Why does nobody talk about subfloor flatness standards for vinyl plank?

I was installing vinyl plank in my sister's kitchen and kept hitting minor dips I thought were fine. A year later, she sent me a picture of a seam that had popped open. It hit me that the maker's flatness rules aren't just suggestions, they're critical for this floating stuff. My old habit from nailing down hardwood, where a little variance was okay, totally failed here. Now I use a longer level on every job and grind high spots religiously. It feels like extra work, but one callback taught me more than any manual. Do you all find that different flooring types really need their own prep mindset? I'm curious if this is common knowledge I just missed.

3 comments

3 Comments

casey9622mo ago

Heard contractors say prep is 80% of a good vinyl install.

mason_stone92mo ago

Totally. That 80% figure is dead on. Seen it myself with a friend's place. They skipped the floor leveler over a concrete slab that looked fine. Six months later, the joints near the fridge started popping. Those planks aren't forgiving at all. It's all about that flat surface, no bumps or dips. Otherwise the locks just give up.

paulyoung2mo ago

That's so true about vinyl plank prep! I read a forum post from an installer who said treating it like hardwood is a huge mistake. The locking systems on floating floors need perfect support or they stress and fail. Your sister's kitchen is proof that those tiny dips add up over time. It's a different ball game than gluedown tile where the adhesive fills gaps. Now I sweat the subfloor details more than the actual laying of the planks!