Let us tell you some basics about the recommended construction of steam rooms:
These cabins should be insulated very well, of course steam-proof and, nevertheless, well exhausted; it should be forbidden to build with mortar or concrete which is simply tiled afterwards. Unfortunately it is done like this often to build very cheap.
The seats should be heated and be tiled hygienically. Have a look, for example, at the single seat illustrated on the right here: it is tiled with only four ergonomically formed ceramics; indeed, this is expensive, but from unmatched hygiene and perfect seat comfort!
Last the steam outlet must be build in a way so that nobody can injure itself. Also here we use especially formed elements to fulfil this demand!