Build the Seattle ADU Approval File Around the Property

Seattle’s Department of Construction and Inspections, or SDCI, reviews projects inside Seattle. A property outside city limits uses another city or King County process. Check the boundary first because it controls the forms, code and office in charge.

Start with a written site brief

Before asking for plans, make a short site record. Include the address, lot size, current buildings, slopes, large trees, access and utilities. Add any records already found. State the owner’s goals for the unit, rooms, access, privacy, parking, finishes and budget.

This brief lets designers explain what they know and what remains an assumption. It also prevents three companies from solving three different versions of the project.

Assign the review work

Not every lot needs every expert. The team should decide whether it needs a boundary or slope survey, tree report, soil study or structural review. Drainage and utility locating may also be needed. Work in the current house may require opening a hidden area.

For each review, record:

• who orders it and owns the resulting file.
• whether the quoted design fee includes it.
• when the result must arrive to protect the schedule.
• which design choices depend on it.
• what happens if the finding changes the concept.

Property check review should resolve the biggest questions before detailed drawing time accumulates.

Understand the layers in a permit filing

A Seattle filing may need several types of plans. The exact list depends on the project. Expect the team to cover the site, building, structure, energy use and systems. A detached unit may also need grade, drainage and foundation details. A conversion needs clear plans of current conditions.

The file may include current and planned site drawings, floor plans and outside views. It may also include sections, structural details, energy records and equipment notes. The number of sheets matters less than whether they agree.

Use SDCI’s current accessory dwelling unit guidance as the official starting point. A company should cite the live rule it used rather than presenting an old checklist as universal.

Choose a team with clear handoffs

The salesperson may not prepare or stamp the plans. Ask for the names and roles of the designer, architect, engineer, energy expert and permit lead. If the builder hires an expert, check whether the owner can use that work with another builder.

The design agreement should list plan options, meetings, site visits and owner change rounds. It should cover replies to City comments and support during construction. Also list what is outside the fee. “Permit help included” is not enough.

Treat pre-approved DADU plans accurately

Seattle’s ADUniverse includes DADU designs that have received advance review for recurring portions of the design. That can reduce repeated design effort for a compatible project. It does not turn an arbitrary lot into an approved building site. Placement, zoning, foundation conditions, drainage, utilities and other property matters remain site work.

Before selecting one, overlay its true footprint, entries, windows and required working room on the site. Price adaptations separately. Compare that result with a purpose-designed option using the standard-plan choice guide.

Manage SDCI review as a tracked workflow

A filing can move through intake, review, corrections and a new submission. Ask the permit lead to track dates, City comments, the person responsible and the next task. Keep City review time separate from time waiting on the owner or design team.

Nobody outside SDCI can guarantee the permit date. A useful schedule shows which steps depend on others and changes when new facts arrive. See the Seattle ADU timeline for the full order.

Freeze a pricing set

Quotes can be compared only when they use the same dated plans. Before bidding, make a price set and list of assumptions. Cover finishes, fixtures, appliances, utility routes, outside repairs and owner-bought items. Use the Seattle ADU cost guide to keep the owner-paid items visible.

If review changes the project, circulate a revision notice and ask each bidder to acknowledge it. Otherwise an apparently low number may simply belong to an obsolete design.

Convert issuance into a field-ready package

A permit is a milestone, not the end of planning. The owner should receive the issued plans, conditions, permit record and inspection details. Add any plans due later and open utility tasks. The builder should confirm that its price matches that exact set.

Keep one controlled digital folder. Superseded drawings should be visibly marked so they do not reach the job site. During building, record approved changes and inspection outcomes in the same file.

Questions to put in the design quote

• Which city or county and permit route have you assumed?
• What site details are confirmed, and what is provisional?
• Which consultants contract with me directly?
• How many concepts and owner revisions are included?
• Who submits, monitors and answers SDCI comments?
• Are ordinary correction responses included in the fee?
• What work continues after permit issuance?
• May I use the documents with another licensed contractor?

Written answers expose work differences much earlier than comparing a single design-price total.