Phase 1 — UNDERGROUND: Install below-slab plumbing (building drain, waste, vent stubs) before slab pour. Electrical conduit in/under slab. Verify locations against plan. Test DWV (air or water test). HOLD POINT: underground inspection before slab pour. Phase 2 — ROUGH-IN: After framing, before insulation. Order of work: plumbing first (least flexible), then HVAC (largest pathways), then electrical (most flexible). Drill/notch per code limits. Fire-stop all penetrations through rated assemblies. Phase 3 — TEST: Plumbing DWV air test (5 psi / 15 min). Supply pressure test (water test per code). HVAC duct leakage test (if required). Electrical: verify circuits, grounding, AFCI/GFCI. HOLD POINT: rough inspection (all trades) — inspector verifies code compliance before walls close. Phase 4 — INSULATE: After rough passes. Batt, blown, or spray foam per energy code. Vapor barrier per climate zone. Phase 5 — CLOSE: Hang drywall. After this point, MEP changes require cutting and patching. Critical coordination: all rough work COMPLETE before calling inspection.