_edited_edited.png)
An accessory dwelling unit (ADU) refers to a distinct residential area located either within a dwelling or on the same premises as an existing residence. It's essential to note that these units can only be considered legal if they have undergone the proper permit approval. When a residential unit within a home is legally permitted, it is termed an attached accessory dwelling unit (AADU). In contrast, a legally approved unit situated on the property but separate from the main dwelling is referred to as a detached accessory dwelling unit (DADU) or a backyard cottage. It's worth mentioning that tiny houses with foundations fall into the category of DADUs.
AADU requirements:
An AADU is limited to 1,000 square feet in a neighborhood residential zone, including RSL, and up to 650 square feet in a low-rise zone
The AADU must meet current standards of the Seattle residential, building, mechanical, electrical, energy, land use, environmentally critical areas, and shorelines codes https://www.seattle.gov/DPD/Publications/CAM/cam116a.pdf
DADU requirements:
The minimum lot size required for a DADU is 3,200 square feet in neighborhood residential zones
A DADU is limited to 1,000 square feet of gross floor area in neighborhood residential zones, including RSL, and 650 square feet in a lowrise zone
The DADU must meet all the Seattle residential, building, mechanical, electrical, and energy code requirements that apply to single-family dwellings https://www.seattle.gov/DPD/Publications/CAM/cam116b.pdf
What Permits Do You Need?
If you're adding within an existing house, then you need https://www.seattle.gov/sdci/permits/permits-we-issue-(a-z)/construction-permit---addition-or-alteration
If you're building a detached unit, you need https://www.seattle.gov/sdci/permits/permits-we-issue-(a-z)/construction-permit---addition-or-alteration
If you're legalizing an existing unit, you need https://www.seattle.gov/sdci/permits/permits-we-issue-(a-z)/construction-permit---establishing-use
At Ark Design we help homeowners and real estate professionals with designing ADU/DADU for jurisdictions like Seattle, Bellevue, Kirkland, Kenmore, Redmond, and many others in King and Snohomish counties.
Whether you need tiny home plans, one story house plans, farm house plans, modern house plans, tiny house plans, barndominium house plans or any style house layouts, we’ll work with you every step of the way to create drawings that meet your specific needs and requirements.
Comments