With the permit in hand and the crew ready, it is natural to wonder what stands between you and move-in day. The short answer is a series of DADU building inspections, plus separate finals for each trade permit. A DADU, or detached accessory dwelling unit, is a separate home on the same lot as a house. Nobody can live in it without approval to occupy from SDCI, which follows a passed building final.

Details below reflect official Seattle pages checked in October 2026. Confirm with city staff for your property.

Who Schedules Each Visit?

You do, or the builder does for you. SDCI says the permit holder is responsible for requesting each inspection. Requests go through the Seattle Services Portal online or the city’s automated inspection line, using the permit number.

An inspector visits and either approves the work or lists items to fix. If something fails, the crew corrects it and asks for another visit. SDCI notes that inspectors can repeat most inspection types. A failed visit is a delay, not a dead end.

What Comes Before Framing?

Work on the ground starts the list. SDCI’s construction inspections page names a site inspection before the first ground disturbance, tied to erosion control. Some projects need a first ground or preconstruction meeting ahead of any digging.

The foundation inspection follows, ahead of any concrete pour. Inspectors look at forms, rebar and footing locations while changes are easy. The post on DADU site work costs explains why this early stage carries so much risk on many lots.

Framing, Structure and Mechanical Work

Once the floor framing is in, a subfloor inspection comes before anyone covers it. A structural inspection checks the frame ahead of outside sheathing. SDCI’s residential quick sheets add a mechanical cover inspection ahead of any insulation or wall cover.

The framing inspection takes place ahead of insulation. Walls close soon after, so open items need fixing right away. Ducts, vents and blocking should be ready early.

Insulation and the Energy Details

Next comes the insulation inspection, once insulation is in but ahead of drywall. An inspector compares what is in the walls, floors and ceilings with the energy details in the approved set.

This visit ties back to plan review. Values the reviewer approved now have to show up in the real building. The overview of the Seattle DADU review covers how reviewers check those values on paper. If drywall goes up early, the inspector may not be able to see the work.

Do Trade Permits Have Their Own Inspections?

Yes. SDCI states that mechanical, refrigeration, electrical, plumbing, side sewer and water work need separate permits and separate inspections. Each one runs on its own track beside the building permit.

• Electrical wiring, inspected by SDCI under the electrical permit.
• Plumbing and gas piping, inspected by Public Health Seattle and King County.
• Mechanical systems, with cover and final visits listed in SDCI’s quick sheets.
• Side sewer and water service, handled through Seattle Public Utilities.

Most trades have a rough stage and a final stage that need to line up with the building schedule. The post on DADU utility expenses explains why these connections often take extra coordination.

When Does the Building Final Happen?

Last on the list is the building final. SDCI performs it after all construction is complete and after every related permit has received its own final inspection. Any required special inspection reports need to reach the city as well.

So one missing trade final can hold up the whole cottage. A unit can look finished for weeks with one small item still open.

Finished, Inspected and Approved Are Not the Same

Three ideas tend to blur together. Construction completion means the crew has finished. Passed inspections mean each inspector signed off on their part. Approval to occupy is the only one that lets someone move in.

For single family homes and duplexes, the city issues that approval after the final inspection. Other project types may need a Certificate of Occupancy instead. Ask the city which applies to your permit before you plan a move-in date.

A Hypothetical Wallingford Cottage

Picture an invented Wallingford lot with an alley, a two story cottage and a heat pump. The builder plans the work around inspection points, not calendar dates. Each of the DADU building inspections gets its own line, with a short buffer behind it.

The framing passes, but the mechanical cover inspection notes a missing duct strap. A crew member fixes it the same afternoon and requests a second visit. Later, the building final waits on the electrical final, which is why the owner treats the move-in date as a target rather than a promise.

Common Inspection Surprises

These issues show up on many cottage projects.

• Walls closed ahead of the insulation or cover inspection.
• A trade final that lags behind the building final.
• Erosion control measures missing at the first site visit.
• Special inspection reports that never reach SDCI.
• Field changes that do not match the approved plans.

Frequently Asked Questions

Does every DADU get the same inspections?

No. SDCI lists the inspections that may be required, and the exact set depends on the design and the permits. A cottage with special structural work, for example, can add preconstruction meetings that a simple plan never needs. Your permit record shows what applies.

Can someone move in after the last trade final?

Not yet. The building final still has to pass, and approval to occupy follows it. Trade finals are steps toward that point, not a substitute for it. Plan any move or lease start around the building final, with time for a possible second visit.

Should inspection records be kept?

Yes, keeping them in one folder is a good habit. Lenders, insurers and future buyers sometimes ask for proof that the work passed. The portal record holds most of this, but your own copies help when a question comes up years later.

Before Construction Starts

• Ask the builder for a list of expected inspections.
• Note which trade finals must clear ahead of the building final.
• Read the SDCI quick sheet for each stage ahead of time.
• Set up portal access so you can follow results.
• Agree on who requests each visit.

The cottage is not ready until approval to occupy is granted, no matter how finished it looks. Track every trade final alongside the building permit and use SDCI’s construction inspections page for the current list. More on DADU permit requirements sits in the permits and approvals section.