# leveling concrete floor



## Cyrus (Sep 23, 2007)

Hi
My basement has an unlevel 600 sqf concrete floor. There should about one and half inchs difference between the lowest and highest parts of it.(There are 2-3 "bumps" about 10 feet apart). I want to instal Dricore in the basement (already bought them with an excellent price from a contractor), so I need to maske the floor level (Accrording to Dricore the floor can be at most 1/4 inch unleveled).
I was thinking of using self leveling compound but considering the area and the surface beilg unleveled about 1 1/2 inches it will cost a lot. 
How can I level the floor? I have done a lot DIY projects but never worked with concret. 
Thanks

Cyrus


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## DeeTee (Aug 29, 2007)

*They're All Hard options*

Depending upon how thick the concrete is you can also grind down the high spots. You may need to use grinding to lower high spots and floating to raise low spots. There is a floor grinder you can rent that uses some abrasive stones on its base. Here's an example of one. A more refined approach would be to pour some new concrete down there.:yes:


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## Cyrus (Sep 23, 2007)

DeeTee said:


> Depending upon how thick the concrete is you can also grind down the high spots. You may need to use grinding to lower high spots and floating to raise low spots. There is a floor grinder you can rent that uses some abrasive stones on its base. Here's an example of one. A more refined approach would be to pour some new concrete down there.:yes:


Thanks. Grinding seems very good solution.
The bumpy areas of the concrete have some cracks. I am not sure if the cracks have been caused by bumps. Is there the possibility that grinding the concrete in high spots somehow makes the whole fundadtion weak? I think I have to remove about an inch is some spots.
Cyrus


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## DeeTee (Aug 29, 2007)

*More Mystery*

It would be interesting to know why the bumps are there and knowing that answer might answer some of your other questions. Is it just poor workmanship, or poor workmanship combined with plumbing pipes not set deep enough below the slab, or other? One way to find out would be to chip up a small portion where the bumps are and see what you discover. To get an overall idea of how thick the concrete is you could use a concrete bit and drill some holes in various places and then insert a pencil or something into the holes to get an idea of the thickness. That way you can get an idea of how much you could grind down. This might also warn you if there is rebar buried in the slab and give you an idea of how deep it is. Grinding into a web of rebar won’t help your cause any if the rebar is still too high up in the floor. 

In theory, and if your place was built well, the walls of the basement should rest on footers and those take the weight of the building. Usually the slab carries the weight of the things you place on it. However, if there are posts or lally columns (round vertical pipes) that are supporting your floor above then those areas beneath those supports would also be load bearing and you wouldn’t want to disturb those either.


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## jmancine (Oct 11, 2007)

If your slab is going to continue to settle, it might be a waste of money to lay down the good expensive self-leveling compound. It might just end up buckling in a few years anyway.

I poured regular concrete (mixed thin) to fill a 2" dip in one corner of the basement floor. It worked great and has held up great -- though it is just a utility area that I never intend to finish. If you find some of the masonry guys out there they could probably tell you what sands/gravels/etc would mix best to cover your floor.


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## KUIPORNG (Jan 11, 2006)

I am yet to see a perfect level concrete floor..... even those in the condo... they are not perfect... not to mentioned the basement.... I think if the floor being slope gradually from one end to another... you should be ok and don't worry about it... for regular down spots and up spots... I would just try to shim it make it less obvious up and down ... unless the up spot is really sharp which you can hammer it off... even you don't do anything just laying dricore directly, I don't think you will make the situation worse .... you may have bouncy thing for a while, but after a little while and heavy furniture and eveything, I believe it will settle down...


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