An epoxy can be used as a tile fixing or tile grouting solution although often only used as a tile grout due to it's high costs. the advantage of using epoxy as a grout is the pure fact that it's impervious to not only water, many chemicals can also not work it's way through the epoxy once cured. This allows it to be used in Food Preparation areas such as commercial kitchens and the likes. Using an epoxy as a grout in a shower environment will also ensure your shower will not leak to any floors below it providing other methods of tanking are carried out to enforce the epoxy.
A good make that's easy to apply and clean off is one manufactured by Mapei.
A good make that's easy to apply and clean off is one manufactured by Mapei.