How do I change the plumbing from a shower to a bathtub/shower?

Eallande26 you remove the shower pan/floor, etc. and you relocate and reduce the waste line and install a new tub, tub waste and overflow, and a new tub/shower valve. You should be able to use the same vent pipe from the shower unit for the tub unit... but that will all depend on piping configuration already set up. Then you tile again (if tiled) or add a tub surround wall.. depending on size of shower stall.

If a custom shower in place will probably need to do some rough framing and some concrete board work to make a space that will accommodate a tub/shower unit

Is this a concrete floor.. Basement.. Most tub/shower units come in 60" by some width units.. let us know if we can help more.

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