is separated from the foundation edge by a thermal barrier, so all floors are floating slabs. unless you have a basement. like gg said if the edges of the crack are the same height you most likely don't have a real problem, just expansion cracking.

Murphy was an optimist

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