I have 2 bathrooms, both with showers, and no room to convert either one into a tub. So I thought about building up the wall on one and converting it to a soaking tub. The shower is square with 3-sides wall, ceramic tile. The new wall would be built onto the front with maybe a low seat added inside and a step added outside. Any advice? How would I plug the shower drain?

Repost this in the plumbing section. Speedball should be able to answer this.

I have 2 bathrooms, both with showers, and no room to convert either one into a tub. So I thought about building up the wall on one and converting it to a soaking tub. The shower is square with 3-sides wall, ceramic tile. The new wall would be built onto the front with maybe a low seat added inside and a step added outside. Any advice? How would I plug the shower drain? the existing walls were build as water resistance( not water proof)), those walls will not able to hold as a tub

Good point caibuaddy