What would cause floors to ripple?

[Matt McKinney]

Hey everyone! I have a single family home, built in 2009 new laminate floors installed in 2015. I have some tenants that moved in May of 2016 and the floors were perfectly fine. During the move out inspection the PM noted the floors were water damaged. PM said he thought water was coming in from the sub floor. It’s in a few different spots but all near each other, by the back door. The photos show a rippled and warped look and the edges cracked and broken as well as some scratches. The PM thought the crawl space might have flooded, sent someone out to check, that wasn’t it. Dry as a bone. Then thought an issue with the sub floor, not it either. Then lastly thought maybe the frame around the back door was letting water in. Frame is sealed up tight. Door installed and sealed properly. Not the cause. The PM is now at a loss as far as cause but I’m going to need new floors and would like to figure out the cause because 1. i dont want it to happen again and 2. If the tenants did somehow cause it I want to make sure they’re charged (PM was leaning toward problem with the house and not tenant cause) according to the tenants it just happened one day and they have no clue why. Any ideas?

[Scott Rogers]

Humidity can also cause it, if they didnt use the air conditioner trying to save cost.

Wet mopping can also cause it.  Laminate can be damp mopped but shouldnt be wet.

Im proper installation not allow proper expansion around the perimeter will also cause it.

Without pictures though it could be a number of things