Scope Creep at the Coffee-Shop Rough-In: Permit Revisions and Concealed Work
A plumbing contractor holds the permit for a tenant build-out converting a 2,400-square-foot retail space into a coffee shop with a limited menu. The approved plumbing sheets show a three-compartment sink, two hand sinks, a mop sink, three floor sinks, a 50-gallon gas water heater, and a 1,000-gallon exterior grease interceptor. At the rough-in inspection the inspector finds: (1) a 2-inch gas line and shutoff run to a 250,000 Btu/h combi oven that appears on the equipment schedule but not on the approved gas riser diagram; (2) a toilet and lavatory framed into a former storage closet that was not on the approved plans; (3) the water heater moved 8 feet from its approved location with its vent re-routed; and (4) the under-slab drainage already covered with 4 inches of concrete. The general contractor tells the plumber to "keep going, we'll fix the paperwork at final." The plumber's contract does not address permit revisions.
1. What is the correct sequence for handling the three field changes, and what are the specific risks of following the general contractor's instruction?
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The permit defines the approved scope. An inspector can only approve what is on the approved drawings, so items 1 through 3 are scope changes, not paperwork. The correct sequence:
- Stop work on the affected items - particularly the gas line to the combi oven and the relocated water heater vent. Neither can be concealed or energized on an unapproved drawing.
- Submit revised plans (gas riser diagram showing the added load; floor plan showing the new restroom and its venting; revised water heater location and vent route) and pay the revision fee.
- Obtain the amended permit and request inspection of the exposed work.
Risks of "fix it at final": the AHJ can issue a stop-work order, refuse a final inspection, and require the covered under-slab drainage to be broken out and re-tested at the plumber's cost. The permit holder - not the GC - is the party of record for code compliance, so a verbal instruction from the GC does not transfer liability. If the plumber proceeds, an administrative penalty or a license complaint can follow, and the extra work is often unrecoverable without a written change order. Get the direction in writing before doing anything beyond the approved scope.
2. Setting the permit issue aside, what code and design questions does the 250,000 Btu/h combi oven raise for the plumbing contractor?
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Adding 250,000 Btu/h is a gas-piping redesign, not a branch tee. The plumber must:
- Recalculate the gas load using the longest-run method with the new total connected load, and verify the meter and service regulator capacity, not just the pipe size. A 2-inch branch is meaningless if the main or meter is now undersized.
- Confirm appliance requirements: a sediment trap, a listed connector, a shutoff valve in the same room and within the code's distance limit from the appliance (commonly 6 feet), and clearances to combustibles.
- Resolve venting and combustion air for the appliance per its listing category and the manufacturer's instructions. A high-input combi oven in a small tenant space often needs its own exhaust hood or direct vent, and that decision belongs to the mechanical designer, not the plumber in the field.
- Check whether the equipment schedule's appliance is the same model the gas diagram was based on; input ratings and vent categories frequently change between design and procurement.
None of this can be resolved by the plumber alone, which is why the revised drawings must come from the designer of record before the gas line is connected or the appliance energized.
3. The under-slab drainage is already covered. What testing and documentation should the plumber have completed, and what are the options now?
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Drainage piping must be tested and inspected before concealment. Depending on the adopted code, that is typically a water test with a 10-foot head of water (or the code's specified pressure) held for the required duration, or an air test at the code's specified pressure, with all joints, fittings, and the building drain visible to the inspector.
Because the slab is poured, the plumber's options are limited and should be presented honestly to the owner:
- Expose and re-test: break out the concrete over the affected runs, test, and call for inspection. This is the most defensible path and the most expensive.
- Request AHJ acceptance of an alternative: some jurisdictions will accept a documented special inspection, a video inspection, or a written variance, but only if the AHJ grants it in advance. Photographs alone do not substitute for an inspection unless the AHJ has a written policy allowing them.
Either way, the plumber should document the sequence in writing, notify the GC that the concrete was placed before inspection, and secure a change order before opening the slab. Proceeding to final without resolving it risks a failed final inspection and a certificate-of-occupancy delay that dwarfs the cost of the test.