On Oct 11, 3:41 pm, wrote:
Okay, I know this is probably a stupid question with an obvious
answer, but...How do I tell if my concrete basement floor is level or
not? It's not so bad that it's obviously wavy, but I don't want to
plan on finishing the basement with an engineered wood floor only to
find out that it's slightly out of level. I've heard as little as 10
mm over a 3m length will cause problems, but I am not sure how to
detect this amount of dip or rise. Thanks for any help!

Set a marble down on it. If it rolls away, the floor isn't level.
Make sure it's a metric marble.

JK

P.S. Most basement floors are sloped towards the drain.