I want to install carpet tile over DRIcore on my concrete basement floor. The floor is far from flat; I would guess at least an inch or two of overall variation.

Do I need to ensure the floor is flat for the DRIcore? If so, how would I do this? I see they make integrated plastic shims, but they are apparently only designed to adjust the height by 1/4".

  • Boy, you are Mr. Famous Question aren't you? Commented Oct 10, 2015 at 15:12
  • @TylerDurden what do you mean? Commented Oct 10, 2015 at 15:17
  • 1
    10% of your questions are famous questions, that is a pretty amazing percentage. Commented Oct 10, 2015 at 15:18

2 Answers 2


In my opinion yes, you need to eliminate the dips. Anything that will be spanned over a low spot by the Dricore will move under foot. It is after all only a high grade OSB and the T&G joints will eventually fail somewhere over time.

The whole floor does not have to be level, just on the same plane.

On a concrete floor, a laser level will drive you crazy, do not do that to yourself. Technically, it needs to be flat, ideally it should be level, but level is not critical. I see eyes rolling now.... A string line will give you a good idea of what is in plane, not relying on it needing to be level. I refer to a level as a straight edge only, not using the bubble to determine level. Usually a level is always straight, therefore a good candidate for checking flatness over a given area. It is a lot of "hands and knees work". Scoot the level all over the floor to see how the floor plane is in any 4 ft span. This will help locate the high spots. Situate the level or straight edge over 2 high spots, anything over a 1/16" needs shimmed.

  • I wouldn't have to use a laser level or string? How can the four foot level work for a large area? Commented Oct 10, 2015 at 17:31
  • I added the comment to my answer above.
    – Jack
    Commented Oct 10, 2015 at 18:08
  • Thanks, accepted; also edited my question to "flat" rather than level. I never actually thought it needed to be literally level, only free of dips. Commented Oct 10, 2015 at 19:24

The DRIcore website says:

Any dips or low spots in the concrete surface greater than 1/4" should be trowelled level with a Portland cement compound or leveled with a self-leveling compound to ensure an accurate installation.

I'm still not sure whether or not it's necessary with carpet tiles though.

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