How to level an uneven floor

I've seen a lot of bad tiling jobs and it is usually because the floor wasn't leveled properly. Here are some signs your floors are uneven:
👍 Does your floor slope?
👍 Are you noticing high spots?
👍 Are areas of your floor squeaking?
👍 Is there bounce and movement when someone walks across it?
👍 Are the tiles or grout cracking?

[joequillun]

I agree. Could've used more info.