If that was not vaporproofed properly, then there is a risk. 100% Vapor proofing is a step above 100% waterproofing. What system was used to vaporproof the entire shower? A plastic liner pan is not gonna cut it. Moisture vapor will pass through an non vapor proofed assembly snd condensate against the walls and equipment. A steam shower isn’t just a shower with a steam generator. It’s built entirely differently. 15-20K average, done the right way.

@User, from what I read online, a steam shower should only cost $2k-$4k (tiled, glass enclosure, equipment, etc.). $15-20k sounds excessively expensive.

Can you please explain what vapor proofing is?

I don’t know where you got that ridiculous number. The glass alone is more than that. Every build category that goes into that project is more than 2K. Adding all of the categories up for the needed equipment, dedicated electrical line, and the added framing, specialty custom glass, and vapor proofing takes the typical 8-11K shower to 15-20K.

Steam vapor molecules are smaller than water molecules. Water will pass right through cement board in a nice little stream, but steam runs through it like an expressway. When steam contacts the insulation and framing, or plumbing, or anything, at a lower temperature, it condenses on that surface and turns back to water. Water inside your walls, or electrical equipment, is very bad news for your house. Rot, mold, and shock hazards result.

Steam showers must be vslorproofed 360. All surfaces. The ceiling must be reframed to slope, so that the condensation on it doesn’t drip on you during use. The glass enclosure must be vaporproof, with a transom, in order to ventilate it and dry it out after use. The lights must be specialty vaporproof, and integrated into the vaporproofing membrane. The steam generator must be in an accessible location, and vaporproofed, wired and plumbed correctly. Without the right vapor proofing, it might as well be IN the shower. It’s not protected from water in vapor or liquid form either one. So yes, it is a shock risk if built incorrectly. As this is.

Hire wisely, or skip doing it. Even a regular shower needs more waterproofing than is in that picture. So you’re already faced with a complete rebuild, just for a standard non steam shower.

https://www.ceramictilefoundation.org/find-certified-tile-installers

I won't quote electrical code to you, but are you positive that your plans are fully compliant? Will this be permitted and done by a licensed pro?

Unless you plan to have an open bench, the generator isn’t “in” the shower. It‘s like a whirlpool tub with the pump underneath. Edit: Just realized the generator is inside the curb. Yeah, you don’t want to do that.

@Sammy - Agreed. That was my thinking as well, but the fact that it's in the same mud pan concerned me a bit.

Without the correct vapor proofing, it might as well be in the shower. Water will pass right through that assembly and end up in the walls and the equipment. This is why TCNA standards require vapor impermeability membranes be no more than .5 perms for a steam shower. That build assembly is not built correctly and will not even work for a regular plain water shower. Much less a steam shower. You need a 100% rebuild from a more qualified tile contractor. 100% rebuild. Someone who has is familiar with TCNA standards, and preferably CTI designated.

https://www.tcnatile.com/products-and-services/publications/218-english-publications/188-handbook/968-2020-tcna-handbook-for-ceramic-glass-and-stone-tile-installation.html

I think you need to go back and get an actual steam shower pro to do this or get a prefab steam shower this is not going to be a steam shower maybe even not a regular shower. This is a casr of you don’t know what you don’t know.

I am wondering if this is just a situation where the Tiler should have built the mudpan smaller so that the bench was built behind it off the floor and is now trying to get out of fixing it by scaring me to move away from the steam shower.

Was the bench always in your plans or added when you decided to change to a steam shower? Even if you don't do the steam shower, I wouldn't want the mudpan to continue under the bench. What is supposed to stop the water from seeping under the bench?

Were your plans permitted and was the work inspected? That is really the purpose of the permit and inspection process - making sure people don't do things that are unsafe and/or non-compliant with current code standards.

Not only do I believe that is out of code another reason not to put it in the shower or actual bath is they are really loud. Attics or insulated closets are the usual locations for the steam generators. My non steam shower stall with proper water proofing, labor to tile and glass door cost almost 10K my quotes to do a vapor proof steam shower with materials and labor was double that.

The generator can be under the bench, but the water- and vapor-proofing that go on the shower ceiling, walls, bench surfaces, and floor, should completely isolate the generator from the shower space.

It's better to use a surface applied membrane in a steam shower. It limits vapor drive deep into the shower surfaces. Example, your floor has an Oatey membrane. The floor mud could have been isolated from moisture and vapor by using a surface applied membrane.

If the generator is simply an after-the-fact add-on, consider rethinking a few things and starting over. Right now, when your mud floor saturates, moisture will migrate under the bench via capillary action. It could get messy under there.

Have you thought through your steam vent location. If you're sitting on your bench with your feet on the floor, a blast of steam out of the walls and right on your lower legs will be neither soothing nor relaxing.

Consider:

1) Breaking up the floor. Stop the floor mud from being continuous, covering both the shower floor and the floor under the bench. The mud under the floor will saturate the way it is currently laid out.

2) Insulative value in the walls and ceiling can improve steamer performance. The less there is to heat up, the more steam you get and the less condenses out of atmosphere. Think along the lines that the walls will not be a heat sink. With insulation behind the tile, once the tile warms, the wall is warm versus heat passing through the tile and conducting in to the thickness of wall.

3) As has been mentioned, consider a surface applied membrane that is not just a waterproofing membrane, but a vapor-proof membrane as well. If your installer was going to til right over that backer board, with inadequate drying cycles, the steam generator will drive moisture through the grout and backer board, into those framing bays. they'll accumulate moisture over time until failure becomes apparent.

4) Imagine sitting on the bench, and imagine if the steam coming out of the vent will hit your legs, or not.

These may all sound like negatives. But do understand that a step backward to make things right can be a HUGE step forward. If I'm not understanding your build and you've already figured these issues out, then no worries.

Aside from all of the very real concerns listed already, how will that unit ever be serviced or removed if it fails? It looks like it would be fairly inaccessible without removing tearing out the bench. This location has so many warning bells going off. Please reconsider.

That is not an industry acceptable build. It needs to be redone.