Transparent Pricing

How Much Does an ADU Cost?

Honest, transparent pricing for ADU projects in the Portland-Vancouver metro area. Every project is unique, but here are realistic ranges to help you plan.

Garage Conversion

$120,000 – $180,000

$240 – $360/sq ft · 3-5 months · ~400-500 sq ft

Most affordable option

Existing foundation & frame

Fastest build time

Minimal site prep

Full kitchen & bath

Attached ADU

$150,000 – $250,000

$275 – $450/sq ft · 4-6 months · ~400-600 sq ft

Close family living

Shared wall reduces cost

Shared utilities possible

Separate entrance

ADA options available

Detached ADU

$180,000 – $350,000+

$300 – $500/sq ft · 6-10 months · ~400-800 sq ft

Cottage Cluster

$400,000 – $800,000+

$250 – $400/sq ft · 10-16 months · 4-8 units

Maximum ROI

Multiple rental units

Shared amenities

HB 2001 compliant

Strongest returns

What Affects ADU Cost?

Beyond the base construction, several factors influence your total project budget.

Permits & SDCs

Building permits ($6k-$10k), SDCs ($36k+ in Portland – eligible for waiver), engineering fees.

Site & Foundation

Excavation, foundation ($10k-$15k), utility connections, and any demolition needed.

Finishes & Fixtures

Standard vs. premium finishes can swing costs by $20k-$50k. Cabinets, counters, flooring, fixtures.

Special Features

Solar panels, smart home tech, aging-in-place features, premium insulation, heated floors.

Portland SDC Waiver: Save Up to $36,000+

Portland homeowners can save tens of thousands through the System Development Charge (SDC) Waiver Program. By signing a 10-year covenant agreeing not to use the ADU as a short-term rental, you can have SDC fees waived entirely.

$36,000+

Potential Savings

10 Years

Covenant Period

No Short-Term Rentals

Requirement

Financing Options

Multiple financing paths are available for ADU construction:

Home Equity Loan (HELOC)

Leverage your existing home equity to fund ADU construction. Often the most straightforward option with competitive rates.

Construction Loan

Specialized loans designed for new construction projects. Funds disbursed in stages as building progresses.

Cash-Out Refinance

Refinance your mortgage at current rates and use the equity for your ADU project.

Get Your Personalized Estimate

Every project is unique. Tell us about yours for a detailed, no-obligation estimate.