ADU and DADU Builders in Redmond, WA
Redmond allows two ADUs or tiny homes on each residential lot, with an ADU capped at 1,000 square feet.
- We check creek buffers and aquifer zones for your lot before design.
- We request your permit through Plan Review Online and track every review.
- You approve a written, itemized price before work starts.
By appointment. Limited start dates.
- Over 200 projects
- 4.9 on Google
- 20+ years of experience
- WA license VOLCABI792C6
Four ways to add a unit in Redmond
RZC 21.04.1110 lets an ADU be added to the house, built inside it or placed in a detached structure. Each of these counts as one of the two units a lot may hold.
Attached ADU
An addition with its own entrance, kitchen and bathroom, kept within 1,000 square feet and the lot coverage limits.
ADU inside the house
A lower floor or wing turned into a separate unit. When it fills an entire floor, the code lets the city approve one larger than 1,000 square feet.
Detached ADU (DADU)
A backyard cottage that meets the same lot coverage limits as a house and is fitted with fire sprinklers, as Redmond requires for every detached ADU.
Garage conversion
A detached garage converted to an ADU is a detached unit, so it gets sprinklers, and one on an alley may stay on that lot line.
How an ADU differs from a DADU is on ADU Builders Across the Greater Seattle Area. Garage space that stays part of the house is on Garage Conversion, and the main house on home remodeling in Redmond.
Redmond ADU rules under RZC 21.04.1110
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The Redmond rule
Two ADUs or tiny homes
Each residential lot in Redmond can hold two ADUs or tiny homes. An ADU is capped at 1,000 square feet in total and a tiny home at 400.
What we doWe work out which mix fits your lot and how much floor area each unit can take.
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The Redmond rule
Sprinklers in every detached unit
Redmond requires fire sprinklers in new homes and in detached ADUs, so a backyard cottage or a converted detached garage is sprinklered.
What we doYour written, itemized price shows the sprinkler work as its own line.
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The Redmond rule
Lot coverage and the alley line
A detached ADU must meet the same lot coverage limits as a house, though it may sit right on a lot line that abuts an alley or right of way.
What we doOn an alley lot we place the unit on that line where it frees up the yard.
Redmond also maps critical areas under RZC 21.64, including aquifer recharge zones set by a lot's distance from the city's own water wells.
Redmond ADU permits and timeline
Redmond's Development Services Center issues permits through two online portals.
- Starting: an ADU that needs review begins as a request in Plan Review Online, and the city emails a permit number and upload instructions within 48 hours.
- Plans: submitted as PDFs; the city does not take paper plans.
- Trades: electrical, mechanical and plumbing work are separate applications from the building permit.
- During review: a Project Coordinator handles the file, and any missing detail comes back on an Additional Information Issues Matrix.
- Timeline: Redmond posts no review times for residential work, so we set your start date once the city responds. An issued permit expires if no inspection happens within 365 days.
How we build your Redmond ADU
One licensed team handles the lot check, the city and the build.
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Lot check and written price
We pull the critical area and aquifer layers, check sewer and power, and send a written, itemized estimate.
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Design and Plan Review Online
We draw the unit and its sprinkler layout, request the permit through PRO and answer the issues matrix.
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Build and warranty
One project manager runs the trades and inspections, and the unit carries our 2-year workmanship warranty.
Who you are hiring
A licensed general contractor, WA license VOLCABI792C6, a short drive from Redmond.
Over 200 projects
Finished across the company, kitchens and bathrooms to whole homes.
20+ years
How long our founder, Bar, has been building.
132+ cities
Across the 8 Western Washington counties we serve.
4.9 on Google
From our main Google Business Profile.
Look through Our Completed Remodeling Projects and our Remodeling Warranty for the Greater Seattle Area.
Finished bathrooms in Redmond
An ADU is built around a kitchen and a bathroom. These Redmond bathroom remodels show the finish our crews bring to every unit's bathroom.
What homeowners say about working with us
Had a great experience working with Volcano Builders on remodeling bathroom and flooring in my condo! Bar and his team were very professional from estimates to timely completion of the job! Highly recommend!
Volcano builders did a phenomenal job on my bathroom remodel. They exceeded my expectations on many levels. Their designer helped me pick out all the tile and bathroom accessories to make sure everything matched in style. Communication was great and response time very fast whenever I had questions for them. They estimated the project would take 5-6 weeks but finished in 4 weeks! Excellent job! Loooooove my new bathroom! Including pics of the Before… and the After!
I had an amazing experience with Volcano Builders! Bar was incredibly kind, communicative, and made the whole process smooth. We completely redid the bathroom,new flooring, vanity, tub, and wall tiles, and it turned out fantastic. I'm so happy with their work that I'm already planning my second bathroom and hopefully the kitchen too. Highly recommend them to anyone looking for quality work and great service!
Read more of our Google reviews, word for word, with video reviews from finished homes.
Our workmanship warranty
- 2 years standard. Our installation and labor are covered for 2 years from substantial completion.
- Up to 5 years. You can extend the workmanship coverage up to 5 years for an added charge, set in your contract.
- Not transferable. Coverage stays with the homeowner who signed the contract and does not pass to a new owner.
- Materials. Materials, finish materials included, carry the manufacturer's or supplier's warranty, and we help you file a claim.
Remodeling Warranty for the Greater Seattle Area
Related: Kitchen Remodeling Portfolio Across the Greater Seattle Area, Bathroom Remodeling Portfolio Across the Greater Seattle Area, ADU Builders Across the Greater Seattle Area, Home Remodeling Contractors in Redmond, WA.
Redmond ADU questions
How big can an ADU be in Redmond?
Up to 1,000 square feet under RZC 21.04.1110, and a tiny home up to 400. The city can approve a larger ADU when it fills an entire floor of the house.
Does a detached ADU in Redmond need sprinklers?
Yes. Redmond requires fire sprinklers in detached ADUs, as it does in new homes, and that includes a detached garage converted into a unit.
Can a backyard cottage sit on the lot line in Redmond?
Only on a lot line that abuts an alley or right of way. Elsewhere a detached ADU follows the usual rules and must meet the same lot coverage limits as a house.
How long does a Redmond ADU permit take?
The city emails a permit number and upload instructions within 48 hours of a Plan Review Online request, but it posts no review times for residential work. We set your start date once reviewers respond.
How do I get a price for a Redmond ADU?
Book a consultation below. We visit the lot, talk through the unit and send a written, itemized price before any work starts. For background, read How Much Does It Cost to Build an ADU? and our Remodeling Pricing Guide.
Book your Redmond ADU consultation
Four quick steps. Tell us about your project and we’ll reach out to discuss it and see if we’re the right fit.