I am getting my basement bathroom finished. We found the concrete floor is not 100% level during tub installation. My plumber used mortar under the tub to level the tub. Please look at the gap between the tub's bottom and the floor.

Now I have to install vinyl plank flooring. Do I need to level the concrete floor first?

Thanks !

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  • Are you sure it's out that far? Did you flip or rotate the level to verify that it's accurate by checking opposite bubble directions? Plumbers tend to use very short levels which magnify any error in the level or the user. I've seen cabinet installers shim cabinets up substantially across a kitchen because they deemed the floor at the first cabinet out of level. It probably wasn't. Or it wasn't enough to matter.
    – isherwood
    Commented Aug 12, 2021 at 17:35
  • Measure from the tub rim at each end to the floor joists above. Does it show parallel?
    – isherwood
    Commented Aug 12, 2021 at 17:41
  • @isherwood, yes Commented Aug 14, 2021 at 15:04

1 Answer 1


OK I do no get why you need to level this. To be clear if you need to the tub doesn't care. Clean/prime area and pour leveler. No issues there.

However there isn't that much of a slant and I would only use leveler if there were holes/pits. Also the slant is going in a direction that is perfect. Your baseboards are the only way to really tell of a slant this small and since they are on perpendicular walls they should be relatively level.

When installing vinyl planks you don't need level though, you need flat. That bathroom looks flat. I see no reason at all to do this. (I have installed vinyl planks on basement bathrooms 20+ times - only one used leveler and only because bathroom was huge - 10x22).

  • 1
    side note... don't like that the front right edge of tub isn't supported. Won't notice until tub is full and someone is getting out... also that is where you install doors and curtain rods... put a 2x there for $4 and thank me later. Also what is going behind this tub?
    – DMoore
    Commented Aug 12, 2021 at 21:08
  • Thanks Dmoore, What does mean "front right edge of tub isn't supported" ? Also you mentioned to put a 2X4 on each side to hang curtain road ? If yes that I like that that one. I am installing Maui NexTile tub surround from home depot. Commented Aug 13, 2021 at 22:04
  • Also If I don't put self-level concrete then vaniyl plan won't look parallel to tub, especially at the bottom. Commented Aug 13, 2021 at 22:12

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