ADU Construction in Vancouver, WA
I See Construct builds permitted accessory dwelling units (ADUs) for homeowners across Vancouver, WA, Battle Ground, and Clark County. ADU costs in Clark County and the City of Vancouver typically range from $120,000 to $350,000 depending on size, ADU type, and finish level. We coordinate the design, permits, and construction from start to final inspection so you have one point of contact throughout the entire project.
At a Glance
$120,000 to $350,000 depending on ADU type, size, site conditions, and finishes
6 to 14 months from contract to final inspection, including permit review
ADU Types We Build in Vancouver and Clark County
Detached ADUs (Backyard Cottages)
A detached ADU is a standalone structure built in the backyard of an existing single-family home. These are the most common type of ADU in Clark County and Vancouver, WA. Detached ADUs require their own foundation, framing, roofing, and utility connections. They are typically sized between 400 and 1,000 sq ft and can include a full kitchen, bathroom, and one to two bedrooms.
Attached ADUs (In-Law Suites)
An attached ADU shares at least one wall with the main home. This is a cost-effective option when the existing home has a suitable layout for creating a separate entrance and self-contained living space. Attached ADUs are common in neighborhoods like Orchards, Hazel Dell, and East Vancouver where lot size limits detached options.
Garage Conversions and ADUs Above Garages
Garage conversion ADUs repurpose an existing attached or detached garage into a habitable living space. ADUs above garages require the garage to be rebuilt or reinforced to support a second floor. Both options are popular in Battle Ground and Ridgefield where existing garages are already on the property.
The ADU Permit Process in Clark County
ADUs in unincorporated Clark County are permitted through the Clark County Department of Community Development. Properties within city limits, such as Vancouver or Battle Ground, use their respective city permitting departments. Washington state updated its ADU laws in 2021 to remove owner-occupancy requirements for most properties, making ADU rentals significantly more accessible.
The permit application for a detached ADU in Clark County requires site plans, floor plans, foundation details, and utility plans. Plan review currently takes 4 to 12 weeks depending on department workload. Construction begins after permit issuance and proceeds through rough framing, mechanical, electrical, and plumbing inspections before final approval.
What Affects ADU Cost in Vancouver, WA
ADU type:
Detached units cost more than attached or garage conversion ADUs due to foundation and roofing scope
Size:
Most ADUs in Clark County range from 400 to 900 sq ft; larger units cost more per total project
Site conditions:
Sloped lots, poor soil bearing capacity, or limited utility access add cost
Finish level:
Budget finishes versus custom cabinetry, tile, and fixtures can shift cost by $30,000 or more
Utility connections:
New sewer laterals, water meters, and electrical panels are separate line items
ADU Construction Timeline
A realistic ADU project timeline in Clark County breaks down as follows: design and permit preparation takes 4 to 8 weeks, county or city plan review takes 4 to 12 weeks, construction runs 3 to 6 months depending on ADU size and complexity, and inspections and final approval add 2 to 4 weeks at the end. Total project time from contract to move-in typically falls between 6 and 14 months.
We set realistic schedules from day one. Permit timelines in Clark County are outside our control, but we prepare applications correctly the first time to minimize back-and-forth with plan reviewers.
Neighborhoods and Areas We Serve for ADU Projects
I See Construct has built and managed ADU projects in Vancouver neighborhoods including Hazel Dell, Salmon Creek, Felida, Orchards, and East Vancouver. We also serve Battle Ground, Ridgefield, Woodland, and unincorporated Clark County. Our service area extends into Oregon, including Multnomah County and Clackamas County, for homeowners near the Columbia River who want ADU construction on the Oregon side.
Frequently Asked Questions
ADU construction in Vancouver, WA and Clark County typically ranges from $120,000 to $350,000. Detached ADUs with new foundations and full utility connections are at the higher end. Garage conversions tend to come in at the lower end of the range. Final cost depends on size, site conditions, and finish selections.
From contract signing to final inspection, ADU projects in Clark County typically run 6 to 14 months. This includes the permit application, plan review period (4 to 12 weeks at Clark County), construction, and final inspections. We will give you a project-specific schedule during the estimate process.
Yes. ADUs require a building permit in both the City of Vancouver and unincorporated Clark County. Unpermitted ADUs create serious problems for insurance, financing, and future property sales. I See Construct manages the entire permit application process for every ADU we build.
Yes. Washington state removed owner-occupancy requirements for ADUs for most properties in 2021, meaning you do not need to live in the main home to rent out the ADU. Local zoning and HOA rules may still apply, so we recommend verifying with Clark County or the City of Vancouver during the planning phase.
DADU stands for detached accessory dwelling unit, which is a standalone structure separate from the main home. ADU is the broader category that includes attached units, garage conversions, and basement apartments. Clark County uses ADU as the general term in its code. We build all three types.
Not every lot qualifies. ADU eligibility depends on zoning designation, lot size, existing setbacks, and utility access. Most single-family residential zones in Vancouver and Clark County allow at least one ADU. We review your property details during the free estimate to confirm feasibility before you commit.
Ready to Build Your ADU?
We work with Vancouver, WA homeowners from first conversation through final walkthrough. Get a straight answer on what it costs and how long it takes.