I am prepping my basement concrete flooring to install click lock hardwood. The problem I saw is that there is a spot in the corner with this:

enter image description here

I am not sure what it is as it looks like a cap to cover something. BUT the problem is that area is a bit higher (like 0.5" difference with the cap).

What should I do to prep the surface for click lock floating floor installation?

Do I need to put down any underlayment?

Or should I just ignore this and it will be OK?


  • What are you referring to that's 2 inches high? All I see is a plumbing cap that barely extends above the concrete. Is there a mound in the concrete that's not apparent from the angle of the photo? – isherwood Jan 14 at 14:46
  • It is not 2". Sorry it was a typo. It's probably just 0.5" difference over 5' span I suspect. – HP. Jan 14 at 19:00

Assuming that the issue is a bulge in the concrete, I'd be fixing that first. You cannot lay wood flooring over that severe of a bend. Either break up the hump and remove it, or cut out the entire area and refill with concrete.

You'll want to shorten the pipe and install a cleanout plug (threaded fitting). This should be slightly below the surface of the concrete. You can then install a stainless steel cover after the flooring is installed.

  • Is it OK to use self leveling concrete? Also, is it possible to get around by using thick underlayment to smooth it out? – HP. Jan 14 at 19:01
  • I don't know how you'd use self-leveling cement in this case, and I can't imagine how you'd build up 2" with underlayment. Rent yourself a diamond saw and get to it. :) – isherwood Jan 14 at 19:02
  • It is not 2". It is about 1/2" (typo earlier). – HP. Jan 14 at 19:03
  • Still. You'd rather purchase and lay something over the entire floor than make this repair? – isherwood Jan 14 at 19:05
  • I can make the repair. I am not sure what is below the cap there. What happened if I break the entire drain pipe? And if I remove the hump, what is the ideal tool for this? – HP. Jan 14 at 19:26

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