An ADU builder in Beaverton is a licensed contractor who designs and constructs accessory dwelling units — detached backyard units, garage conversions, attached additions, and junior ADUs (JADUs). Because an ADU is a complete second dwelling, the builder coordinates foundation, framing, plumbing, electrical, and HVAC work and pulls it through Beaverton's permit process and utility connections. Not every general contractor has built one, so the right builder is one with ADU-specific experience in Oregon.
What ADU Builders Cost in Beaverton [4][5]
Based on our Beaverton cost data, expect the following ranges from local ADU builders. Quotes for the same scope typically vary 20-40% between contractors, so getting at least three bids is the single best way to control cost.
| New Detached ADU (all-in) | $150,000-$320,000 |
| Cost per Sq Ft | $150-$300 |
| Garage Conversion | $100,000-$180,000 |
| Prefab / Modular ADU (installed) | $100,000-$240,000 |
| City Permit & Plan Review | Type 1 application fee plus valuation-based building permit fees (third-party guides estimate $2,500-$9,000) — Confirm with Beaverton Building Division |
| Impact Fees | System Development Charges (city, Washington County TDT, Clean Water Services) apply and can add five figures — Confirm current SDC schedule with Beaverton Site Development |
For a full line-item breakdown, see our Beaverton ADU cost guide. To confirm what you're allowed to build before you hire, review the Beaverton ADU rules (max detached size: 800 sq ft or 50% of the primary dwelling's gross floor area, whichever is less; owner-occupancy: Not required — Oregon law prohibits owner-occupancy conditions on ADUs).
Get Free ADU Quotes in Beaverton
Tell us about your project and we'll connect you with ADU builders serving Beaverton. Free, no obligation — you choose who to work with.
Takes about a minute.
Up to 3 independent local ADU builders — never more, and we tell them nothing you don't submit here.
Compare quotes, verify license & insurance, hire (or don't). No spam either way.
🔒 Your info is secure. We share it only with contractors quoting your project. No spam, no obligation.
How to Vet an ADU Builder in Beaverton
- License: Confirm a current contractor's license in Oregon and that it's in good standing. Ask for the license number and verify it with the state board.
- ADU-specific experience: Ask how many ADUs they've completed in or near Beaverton and request addresses or photos. ADU permitting and setbacks differ from a kitchen remodel.
- Portfolio & references: Get references from recent ADU clients and, if possible, visit a finished unit.
- Insurance: Verify general liability and workers' compensation coverage. Ask for a certificate of insurance.
- Written, detailed bid: Insist on an itemized, fixed-price or clearly-scoped bid — not a verbal estimate. It should state whether permits (Type 1 application fee plus valuation-based building permit fees (third-party guides estimate $2,500-$9,000) — Confirm with Beaverton Building Division), plan check (Included in building permit review — Confirm with Beaverton Building Division), and impact fees (System Development Charges (city, Washington County TDT, Clean Water Services) apply and can add five figures — Confirm current SDC schedule with Beaverton Site Development) are included.
- Permit handling: Confirm they manage Beaverton's permit process ("Type 1 land use application (Development Code 40.05.15, Director decision, ministerial) plus building permit", typically Commonly 2-4 months total from application to permit issuance — Confirm with Beaverton Planning Division) and who is responsible if revisions are required.
- Payment schedule: Avoid large upfront payments. A reasonable schedule ties payments to completed milestones.
Questions to Ask Before You Hire
- How many ADUs have you built in Beaverton in the last two years?
- Is your bid fixed-price, and what would trigger a change order?
- Are permits, plan check, and utility connection fees included?
- What's a realistic timeline, including permit review (Commonly 2-4 months total from application to permit issuance — Confirm with Beaverton Planning Division) and construction?
- Who is my point of contact and how are delays communicated?
- What warranty do you provide on workmanship?
- Can you share three recent Oregon ADU client references?
Finance Your ADU Project
Most ADU projects are funded through HELOCs, construction loans, or cash-out refinancing. Compare rates from top lenders.
Some links on this page are affiliate links. We may earn a commission at no extra cost to you. Learn more
Are you an ADU builder? Get Beaverton leads
Homeowners on this page submit real ADU project requests in Beaverton. We match each one to a local builder. Your first lead is free, then a small per-lead fee — no subscription, and you contract directly with the homeowner.
Get Beaverton ADU Leads →Frequently Asked Questions
How much do ADU builders charge in Beaverton?
How do I find a good ADU builder in Beaverton?
Do ADU builders in Beaverton handle permits?
How long does it take to build an ADU in Beaverton?
Get Free ADU Builder Quotes in Beaverton
Compare bids from experienced local Beaverton ADU builders. Free, no obligation.
Get Free Quotes →