Can You Add a Steam Shower to an Existing Bathroom?

Published September 27, 2026

Summary

Sometimes. The generator is usually not the hardest part. The existing shower has to become a fully enclosed space built for repeated steam exposure, and that may mean changes to the ceiling, glass, waterproofing, steam-head location, controls, plumbing, drainage, and electrical work. If the shower was never designed for steam, the hidden wall and ceiling assembly may be the deciding factor.

First, can the shower contain steam?

Open-top showers and partial glass screens are meant to let humid air escape into the bathroom. Steam mode needs a much more contained enclosure.

The ceiling, walls, door, and penetrations all have to tolerate repeated vapor exposure. Asked whether an existing tub or shower needs to be modified, MrSteam answers "Most do," because all walls and the ceiling have to be watertight.

Second, where will the generator go?

The generator belongs outside the steam enclosure in a dry, protected, serviceable location. ThermaSol's PRO Series III manual lists a closet, vanity cabinet, or climate-controlled attic or basement up to 50 feet from the shower, with 6 inches of clearance and a drain pan under every generator. MrSteam allows up to 60 feet and asks for 12 inches of space around the unit.

Wherever it goes, the generator needs service access and a reasonable route for the steam line, water, electrical supply, and drainage.

Third, can the utilities reach it without rebuilding everything?

The generator needs water, electrical power, a steam line, and whatever drainage or flushing arrangement the model specifies.

ThermaSol's manual does cover fitting the steam outlet into an existing finished wall: it goes through a 1-1/8-inch hole, but the plumbing has to be done from the back side of the wall. That is one reason a bathroom remodel is the easiest time to add steam. When the walls are open, the electrician, plumber, and tile contractor can coordinate the hidden work before finishes go back on.

Sometimes rebuilding the shower is the simpler answer

A very small shower, an open ceiling, unsuitable wall construction, or a poor generator location can make a surface-level conversion expensive and awkward.

If the existing enclosure has to come apart to be made steam-ready, the job is a new custom shower with a generator, and it should be priced against conversion before the generator is bought.

Sources

Specifications, prices and installation requirements are as the makers published them on these pages on the date above and can change. Check the current manual and the retailer before you buy.