What's included
What Our ADU Construction Service Includes
An accessory dwelling unit is a complete small home, with its own kitchen, bathroom and entrance.
- A feasibility check of your lot, zoning, utilities and access
- Design, plans and building permits for the unit
- Foundation, framing, roofing and a weathertight building shell
- Plumbing, electrical and heating for a full kitchen and bathroom
- Insulation, drywall, flooring, paint and fixtures through the final inspection
Local expertise
Building an ADU in Stanwood
Washington law now makes ADUs possible on far more lots than before.
Washington's 2023 ADU law, House Bill 1337, requires cities like Stanwood to allow up to two ADUs on residential lots that allow a single-family home within the urban growth area. The units can be attached, detached or a mix of both. Cities cannot require the owner to live on the property, except where the unit is used as a short-term rental. Properties outside the urban growth area follow Snohomish County's rural rules instead.
That opens real options for Stanwood households. About two thirds of the city's homes are single-family houses, based on U.S. Census data. Many families build an ADU so aging parents can live close by, give adult children a first home or add long-term rental income. Each lot still has limits, such as setbacks, utility capacity and access, so we check those first.
A detached ADU is a new building in a wet climate, and we build it with that in mind. Site drainage, a well-flashed shell and a dry crawl space or slab matter as much as the finishes. We repair water damage for a living, so we detail the building envelope to keep water out. Garage conversions get the same attention to slab moisture and insulation.
Our process
How ADU Construction Works
Five stages from the first site visit to handing over the keys.
Check feasibility and zoning
We look at your lot, the location options and the existing utilities. We confirm what the City of Stanwood or Snohomish County allows for your property. You learn early which ADU type fits and what it will involve.
Design, plans and permits
The unit is designed around how it will be used and what the lot allows. Plans and any engineering are prepared and submitted for permits. You get a written scope, estimate and schedule before construction starts.
Site work and foundation
Utility trenches are dug for water, sewer or septic, and power. Footings and a foundation go in, with drainage planned around the building. Inspections happen at each required stage.
Frame, dry in and rough in
Walls and roof are framed, sheathed and wrapped, and windows and roofing make the shell weathertight. Plumbing, wiring and heating are then run and inspected. Attached units and conversions get any required fire separation.
Finish and final inspection
Insulation, drywall, flooring, cabinets, fixtures and paint complete the unit. Final inspections close out the permit. We walk through the finished ADU with you before handing it over.
ADU types
ADUs We Build
The right ADU depends on your lot, your budget and who will live in it.
Detached backyard cottages
A detached ADU gives the most privacy for both households. It needs its own foundation and utility runs. It works best on lots with room in the back or side yard.
Attached ADUs
An attached unit is built onto the house, much like an addition, with its own entrance. It shares a wall and often utility connections with the main home. That can lower the cost compared with a detached unit.
Garage conversions
Turning a garage into a living unit reuses an existing structure. The slab, walls and ceiling need insulation, moisture control and egress windows. It can be the fastest route to an ADU.
Interior conversions
A bonus room, lower level or wing of the house can become a separate unit. It needs its own entrance, kitchen and bathroom. Existing space keeps construction costs down.
ADU FAQ
ADU Construction Questions, Answered
Common questions about building an ADU in Stanwood, WA.
Can I build an ADU on my property in Stanwood?
Most likely, if your lot allows a single-family home within the urban growth area. State law requires the city to allow up to two ADUs on those lots. Setbacks, utilities and access still apply, and we confirm them for your property.
Can I rent out an ADU?
Long-term rentals are generally allowed, and cities can no longer require the owner to live on site for most ADUs. Short-term rentals can have different rules. We recommend confirming your plans with the city before design.
How long does it take to build an ADU?
Design and permitting often take a few months. Construction usually takes several more, depending on the type and size. Garage and interior conversions tend to be faster than detached cottages.
Does an ADU need separate utilities?
It depends on the unit and the utility providers. Some ADUs share connections with the main house, while others need their own. We check water, sewer or septic, and power capacity during the feasibility stage.
What is the difference between an ADU and a home addition?
An ADU is a separate dwelling with its own kitchen, bathroom and entrance. A home addition adds rooms to the main house. If you just need more space for your own household, an addition may be simpler.
Are impact fees lower for an ADU?
Under state law, impact fees for an ADU cannot exceed half of what a new single-family home would pay. Other permit and utility connection fees still apply, and we include them in your estimate.
A second home on your lot, built right.
We take your ADU from the zoning check through construction and the final inspection, with one point of contact throughout. Flexible financing is offered through Enhancify, and 0% interest options may be available.
Weighing your options? See our home additions, flooring installation and residential construction pages too.