Bathroom rough-in plumbing

Rough-in plumbing is everything that happens between demolition and the first sheet of drywall: copper or PEX supply lines, ABS drain lines, venting brought up to the new layout, and the exact placement of stub-outs for the sink, shower, toilet and sometimes the washer.

Every stub-out is set to the final fixture plan, not the old bathroom's layout — most site surprises trace back to a mismatch between the plumber and the tiler. We coordinate measurements with your contractor before anything is run.

Everything is pressure-tested and photographed before the walls close, so the inspection and the drywall can follow without having to backtrack.

Floor type sets how much room there is to line new fixtures up with the layout. In a house or a plex with wood joists, each drain has to land inside a single joist bay with enough slope to reach the stack, which limits how far a shower or sink can shift from its old spot. In a condo tower, the floor is a concrete slab and the drains are usually cast into it; enlarging or reorienting the bathroom means opening the slab, not just the wall. Venting has to be resized for the whole new fixture group even when nothing moves, because an under-vented system shows up later as traps that siphon dry and odours that come back up the drain.

Trade sequencing matters as much as where the lines run. Rough-in plumbing follows demolition and comes before insulation and drywall; an electrician who drills or nails into the same joist bay as a drain before the plumber is finished usually creates a conflict that only surfaces at inspection. Once the drywall is up, opening a wall to fix a misplaced stub-out means redoing a section of tile or paint, not just plumbing. That's why the pre-close inspection isn't a formality — it confirms slope, pipe sizes and venting are correct before the rest of the job moves forward.

In a condo, some of these lines tie into the shared riser that also serves neighbouring units. Shutting the water to connect a new stub-out can shut off supply to several units at once, which means advance notice to the syndicate and usually a specific window under the building's rules — noisy work on weekdays only, within set hours. The plumber needs to build that coordination into the schedule rather than discover it on the day, or the job sits waiting for access that wasn't requested in time.

The price of a full rough-in mostly tracks the number of fixtures served, the distance to the existing stack, and whether the walls are opened to the studs or rebuilt outright. Fixture choices — shower valve position, toilet drain height, sink centreline — need to be locked in before this stage: those are exact measurements specific to each model, and changing them once the drywall and tile are on costs far more than confirming them at the planning stage.

The choice between copper and PEX comes down mostly to what's already in the building, not a general preference. A plex fed with copper usually keeps copper at the riser connection even if PEX runs through the walls from there, because mixing materials at the wrong point creates a weak spot over time. When the bathroom backs onto an existing heated floor, the position of the heating loops needs to be known before water lines are run, so a drain or wall stub-out doesn't puncture a loop hidden in the slab. Individual shutoff valves are also set for each fixture during the rough-in — a small detail, but one that avoids shutting off water to the whole floor for future maintenance, which matters especially in a plex or multi-unit building where cutting the water affects more than one household.