I just had my water heater replaced and found this mess underneath it. I had planned to peel up the sheet vinyl and replace it with vinyl planks. I did this in the kitchen with no problems. The problem is that there is a thin layer of plywood on top of the VAT everywhere except where the water heater is. I'm not sure what to do about the irregular shaped hole in the plywood. Three of the tiles are firmly stuck under the plywood, but the one in the bottom right is completely loose. There is also a hole drilled completely through to the crawlspace that someone just shoved a rag into. Any suggestions for how to fix this would be greatly appreciated.