What inspections are required during a garage conversion?

A garage conversion is inspected at the same key construction milestones as any ADU, with a few conversion-specific checks built in — most notably the under-slab plumbing and the framed-in garage door opening. Inspectors compare the installed work against your approved MEP plans at each stage, which is exactly why complete, accurate plans keep inspections clean. The exact sequence and naming vary by jurisdiction; confirm with your local building department.

The typical inspection sequence

The conversion-specific checkpoints

• Under-slab plumbing — because the garage slab has no below-grade drainage, the new DWV must be inspected in the open trench before the slab is patched. Missing this window means re-opening the slab.
• Framed door opening — the closed opening is checked at framing and insulation like any exterior wall, including egress and outlet spacing.
• Ventilation — the ASHRAE 62.2 system that replaces the lost door-gap airflow is verified at rough mechanical and final.

The Title 24 verification layer

Beyond the building inspections, the energy code adds its own paper chain. Installing contractors complete CF2R certificates confirming the work matches the CF1R, and where HERS verification applies — refrigerant charge on the new heat pump, for example — a certified HERS rater field-tests and registers a CF3R. The certificate of occupancy isn't issued until the required CF3Rs are registered, so line up your HERS rater early.

Inspectors check the installed work against the approved plans, so any field change should be reflected on the drawings to avoid a failed inspection. Requirements and inspection naming vary by jurisdiction; confirm with your local building department.

The most important sequencing rule on a conversion is that several systems must be inspected before they're buried — the under-slab plumbing before the concrete is patched, and the rough electrical and mechanical before insulation and drywall close the walls. Scheduling those inspections in order, and not covering work until each one passes, is what prevents the most expensive setback of all: tearing out finished work to expose something an inspector never signed off on.

The through-line is that every inspection references your plans. Complete, coordinated MEP plans with the under-slab DWV, ventilation, and firestop details shown up front are what let each inspection pass the first time. Start your order or see how it works.