Tenant Build-Out Plumbing Timeline: What to Expect

Weeks 1-2: Permitting and submittals

Drawings go to the jurisdiction and fixture submittals go to the architect at the same time. Review timelines differ significantly between St. Louis City, St. Louis County, and the St. Charles County municipalities — build that variance into your schedule rather than assuming the fastest case.

Weeks 2-4: Demo and underground

If the new layout moves a restroom core or adds a sink island, slab gets cut. Underground sanitary and vent go in, get inspected, and get backfilled before concrete patch. This is the single most schedule-sensitive step in the job — an inspection miss here pushes everything.

Weeks 4-7: Overhead rough-in

Waste, vent, and domestic water run above ceiling, coordinated with HVAC and electrical. In an occupied building this is where after-hours work usually happens, because branch tie-ins require water shutdowns on floors that are still leased.

Where occupied-building jobs slip

• Shutdown windows approved late by property management
• Existing conditions that don't match the as-builts
• Ceiling access limited by tenant hours

Weeks 7-9: Fixtures, trim, and final

Fixtures set after flooring and casework. Water heater, backflow, and any auto-flush controls get started and tested. Final inspection and backflow certification close the plumbing scope out.

How to protect the schedule

Release long-lead fixtures at permit submittal, not at rough-in. Get shutdown windows approved in writing before overhead starts. And walk the existing conditions with your plumbing contractor before the bid is locked, so surprises become scope instead of change orders.