tiling a surface that will be underwater

[WolfSterling]

If you are tiling a surface that will be permanently under water, say a pool or hot tub, is it best to use thinset and then seal it or do you use some other kind of grout? I don't know the procedure for tile that will permanently underwater.

Also, what kind of tile would you use? Would it have to be impervious tile?

[Davy]

I would look for a porcelain tile, it's about as tuff as they get. Most pool tiles are porcelain, they will work fine. Also would use a good modified thinset, something like Custom Flexbond. Give the thinset plenty of time to set behind the porcelain and it'll be fine. Burn in a skim coat on the substrate and also on the tiles as you set them. I'd also use epoxy grout.

[Jim Farrell Tiler]

i dont know about where you are but lots of the adhesives have on the bag " not suitable for continous immersion so make shure you get a adhesive that is

[poolmaninct]

2 to 1

cement to marble dust is an exceptional underwater grout.

aka marcite, requires to cure under water, ill post some links when i get a chance


ray

[nforcer2]

LATICRETE 254 Platinum is rated for constant submersion.

[Chris the Rep]

The most commonly tiled pools are referred to as competitive pools; like what you'd find in a high school or college natatorium. These are almost always
1 x 1 mosaics, porcelain or highly vitrified. As an aside, this size is used because of the critical dimensions required for these types of pools.

However, I'm going to disagree with Davy on both counts. I would not use modified thin-set or epoxy grout in continuous immersion. Robert (Nforcer2) points out that Laticrete 254 is suitable for underwater applications. I'd guess that this is one of the few modified thin-sets that are acceptable in immersion applications.

Otherwise, a high quality unmodified thin-set will do fine. If you feel that you need latex, use the same manufacturers' liquid latex admix if they'll approve it for underwater.

I can't speak to using marcite, I'll defer to poolman's expertise there. But most pools I've ever seen were grouted with the good old job mixed sand and cement at 1:1 ratio.

Chris