Plumbing Notes/remodel
Bathroom rough-in + remodel plumbing
A bathroom remodel lives or dies at rough-in, before any tile goes up. Here's what our crew sets behind the wall on Inland Empire jobs, and what we end up replacing.
By Brad Staiger — Staiger Plumbing, LIC. #802197
What rough-in actually is
When we open a bathroom wall for a remodel, the rough-in is everything you won't see once the tile is up. The shower valve body, the PEX-A supply lines feeding it, the drain below, and the waterproofed pan underneath. We set the valve at the right height and depth for the finished wall thickness, pressure-test the supply, and confirm the pan holds water before anyone tiles over it. Get any of that wrong and you are opening a finished wall later to fix it. In older Inland Empire tracts around Fontana and Rialto, we are usually tying new PEX-A into whatever is left of the original galvanized or copper, so the rough-in is also where we decide how far back the good pipe actually starts. The open cavity is the one honest look you get before everything closes up.
What's under the old tile
Almost every remodel where we pull the toilet, the flange tells the real story. We have lifted tile in Ontario and Chino and found the flange rusted thin, the wax ring blown out, and the subfloor stained dark from years of slow seepage nobody caught. Hard Inland Empire water and a wax seal that flattened out a decade ago will do that. A toilet that rocked even slightly kept breaking the seal, and the leak went down into the floor instead of the bowl. At rough-in we cut back to sound subfloor, set a new flange flush to the finished tile height, and tie it to the drain the right way. Doing it now, with the floor already open, costs a fraction of doing it after the new tile is down and grouted.
Setting drain and vent
On a ground-up bath or an addition, we run new ABS drain and vent through the floor framing before the walls close up. The work looks like black ABS set through the joists and foam-sealed into the subfloor opening, with the vent carried up so the trap actually breathes. A drain that doesn't vent right will gurgle and pull the trap dry, and you smell it months later when the water seal is gone. We slope the drain a quarter inch per foot and check it, no guessing by eye. In the newer Murrieta and Menifee tracts where slab and framing are both in play, we coordinate the under-floor runs with the framer so nothing gets boxed in where we can't service it. Drainage and pressure both get verified before any insulation goes in.
Stub-outs, niches, and the finish wall
Once the rough plumbing passes, the tile crew can set stub-outs and niches knowing nothing behind them will move. We have set dual recessed niches and a black matte shower valve on jobs where the homeowner picked the trim before we even roughed in. That matters, because the valve body has to match the trim kit and sit at the right depth for the finished tile and backerboard. Inland Empire basin pressure runs high in a lot of neighborhoods, so we will often flag a pressure check while the wall is open, since a remodel is the easy moment to add or service a pressure-reducing valve before everything closes. The stub-out height for the shower head and the valve get set to the finished surface, not the bare framing, so the trim lands flush later.
Setting the tub and closing up
The last big rough-in piece is usually the tub. We dry-fit the alcove tub against the framing, set it level, and connect the waste and overflow before the surround goes on, because once that wall is tiled the connections are buried for good. Clay soil out in Norco and Chino Hills shifts framing more than people expect, so we shim and secure the tub so it isn't riding on the drain line. After that it is trim-out. Faucets, the toilet on its new flange, the shower trim on the valve we set weeks earlier. What all of this means for you is simple. The rough-in is the part of a remodel you never see and the part that decides whether the finished bathroom holds up. Set it right with the wall open, and the tile work in front of it lasts.