ROUGH-IN PLUMBING
Commercial rough-in plumbing contractor
THE STAGE THAT DECIDES THE JOB
Everything after rough-in is finish work
Rough-in covers all the piping that ends up buried: under the slab, in the walls, above the ceiling. Once concrete is poured and drywall is hung, changing any of it means demolition, so rough-in is where accuracy is worth more than speed.
The work splits into two blocks. Underground rough-in is sanitary and vent piping set to grade beneath the slab, which has to be inspected and backfilled before the pour. Above-slab rough-in is waste, vent, water and gas run through walls and ceilings, which has to be tested and inspected before the walls close.
Both blocks are hold points on the schedule, and both are inspected. We build the dimensional layout off the fixture and equipment plan, verify it against the architectural dimensions, and mark the deck before we cut, because a fixture that lands two inches off a carrier is a wall that comes back apart.
What rough-in includes
- Layout and marking from the fixture and equipment plan
- Saw cutting, trenching and shoring where required
- Sanitary and vent set to grade with correct fall
- Cleanouts placed to stay accessible after finishes
- Water, gas and waste risers through walls and ceilings
- Hydrostatic or air testing with the inspector present
ROUGH-IN WORK
What we install at rough-in
Dimensional layout
Fixture and equipment centerlines transferred from the drawings to the slab and the framing, checked against architectural dimensions before anything is cut.
Underground sanitary and vent
Trenched, bedded and set to grade with the required fall, joints made up and supported, then tested, inspected and backfilled ahead of the pour.
In-wall waste and vent
Stacks, branch waste, vents and carriers set in the framing at the right height and depth for the specified fixtures and the finished wall thickness.
Water piping
Hot, cold and recirculated water run through walls and above ceiling, supported and sleeved correctly, with isolation valves where they can actually be reached later.
Gas rough-in
Black iron or approved piping from the meter to the equipment locations, supported and sealed, then pressure-tested for the duration the jurisdiction requires.
Testing and inspection
Air or hydrostatic testing held at pressure for the inspection, with the test results and the sign-off documented for the closeout package.
THE TWO GATES
How rough-in is sequenced
01
Verify before you cut
02
Underground installation
03
Underground test and inspection
04
Above-slab rough-in
05
Rough-in test and inspection
06
Protect and hand over
COMMON QUESTIONS
Rough-in plumbing questions
Underground rough-in is the sanitary and vent piping beneath the slab, installed and inspected before the concrete is poured. Above-slab rough-in is everything in the walls and ceiling — waste, vent, water and gas — installed and inspected before drywall. They are separate inspections and separate schedule gates.
By scanning first. We locate post-tension cables, rebar and embedded conduit with ground-penetrating radar or equivalent before any saw cutting, and we mark and document what we find. On post-tensioned slabs this is not optional.
The work is corrected and re-inspected, which costs days rather than hours because inspection slots are scheduled. That is why we pre-test everything ourselves and walk the rough-in against the drawings before we call for the inspection.
No. Underground and rough-in are both inspected work, and installing them without an issued permit risks having to open up finished work later. We use the permit window to release long-lead equipment and complete layout instead.
From the applicable accessibility standard and the specified fixture’s rough-in dimensions, measured to the finished floor and finished wall rather than to the substrate. Getting this wrong is one of the most common causes of a failed final inspection.