[John Rogers]

Several questions: What is underneath? If a cellar then adding an enclosure on top of the existing tub would be easy. The lines to the shower head could be run underneath and up the wall. It would also allow you to reinforce the bottom of the existing tube with layers of sailboat fiberglass mat and resin. We had one and it lasted for around 25 years before a crack started right down the middle.

Also what is behind the wall(s) where you could mount a one piece surround to waterproof things. The picture showing the glass shower enclosure looks like will would not last long?

Personally I wish we still had our Jacuzzi tube in the main bathroom as I have gotten old and my joints ache and it used to help.