I have roughly 600 sq ft of basement that needs new flooring after some unfortunate flooding this past summer. We had carpet over concrete and are now looking to lay vinyl planks down. There is about 150 sq ft off to the side (L-shaped basement) that is very uneven.

I'm a first time home owner, inexperienced with these types of jobs, and just trying to figure out the best way to approach this.

Do we try to level out the higher area only? Grind it down, or self leveling concrete? Or lay down a subfloor throughout the entire basement?

The majority of the floor is even, with one section that was possibly a crack in the foundation "repaired" by a previous owner. Max variation is nearly 1/4" in some spots around the edge of that patch. They had laid some ugly VCT over top to try and hide it.

And yes, the water problem has since been solved. And if it makes a difference, the area that has the raised patch is not the area we had water issues.

Any advice is greatly appreciated!

  • 2
    How uneven is the floor? What's the max variation between the highest and lowest points? Commented Dec 4, 2012 at 21:28
  • 5
    is the water problem solved? Commented Dec 4, 2012 at 21:48
  • How much of the space is that much of a variation? If it's a few spots, might be easier to just grind them down.
    – QuaffAPint
    Commented Jan 19, 2013 at 18:44
  • It really depends on why the spots are uneven. Do you have pictures?
    – DMoore
    Commented May 17, 2013 at 4:11
  • why not just use a quick cement and fill the low gradual so it isn't perfect, but inexpensively flattened?
    – user43458
    Commented Sep 13, 2015 at 14:36

3 Answers 3


Type of flooring dictates how "perfect" it needs to be, carpet being the least work. Vinyl is flexible so just no real drastic changes.

Below are the basic steps to fixing uneven concrete floors.

Use a straight edge and mark high and low spots. (Really exaggerated case in this image) Straight Edge

Or if you like gadgets, Bosch has a new laser out that lets you easily mark the uneven parts. Bosch GSL2 Laser

You use a grinder (with dust mask and safety goggles) for high spots. You can rent a large floor grinder or get on your hands and knees. Grinding Floor

and SLC (self-leveling compound) in low spots. For SLC just follow the manufacturer's instructions. If the floor is really bad you may want to pour the stuff over the whole thing. SLC 01

SLC 02


For a basement, it might not be worth the cost. If your floor is just rolling, then you should be able to install vinyl tiles directly. What you need to get rid of is any sharp changes in height such as lumps of concrete spatter and any ridges that have a sharp edge.

Your floor won't be perfect, but trying to grind it down is a lot of work, and self-leveling compounds are expensive.

  • What are your thoughts on strategic use of patch and skim coat for low areas?
    – Brian G
    Commented Apr 2, 2019 at 1:58

If you do not have experience with concrete or self-leveling floor compounds, I recommend a sub-floor, or hiring a contractor. Installing a sub-floor is a little bit more forgiving of mistakes (easier to fix in other words)...

That said, if you can just partially level the floor to remove high points you might be able to use any number of floor tiles that make this easier. The ones I have seen used had a black plastic bottom with wood top surface and inter-connected.

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