I want to build some basement shelving units but my basement floor slopes away from the wall for drainage purposes. I'm not sure if I should build the shelving so it's square with the wall or with the floor. Here are the pros/cons that I could think of for each method.

Square with wall

  • Pros
    • Will look straight
  • Cons
    • Technically crooked
    • Can't relocate to a flatter location without being crooked

Square with floor

  • Pros
    • Technically straight/square
    • Can relocated to other area
  • Cons
    • Will look crooked with gap at top against the wall

Is there an obvious reason I'm missing on why I should do it one way over the other?

  • 1
    It is pretty common for walls to not even be perfectly square to each other. I'm not sure how much of a gap you're talking about, but have you considered building it square itself and putting a shim under it to level out the floor?
    – rob
    Commented Jan 11, 2018 at 16:21
  • @rob I did not consider using shims. That seems like the perfect solution. Thank you.
    – Programmer
    Commented Jan 11, 2018 at 16:25
  • 2
    Another consideration is that a shelf that is not level has a tendency to shed its contents :)
    – Ast Pace
    Commented Jan 11, 2018 at 18:00
  • @rob : That should be an answer, not a comment. Commented Jan 11, 2018 at 19:06
  • 1
    @MartinBonner ha, yeah I was just being a little lazy earlier when I stopped by the site quick. I've rewritten it as an answer now. :)
    – rob
    Commented Jan 11, 2018 at 23:03

3 Answers 3


Another solution you did not list would be to go ahead and build the shelf to be square itself, then shim underneath it to level out the floor. That way you can move it anytime but also make it look straight against the wall.

  • 2
    If you wanted to get fancy you could also use adjustable feet
    – Steven
    Commented Jan 12, 2018 at 1:14

Expanding a bit, perhaps, on rob's answer, cabinetry (including shelving units) should be level and plumb (so aligned with the earth's gravitational field) and shimmed or scribed/trimmed/fitted as required to fit it to the space it occupies.

This is generally important to its function, so things don't roll off or fall over for example. It also may be the best looking (or close to it) because as humans we have a keen sense of the gravitational field we live in and things will look "off" if not aligned with that, even if the adjacent wall or floor is slanted. I'm not saying that will look great in that case, just that making the cabinet match isn't necessarily going to make it look better, and it definitely won't feel better in use when things roll around or books fall over.


There are floor leveling systems you could try that I’ve used for tile laying before, it even works great outside but may want to match the color or not since it’s going to have a shelf over it anyhow. Just a thought.

  • I don't think leveling my entire basement floor is an option. It was designed to allow drainage into the drains that are in the concrete floor. Also would be hard since all of the water/HVAC systems are located down there.
    – Programmer
    Commented Jan 15, 2018 at 15:07
  • Yeah you can still drain all that with the floor leveling but I wasn’t meaning the entire floor anyhow my friend, just whatever is under the shelf but hey, a shimming is a result that’s less worry, money, and time. Especially just for a simple shelf.
    – user5488
    Commented Jan 17, 2018 at 18:19

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.