Designing Kitchens and Bathrooms - replacing sub floor in bathroom

We are currently trying to replace our flooring in the bathroom. There was peel & stick tiles so they were lifting and moisture got on the subfloor. We are going to be putting down ceramic tiles, but do not know how to replace the subfloor. Is it diffucult? Can a do-it-yourselfer do it??

Is the wood severely damaged by the water? How thick is the subflooring and what kind of wood is it, plywood, OSB or??? You will need a properly constructed subfloor with a layer of cement board in order to support the tile without them cracking. If the wood is beyond repair I will defer to another on the removal and replacement to answer but we can get you ready for the tile once that part is taken care of. The worst case scenario is if the wood is rotted under the tub and gotten into the floor joists.

We are currently trying to replace our flooring in the bathroom. There was peel & stick tiles so they were lifting and moisture got on the subfloor. We are going to be putting down ceramic tiles, but do not know how to replace the subfloor. Is it diffucult? Can a do-it-yourselfer do it??

Depends on your motivation and basic abilities. Essentially, you have to cut out the floor down to the joists... and replace it. It's not difficult - but is time consuming. I'm replacing the floor in my latest "fix n flip".... Used a "sawsall" to cut out the floor along the existing joists. Sistered 2X's along the edge joists to give myself something to nail the edges of the new floor to - and laid 3/4 tongue n groove flooring panels in place. The nice thing about removing the subfloor is that I'm able to run new electric wires/fixtures to the room downstairs while I'm at it - as well as the ability to fix/correct/improve the existing plumbing in the renovated bathroom.