I’ve learned the hard way that skipping a proper vapor barrier is just asking for trouble, especially if you’re renting the place out. I like to lay things out step by step—first, check for any cracks or signs of previous moisture issues in the slab. Patch those up before anything else. Then, I always go with a 6-mil poly barrier under whatever floor goes in. Even with floating floors, I don’t trust those “all-in-one” underlayments unless I see the specs myself.
Curious—did you do any moisture testing before starting? Sometimes folks skip that and it bites them later...
Yeah, skipping moisture testing is a gamble I learned not to take after a basement job went sideways on me—ended up with warped boards and a lot of headaches. I usually tape down a square of plastic for a couple days just to see if any condensation shows up. Not the fanciest method, but it’s saved me more than once. Those “all-in-one” underlayments always make me nervous too... specs or not, I’d rather stick with what I know works.