"We hired MNBE to build our ADU in Bellevue, and the entire experience was amazing. They handled everything from foundations and framing to kitchen, siding, windows and HVAC."
Zena Heywood
Bellevue, WA · Attached ADU
FIVE-STAR RATEDRATED ON GOOGLE
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Can an ADU be two stories?
Yes, in Seattle, Bellevue, Kirkland and Redmond. State law sets a 24-foot floor for ADU height limits, and each city's own limit decides how much room two stories get. Answered by MNBE founder Aharon Ben Elisha. Checked October 28, 2026.
RCW 36.70A.681(1)(g) 24-foot state floor Two-story DADUs allowed
The Short Answer
Yes, with each city's height limit.
Yes. Under Washington's ADU law, a city can't set an ADU height limit under 24 feet, unless the house itself is limited to less. Seattle, Bellevue, Kirkland and Redmond all allow a two-story DADU, including a unit over a garage.
What shapes the design is each city's number. Seattle, Kirkland and Redmond let a DADU go as high as a house in the same zone. Bellevue caps a DADU at 24 feet, which fits two stories with a modest roof.
Height is only one limit. A two-story ADU also has to fit the city's size cap, floor area, setbacks and lot coverage, and parts of the building close to the property line can have lower limits. Kirkland, for example, keeps the part of a DADU inside the rear yard at or under 15 feet.
What we are building in Kirkland
Our two-story DADU in Kirkland is under construction now. Follow it stage by stage on the Kirkland DADU project page.
Seattle · Bellevue · Kirkland · Redmond
DADU height limits, city by city.
Each city's full rules, with the code section behind every number: Seattle, Bellevue, Kirkland and Redmond.
32feet
Seattle
Plus allowances for pitched roofs.
24feet
Bellevue
28 feet over an existing accessory building.
25–30feet
Kirkland
25 ft in RS zones, 30 ft in RSX and RSA.
38feet
Redmond
The Neighborhood Residential zone limit.
City by City
ADU height rules, city by city.
Detached ADU height limits in the main single-family zones. Each city measures height its own way.
| Where | Height limit for a detached ADU | Source |
|---|---|---|
| Washington State | Cities may not set an ADU roof height limit under 24 feet, unless the house's own limit is lower. | RCW 36.70A.681(1)(g) |
| Seattle | Same as the house: 32 feet in Neighborhood Residential zones, plus pitched-roof allowances, 42 feet in some cases. | SMC 23.44.070 |
| Bellevue | 24 feet to the highest point, or 28 feet as an addition over an existing accessory structure. | LUC 20.20.120 |
| Kirkland | Same as the house: 25 feet above average building elevation in RS zones, 30 feet in RSX and RSA. Parts inside the rear yard: 15 feet. | KZC 115.07 |
| Redmond | The zone's height limit, 38 feet in Neighborhood Residential. Other accessory buildings: 22 feet. | RZC 21.04.1120 |
| Unincorporated King County | An ADU may not exceed the base height of its zone. In the R-4 to R-8 zones that base height is 35 feet. | KCC 21A.08.030 |
Checked October 28, 2026. A plain-English summary, not legal advice. The code governs, and we confirm it for your lot.
Reviews
What Seattle homeowners say about building with MNBE.
Verified five star reviews from owners we guided through ADU feasibility, permitting, and construction.
"We hired MNBE for a full renovation of our 100 year old home and the results exceeded expectations, structural upgrades, new insulation, a luxury bathroom, a high end kitchen, a new roof and mini split AC."
Dave Gierok
Redmond, WA · DADU
"My mom hired MNBE Construction for her two-bedroom DADU in Seattle, and watching the process up close was impressive. They did it all: design, architectural plans, the building permit, and the full construction. … The communication was excellent and there were never any surprises."
Maryam Z.
White Center, WA · ADU
Schedule Free Estimate
FIVE-STAR RATEDRATED ON GOOGLE
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FAQs · Related questions
Two-story ADU questions.
More answers: How many ADUs can I build on my lot? · Can an ADU have its own address? · Do you have to live on the property?. City rules: Seattle, Bellevue, Kirkland and Redmond.
In Seattle, Bellevue, Kirkland and Redmond, yes, as long as the building fits the height, size and setback limits. Seattle doesn't count up to 250 sq ft of attached garage toward the ADU size cap, and Bellevue doesn't count up to 300 sq ft of parking or unheated storage.
Size caps count floor area on every level, so a two-story ADU spreads the same floor area over a smaller footprint. On tight lots, where lot coverage is the limit, that often helps.
Each city measures differently. Bellevue measures to the highest point, Kirkland from the average building elevation around the structure, and Redmond from the average finished grade. We check it against your lot's grade during design.
It depends on the lot. Redmond's Neighborhood Residential zone allows 38 feet. Seattle's limit is generally 32 feet plus pitched-roof allowances, and 42 feet when certain conditions are met, such as keeping a large tree. Kirkland allows 25 to 30 feet and Bellevue 24 feet.
Contact Us · Free Estimate
Tell us about your project.
We'll check your address against your city's ADU code and get back to you within one business day with a clear next step.
Contact information
Thank you for considering MNBE. Thank you for considering MNBE. Tell us your address and we will tell you, in writing, what your city's code allows on your lot. We respond within one business day, Monday through Saturday.
(206) 637 0044
info@mnbe-wa.com
2014 Fairview Ave Unit 2308, Seattle, WA 98121