Questionable subfloor in bathroom

Hi all,

As indicated in some of my other recent posts I am trying to remodel my half bath. Before I removed the toilet I noticed the top layer of flooring looked dark so i suspected a problem. Today I got both layers of flooring up. I believe it was laminate flooring, it looked like the cheap kind you'd buy on a roll at the home improvement store. All around the toilet drain, the board looks to have risen up due to water damage. As shown in my picture it is kind of chipping in that area.

Obviously I can't just put another layer on top of this. The good news is it doesn't look like the structural 2x4's(?) are damaged. I went in the basement and they look good. There is a small darker area around the drain but I don't think that will be a big deal (please let me know if it is!). Are my structural pieces OK?

Do I just need to pull the screws out for this top layer thin board and remove it completely? I assume there's no point in trying to remove the adhesive from it. My last concern is the baseboard heater pipes. It's not going to be an option to cut them because it's winter so whatever I do I'll have to work around them.

Any help or advice would be appreciated. Thanks!

 

I would cut around the perimeter of the plywood where you have the heater and remove it, replacing with 1/2" plywood. Do you know what size plywood is there presently? Once you have removed it, you can better determine the amount of damage, if any, to underlying support or planks. A multimaster type tool would be best to accomplish the cuts.