Locate penetrations before the membrane closes
The scope should say which pipes, valves, shower heads, and glass clamps will pass through the tiled face, and it should put those locations in place before the waterproofing layer is completed. A membrane that is already finished cannot be redesigned around a fitting that arrives later. The tile lines do not silently include moving those fittings.
List every hole
Walk the wet wall and write each penetration: the valve, the spout, the head, the hand-shower bracket, the glass clamps, and any grab bar. Give a height from the finished floor or from a fixed point that will still exist after the old finish comes off. A list that says plumbing belongs to others, without locations, leaves the membrane crew guessing where to leave the seals.
Order relative to the membrane
The scope should state the order: blocking and rough locations first, membrane continuous around those locations, tile after the membrane is complete, trim and glass after the tile. If a fitting must be installed in a different order, that exception needs its own sentence. An unstated order is how a hole gets cut in a finished membrane for a bracket nobody listed.
Glass and bars are penetrations too
A clamp or a grab bar that lands after tile still needs blocking and a sealed passage. Treating glass as a later decoration forgets that the fastener crosses the waterproofing. If the glass layout is undecided, the scope should say the membrane will not be treated as complete until the clamp locations are marked. Undecided glass is a hold on the wet assembly, not a leftover task.
Related Costa Tile Works services: Shower tile installation. See all services, service areas, and all guides.