Seattle Faster Path
Seattle pre-approved DADU plans.
The faster legal path to a finished DADU inside Seattle. Skip 8 to 12 weeks of plan-check by using one of SDCI's pre-approved architectural plans. We help you pick the right one and build it.
Written by Aaron Elisha, founder of MNBE Construction & Development. WA license MNBECCD770R9. Updated 2026.
Seattle has done the architectural review for you.
Seattle's Department of Construction and Inspections runs a pre-approved DADU plan program. A small library of architectural designs that have already passed the city's full architectural plan-check. Homeowners who use one of these plans on a qualifying lot can skip that portion of the permit process and shave 8 to 12 weeks off the total timeline.
Lot-specific reviews still happen. Structural engineering for your specific soils, utility connections, setback verification, tree retention. The architectural review (which historically takes the longest) is what disappears. The program is Seattle-only. It does not extend to Bellevue, Kirkland, Redmond, or any other Eastside city.
Pre-approved is the right answer for most lots. Not all.
Three things you gain. Three things you give up. Read both sides before you commit.
Skip the architectural review
The biggest time savings: 8 to 12 weeks of plan-check disappears. Instead of waiting on Seattle DCI to review the architectural drawings line by line, the city already approved the design.
Predictable corrections cycle
Pre-approved plans have already cleared the corrections that catch new designs. Lot-specific corrections still happen but the volume is lower and the response cycle is faster.
Cost-effective on the right lot
If your lot fits a published plan as-drawn, the plan license cost is usually less than custom design fees. Plus the time savings reduces financing interest.
Limited customization
Major changes void the pre-approval. If you want a different roofline, different window placement, or a different footprint shape, custom design is the right path.
Lot fit constraints
Pre-approved plans have specific dimensions. A lot whose buildable envelope is shaped differently than the plan footprint may not work.
Plan license still costs money
Plans are not free. Architects who designed pre-approved plans license them for a fee. Add to project budget alongside design and permit costs.
When a pre-approved plan is the right answer for your lot.
You like one of the published designs as drawn. The pre-approved library has compact studios, one-bedroom layouts, and two-story two-bedroom configurations. If one of them matches your aesthetic and your space program, the time savings is essentially free.
Your lot's buildable envelope matches the plan footprint. Pre-approved plans have specific dimensions and orientation requirements. We verify lot fit during feasibility before recommending a plan.
Time matters more than design uniqueness. Renting the DADU sooner offsets the standardized look. Aging-in-place projects on a deadline benefit. Construction loan terms with carry costs benefit.
Conversely, custom design is the right answer when you want a specific architectural look, your lot has unusual shape or slope that no published plan addresses, or you want to integrate the DADU with the main house's existing aesthetic. We build both ways. The recommendation is yours after we lay out the math.
Pre-approved DADU build, four phases.
- Weeks 1 to 2
Feasibility + plan match
We walk your lot, run the zoning and HB 1337 analysis, and identify which pre-approved plans fit your buildable envelope. You pick the one you like best from the matches.
- Weeks 2 to 6
Plan license + lot-specific drawings
We license the chosen plan from the architect, prepare lot-specific drawings (foundation, utilities, site layout), and submit to SDCI.
- Weeks 6 to 14
Permit + corrections
SDCI reviews lot-specific items only, not the architectural design. Corrections cycle is shorter and more predictable than full plan-check.
- Weeks 14 to 32
Build + handover
Foundation through finish, supervised by Aaron personally. Standard MNBE 18-week build window applies. Certificate of occupancy at the end. One-year workmanship warranty included.
Decide Between Paths
Pre-approved is one path. Here are the others.
Service
Custom DADU
Custom-designed DADU. Your aesthetic, your layout, longer permit timeline.
See custom DADU →
Step One
Feasibility
Match your lot to a plan, or know that custom is the right answer instead.
See feasibility →
The Law
HB 1337 Explained
The state law that determines what your lot allows. Pre-approved plans pair with HB 1337 to compress permit timelines further.
Read the guide →Frequently Asked
Pre-approved DADU plan questions Seattle homeowners ask before they sign.
Six practical answers from a builder who has built from multiple pre-approved sets. If yours is not here, call us. Two minutes on the phone usually clears it up.
Still have questions?
We answer the phone Monday through Saturday. Two minutes on the call usually gets you further than an hour online.
Seattle's Department of Construction and Inspections published a small library of architectural plans that have already passed full plan-check. Homeowners who use one of these plans on a qualifying lot can skip the architectural review portion of the permit process, which typically removes 8 to 12 weeks from the total timeline. The plans are paid for by the homeowner (not free) but the time savings often justify the plan license. The program is Seattle-specific. It does not exist on the Eastside.
8 to 12 weeks on average. Standard Seattle DADU plan-check runs 3 to 6 months. Pre-approved DADU plans skip the architectural review portion of that, leaving only the structural and lot-specific reviews. Realistic compression: from 4 month average to 2 to 2.5 month average. The total project timeline drops from roughly 7 to 10 months down to 5 to 7 months when paired with MNBE's faster build pace.
Sometimes. Pre-approved plan licenses cost between roughly $4,000 and $10,000 depending on the design and the architect. A custom DADU design from MNBE's in-house team runs higher than that floor but you get exactly the layout you want. The real savings on pre-approved is the 8 to 12 weeks of compressed permit time. If financing is part of your project, the time savings translates directly into avoided interest costs that can offset or exceed the plan license fee.
Limited customization, yes. Cosmetic changes (paint colors, finish materials, fixtures) do not affect the pre-approval. Layout changes inside the existing footprint are sometimes acceptable but require a small architectural review. Any change to the building footprint, height, or window openings typically voids the pre-approval and pushes the project back into full plan-check. We help homeowners decide which customizations are worth the time cost during the consultation.
Depends on lot dimensions, setback envelope, height limit, your privacy goals, and finish preferences. Seattle's published plans range from compact studio configurations to two-bedroom two-story designs. We have built from multiple pre-approved sets and can advise which ones fit your specific lot, your budget, and the look you want. The selection happens after the feasibility step so you know the lot is buildable before you commit to a plan.
No. The pre-approved DADU program is a Seattle SDCI initiative only. Bellevue, Kirkland, Redmond, Mercer Island, Sammamish, Issaquah, and Newcastle all have their own permit processes and none of them have published a pre-approved plan library. Homeowners outside Seattle still get HB 1337's other benefits but not this specific time savings. We design custom for those projects.
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