I told the Realtor and prospective owner that I needed permission to do a little exploratory surgery. Under the window on the exterior would be an ideal location. The following picture was what I found behind the siding, from my test hole . . . Pretty ugly! Looked like a total gut out job, remove the tub, exterior wall and floor under the tub and then rebuild it all.
I suggested going with a normal tub, moving the plumbing to an end wall and take the shower head out of the ceiling. The extra space could be used for storage and moving the window to the end of the wall and out of the tub space,would take it out of the shower and away from the water that had caused the problem in the first place.
The owner agreed and I removed the tub. What a Mess! Everything was pretty far gone and would require re-framing the floor, walls and floor replacement. The plumbing had to be re-located for the new tub location. After a couple of long days the bathroom looked and smelled like a completely different room.
The owners were using the house for a rental and were anxious to get the project completed and also to have a normal - low maintenance bathroom. The Kohler tub and surround were made from a cast plastic that is quite rigid and also had the advantage of being
a deeper than normal soaking tub, without the additional cost of purchasing a custom unit. I was impressed with the interlocking - no caulk 3 piece tub surround. In the past these units required caulk that would discolor and mildew, which is unsightly and a maintenance item. The walls were cast with integral support ribs that made the surround rigid and durable. The interlocking seams directed all water back into the tub.
The space beyond the tub/shower wall held a 24" storage cabinet and I had a piece of Granite countertop that was a close match to the existing laminate vanity top to cap off the cabinet. I re-used the vinyl window after cleaning it up. The whole project came in on budget and will work well for years to come with very little maintenance required.