Rough-In
The phase of construction where plumbing, electrical, and HVAC systems are installed inside walls before drywall is hung.
Rough-in work refers to the installation of mechanical, electrical, and plumbing (MEP) systems inside the wall, floor, and ceiling cavities before those cavities are closed with drywall or other finishes. Plumbing rough-in includes supply pipes, drain lines, and vent stacks stubbed to the planned fixture locations. Electrical rough-in includes running wire, installing boxes, and landing conductors at panels. HVAC rough-in includes ductwork, refrigerant lines, and equipment rough-mounting.
All rough-in work must be inspected and approved by the building department before drywall is installed, because closing the walls buries the work and makes inspection impossible without destructive access. The rough-in inspection is one of the most important hold points in any renovation.
Rough-in costs are typically a significant portion of total MEP budgets—often 40–60%—because the hidden infrastructure is labor-intensive. Trim-out (installing fixtures, outlets, switches, and registers) comes later and is usually faster per unit.
Real-World Example
The plumber completed rough-in for the new second-floor bathroom in two days, stubbing out hot and cold supply lines and a 3-inch drain before the framing inspection.