ADU Construction in Burien
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Last updated June 2026
Burien ADU Construction — Build a Rental Unit Under HB 1337
Proximity to Sea-Tac Airport and the A Line BRT corridor running through 98168 makes Burien one of the more reliable rental markets in south King County. Under WA HB 1337 (2024), most single-family lots here can now carry up to two ADUs — a detached backyard unit, an attached addition, or a basement conversion — without the restrictive lot-coverage fights that used to kill these projects before the law changed. The 1950s and 1960s ranchers filling Gregory Heights and Seahurst were built on 6,000–8,000 sq ft lots with modest footprints, which leaves genuine backyard room for a 640–800 sq ft DADU if the setbacks work out. Vladislav Volkov at TopVolk Construction has handled ADU permits and builds across King County since 2017 — 100+ projects completed, direct communication from day one, no sales staff relaying messages. City of Burien Community Development reviews the permit application, and getting that process right upfront saves weeks. Call (206) 591-1096 to set up a free on-site consultation.
Burien's 98148 zip covers the western residential blocks closer to Three Tree Point and Seahurst Park, while 98166 runs through south Burien toward the Highline area. Most housing stock dates to 1955–1975 — post-and-pier foundations in the older blocks, slab-on-grade for the 1970s builds closer to I-5. That distinction matters for ADU design: a post-and-pier house in 98148 may have usable crawlspace depth that could be converted with a floor system upgrade, proper vapor barrier installation, and DriCore subfloor panels to handle the moisture that accumulates October through April. Detached ADUs in the 98166 zip need to hit City of Burien setback requirements — typically 5 feet rear and side — and stay under the 24-foot DADU height limit. Lot coverage here maxes at 40–45% depending on zoning designation, so a real site analysis before design saves surprises later. The A Line transit corridor along SR-99 also qualifies most nearby lots for parking minimum exemptions under HB 1337, which removes one of the common barriers to DADU approval on tighter lots.
Common ADU Construction Concerns in Burien
DADU, Attached ADU, or Basement Conversion — Picking the Right Type for Your Lot
The three ADU types under HB 1337 aren't interchangeable — each has different cost, rental potential, and structural complexity. A DADU (detached accessory dwelling unit) gives tenants private outdoor space and the owner maximum separation, but requires its own foundation, roof system, and full MEP rough-in. An attached ADU built alongside the main house or over a garage runs $30,000– $60,000 less because foundation and roof framing are already in place. Basement conversions in Burien's older ranchers often need LVL beam work to achieve the 7-foot minimum ceiling height under IRC — common in the split-levels near Gregory Heights where partial basements sit at 6'8". The right answer depends on how much lot coverage remains, the existing grade, and where utility connections land. Vladislav walks every site before quoting because no floor plan renders those variables from a desk.
Utility Separation — Shared Connection vs. Independent Meter for a DADU
Shared water and sewer connections are cheaper upfront — one meter, one lateral — but they create complications when renting to an unrelated tenant, and they put the entire supply line at risk if the main dwelling's plumbing has issues. Separate utility connections for a DADU in 98166 typically run $8,000–$15,000 for a new sewer tap and water service, depending on distance from the main and whether a Navien or Rinnai tankless water heater is being sized for the unit. City of Burien requires both connections to be shown on permitted drawings. Shared connections need proper sizing review — an existing 3/4-inch supply line that's already marginal will cause chronic pressure problems once a second kitchen and bath are running simultaneously. The plumbing permit gets coordinated alongside the building permit so nothing gets discovered mid-inspection.
Navigating the City of Burien Permit Process for ADU Construction
Burien runs its own building department through City of Burien Community Development — separate from King County DPER, which handles unincorporated county areas. An ADU permit here requires a complete drawing package: site plan showing setbacks and lot coverage, architectural floor plans and elevations, structural drawings (including LVL beam specs if any load path gets modified), and a Washington State Energy Code compliance worksheet. Plan review typically runs 6–10 weeks for a new DADU. Burien does not offer a pre-approved ADU plan program like Seattle's MAP process, so each project goes through standard review. TopVolk prepares the full permit application in-house and submits directly — WA Licensed Contractor, all permits pulled under the contractor's name. Expect 8–12 weeks from signed contract to permit approval, then 3–5 months of construction to final inspection.
What ADU Construction Actually Costs in Burien — and What Drives the Number
A detached ADU in Burien runs roughly $180,000–$280,000 for a 600–800 sq ft unit, fully permitted and finished. Attached ADUs and garage conversions start lower — $90,000–$160,000 — because foundation and roof framing are already there. What pushes cost up: sloped lots requiring concrete grade beam work or retaining walls, separate utility connections, and finish-level choices like quartz countertops, large-format porcelain tile in the bath, or Milgard vinyl windows upgraded to fiberglass for noise attenuation near SR-99. TopVolk quotes line-item — actual material specs and sub-trade costs, not a range that quietly balloons after demo begins. The deadline penalty for missed project milestones is written into the contract. With 1-bedroom rents in 98168 running $1,400–$1,800 per month, most owners recover a DADU investment within 10–12 years while the unit also adds assessed value immediately.
Structural and Moisture Surprises in Burien's Older Homes During ADU Conversions
The 1960s and early 1970s housing stock in 98148 and 98166 carries predictable surprises. Crawlspaces under post-and-pier foundations collect moisture from October through April — inadequate vapor barrier, missing rim joist blocking, and R-19 batt insulation falling out of the floor cavity are standard findings. Before designing an attached ADU or basement conversion, a proper crawlspace inspection often uncovers sister joist repairs, pressure-treated (PT) lumber replacement at ground-contact points, and subfloor replacement. Aluminum wiring common in Burien homes built between 1965 and 1973 has to be addressed before adding a second dwelling unit with its own panel. These aren't items TopVolk hides in a change order — they're things Vladislav looks for during the initial site walk so the quote reflects actual scope. Building on a lot with an older main house is straightforward; doing it without a realistic pre-construction assessment is how $200K projects turn into $260K projects.
Frequently Asked Questions
How fast can TopVolk get to Burien for an ADU consultation?▼
Burien sits about 20 minutes south of Seattle via I-5 or SR-99, and TopVolk works regularly throughout King County — scheduling a site visit in 98168 or 98148 is typically possible within a week of first contact. Vladislav comes to the property personally, not a sales rep. The on-site consultation covers lot coverage calculation, setback review, a look at existing utility connections, and a realistic budget range before any design work starts. Call (206) 591-1096 to get on the schedule. Most full ADU projects run 4–7 months from signed contract to final inspection, with permit plan review being the longest variable — typically 6–10 weeks at City of Burien.
What does a DADU cost to build in Burien?▼
A detached ADU in Burien runs roughly $180,000–$280,000 for a 600–800 sq ft fully permitted unit. Attached ADU or garage conversion work starts around $90,000–$160,000. What moves the number most: lot slope (a 15% grade adds foundation cost), utility separation (shared vs. independent meter), and finish specification — Milgard vinyl windows are standard; upgrading to Pella fiberglass makes sense on lots near SR-99 for sound attenuation. TopVolk provides a line-item quote after the site visit — actual specs, not a range that shifts post-demo. Call (206) 591-1096 to schedule a free on-site estimate with real numbers.
Does Burien require permits for ADU construction, and how does the process work?▼
Yes — Burien is an incorporated city, so permits go through City of Burien Community Development, not King County DPER. A new DADU requires a full drawing package: site plan, architectural plans, structural drawings, and a Washington State Energy Code compliance worksheet. Plan review runs 6–10 weeks. Burien does not offer pre-approved ADU plans like Seattle's MAP program, so standard review applies to every project. TopVolk prepares and submits the permit package directly — WA Licensed Contractor, all permits pulled in the contractor's name. Permit fees for a new DADU typically run $3,000–$6,000 depending on valuation. Timeline: contract to permit approval averages 8–12 weeks; framing and MEP rough-in begin once the permit is issued.
Can you build a DADU on a sloped backyard lot in Burien?▼
Sloped lots are common in the hillside neighborhoods near Three Tree Point in 98148, and they add foundation complexity without ruling out a DADU. Options include a concrete perimeter foundation stepped to follow grade, a post-and-beam system on concrete piers, or slab-on-grade with fill and retaining walls. A stepped perimeter foundation on a 15% slope typically adds $15,000–$25,000 to the foundation line versus a flat lot. Structural drawings for sloped foundations require a licensed engineer's stamp — TopVolk coordinates that as part of the permit package, not as a surprise line item. Vladislav reviews grade during the initial site walk and shows each option with actual cost breakdowns.
What warranty comes with a TopVolk ADU build?▼
Washington State's implied warranty of habitability covers structural integrity for the life of the building; workmanship is covered for one year post- completion. Materials carry manufacturer warranties — Milgard windows run a limited lifetime warranty, Trex or TimberTech decking (if included) carries a 25-year fade and stain warranty, and roofing warranties are tied to the specific product specified. Beyond warranties, the contract includes written deadline penalties: missed project milestones cost TopVolk, not the homeowner. All inspections — rough-in, framing, MEP, and final — are completed with the AHJ before any work gets covered. Call (206) 591-1096 to review a sample contract before committing to anything.
Do you cover other cities near Burien for ADU construction?▼
TopVolk covers King County, Snohomish County, Pierce County, and Kitsap County. Des Moines, Tukwila, SeaTac, Renton, and Federal Way are all within regular service range — most project starts in south King County get scheduled within 2–4 weeks of permit approval. Permit jurisdictions vary city to city: Renton and Des Moines each have their own building departments, unincorporated King County uses DPER, and Burien uses its own Community Development department. Vladislav knows which AHJ applies before the permit package gets assembled, so there's no confusion mid-project about who's reviewing what. Call (206) 591-1096 or reach out through topvolkconstruction.com to get a consultation scheduled.
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ADU Construction Services in Burien
ADU design
Permit processing
Foundation work
Complete construction
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What Our Burien Customers Say
Vlad and his team did an amazing job! They built our deck in just 3 days—no issues at all. Communication was easy, and Vlad helped us choose right deck planks. Installation was quick and flawless. Highly recommend!
Really happy with the service! Vlad was easy to communicate with and helped us to find the best garage door opener. The installation was quick and he did a perfect job. A few months later, I had a question and he came by the same day - even on a weekend. That kind of follow-up is rare these days!
Vlad replaced a bathroom exhaust fan and gave me a reasonable quote up front with no hidden fees. While replacing the fan, he discovered a plumbing vent issue causing mold. He fixed the pipe and treated the mold at a reasonable cost. I really appreciate his honesty!
Outstanding work done by Vlad and team for our home cabinet/living room interior work. Very professional and reasonable charges. Love the service.
We hired TopVolk for a full kitchen remodel and couldn't be happier. From the initial consultation to final walkthrough, Vlad was professional and attentive to every detail. The result exceeded our expectations!
Excellent bathroom renovation! Vlad completed the project on time and on budget. His attention to detail and craftsmanship is outstanding. We'll definitely hire him again for future projects.