We had a spot beside our washer & dryer in our finished basement with a 2" drain in the concrete floor. But to make it a soaking tub the drain needed to be modified to hold a popup plug (more about this later).
Next my hubby roughed in the space with 2 x 2 lumber and cement board as the budget didn't allow for a wooden vessel.
To make it water tight a waterproof membrane was rolled onto all walls, ceiling and eventually the floor. I used Redgard which was easy to work with, dried fast (1.5 to 12 hours) and cleaned up with water before it dried.
The floor needed to be built up in order to slope towards the drain. We used a combination of layers which included regular concrete mix ($7/bag) , King top n' bond ($26/bag) and modified mortar($18/bag). The gravel in the concrete mix made it difficult to get a good slope so I wouldn't recommend using it for this purpose and top n' bond was too expensive and not necessary. **Don't use self-leveling cement or you won't get a slope at all.
We needed a shower for our Japanese exchange students in October '08 before we could finish the floor, so I tiled the walls leaving enough room on the bottom to finish the floor in the future. That's where the project stopped until now.
On Sunday some friends (actually Special-K's boyfriend and future father-in-law) came to help me finish that slope towards the drain.
Yesterday, it was cured enough to roll on the Redgard. I made sure to push the goopy material into any cracks and crevasses, and paid special attention to getting the corners well saturated and tied into the wall membrane I previously rolled on. I used a stick to get the goop out.
The Redgard is dry and ready for tile when it turns completely red from a beautiful shade of pink (1.5 to 12 hours).
Wash your hands or any spills with soap and water immediately before it dries (unless you like the design detail)
Tiling is on my to-do list for today so check back in the next day or two to see the progress.
Have a great day!