Caulking around Beveled Tile in Steam Shower

[pie]

Hello all, I purchased a new home where the builder used beveled tile in the steam shower (tiles have beveled edges on all sides - see pic). The shower fixture trim pieces have gaps due to the beveled edges and I'm worried water will get behind the cement board and into the walls, especially because it is a steam shower. I've asked the builder to silicone caulk around the trim and on the advice of their plumber they caulked some of the gaps (gaps at the top of fixtures) but left the ones at the bottom untouched as they said the gaps would be needed to let water out should it ever get in. Should all the gaps be caulked? I'm assuming if all the gaps are caulked there would be no need to "let water out". Any advice is much appreciated.

https://imgur.com/a/29A0yOF

 

[Jadnashua]

The water and steam protection in a shower is NOT the tile...it's whatever is beneath the tile. So, if the shower was built to industry standards, you only need to protect around the trim from liquid water, and it's common to leave a gap below to let any that might get there to weep out.

Building a steam shower is a very exacting procedure, and it is often not done properly. It's not particularly hard, but must be done VERY carefully to work right long-term.

While cement board is a common backer, for steam shower use, there must be some waterproofing that also has a low perm rating on top of it, and that should be sealed around any penetrations prior to the tile being installed. That waterproofing, again, is NOT the tile...it's either a liquid product approved for steam shower use, or a tileable sheet membrane. Cement board is also NOT waterproof, but it is not damaged by being wetted. STeam will try to penetrate, and that must be stopped to protect the structure.

 

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[pie]

I have exactly zero experience with steam showers so I appreciate and thank you for your views Jim. So you are saying the waterproofing membrane for the shower (if done properly) would have sealed the gap around the holes where the shower fixtures protrude before the tile was put on?

 

[Jadnashua]

It is important to make the enclosure vapor and water tight prior to installing the tile, so, yes, the shower SHOULD be protected from moisture getting inside the structure around it. Sealing around the trim to the tile is important, but it's common to leave a gap at the bottom.

Now, without knowing how the shower was actually built, cannot say how well it will perform long-term.

It looks like that tile is glazed. Depending on the type of ceramic (bisque or porcelain), that may not be a great choice for a steam shower. The best tile for a steam shower is probably a through-body, unglazed porcelain tile. Porcelain tile absorbs moisture at a very low percentage point (typically, less than 0.25%). A bisque tile can absorb as much as 30%, even with a glaze on it!

 

[pie]

Yes the tile is glazed. Have no idea what type of tile it is though. Thanks for your thoughts.