The inspections
SDCI inspects at multiple stages during the build:
- Foundation — before the pour.
- Framing — before insulation.
- Sheathing nailing — if shear panels.
- Electrical rough — by SDCI.
- Plumbing rough — by King County Public Health.
- Mechanical rough — by SDCI.
- Insulation — before drywall.
- Final — at substantial completion (drives Certificate of Occupancy in step 6.2).
Each inspection has to pass before the next stage starts. A failed inspection on Friday is a Monday-or-later re-inspection — and that delay cascades.
The required tests
Two energy-related tests are required by the Seattle Energy Code (SEC):
- Blower-door test — measures air leakage at 50 Pa pressure. Limit: ≤5 ACH50 (or 0.4 cfm/sf alt for attached).
- Duct-leakage test — if the system has ducts. Limit: ≤4 CFM25 per 100 sf.
A specialist with calibrated equipment runs the tests, usually after drywall and air sealing but before final finishes. Costs:
- Blower-door: $300 – $600.
- Duct leakage: $250 – $450.
If a test fails, the GC finds and fixes the air leaks, then retests. A failure that requires opening up walls is the worst case.
Why this is its own step
Inspections and tests punctuate the entire build, but they're not "a phase." They're the checkpoints between phases. Treating them as a single workflow step lets you track one clear deliverable (passing reports and sign-offs ready for CofO) without cluttering the build steps with inspection bookkeeping.
Where this information came from
- SDCI Tip 116B — Establishing a DADU · retrieved April 22, 2026
- Building Connections — Side sewer transfer to SPU · retrieved April 22, 2026
- King County Wastewater Capacity Charge · retrieved April 22, 2026
- L&I Verify a Contractor · retrieved April 22, 2026