We recently completed a renovation in a locker room at a local condominium complex. We removed the old flooring and ceramic tile in the shower area. We installed 12″x12″ porcelain tile on the floor and shower walls. We removed the existing concrete slab in the showers, poured a new concrete floor pitching towards the drains. This eliminated the need for curbs to step over when entering the shower. We then installed 2″x2″ ceramic tile on the floor.
All said and done with a natural grout and matching caulk.