Frequently Asked Questions

An Accessory Dwelling Unit (ADU) is a secondary housing unit on your property—either detached, attached, or converted from existing space like a garage. ADUs provide incredible ROI through rental income potential ($1,500-$3,000+ monthly), multigenerational living flexibility, and typically boost property values by 20-30%. They're perfect for aging-in-place solutions, guest accommodations, or creating passive income streams.

Yes! Thanks to Portland's Residential Infill Project, ADUs are now allowed in all residential zones throughout the city. Each base zone has specific allowances and design standards, but the opportunity exists citywide. We navigate these regulations daily and ensure your ADU meets all local requirements.

Detached ADUs can be up to 75% of your primary dwelling's living area or 800 square feet, whichever is less. Height is typically limited to 20 feet, with specific setback requirements from property lines. We'll assess your lot during our free site visit to determine the optimal size and placement for your ADU.

Most single-family zones require a minimum 5 ft rear and side setback for a detached ADU. The maximum height is 20 ft measured to the midpoint of the roof (or the height of the main house—whichever is lower). If you match the primary home’s roof pitch, you may go a bit higher, but the city caps overall wall length and window placement to protect neighbors’ privacy.

No. Portland & Vancouver removed the parking requirement for ADUs city-wide. As long as you don’t trigger other land-use reviews (e.g., environmental zones), you can build an ADU without adding a new driveway or parking pad. Street parking impacts are considered negligible for one additional dwelling on a residential lot.

ADU size limits vary by location and lot size, but typically range from 400 to 1,200 square feet. We'll help determine the maximum allowable size for your property during the consultation.

Turn-key ADU projects typically range from $180,000-$350,000, depending on size, finishes, and site conditions. This includes design ($15,000-25,000), permits ($8,000-15,000), site work ($20,000-40,000), construction ($120,000-250,000), and finishes. We provide fixed-price proposals so you know exactly what to expect.

Yes! We work with local credit unions and lenders who understand ADU projects and can factor future rental income into debt-to-income calculations. Popular options include HELOCs, cash-out refinancing, and construction loans. We'll connect you with trusted lending partners during your consultation.

Yes—property taxes will rise, but in Oregon and Washington the bump is usually small next to ADU rental income. Oregon’s “Changed Property Ratio” adds only part of the new value, while Washington taxes the ADU as new construction at the local levy rate. Expect a few hundred to a couple-thousand dollars extra per year, yet rents around $1.4k–$3k+ per month still leave most owners comfortably cash-flow positive.

Common extras include utility line upgrades (larger water or electrical service, $2k–$5k), sewer connection fees ($1k–$3k), and System Development Charges (SDCs). Portland currently waives SDCs for ADUs used as long-term housing, but you’ll pay them if you register as a full-time short-term rental. Soil remediation, tree removal, or steep-slope foundations can also add 5–10 % to your budget. We flag these in your feasibility report so nothing creeps up later.

Yes! While we offer pre-designed models, each can be customized to meet your specific needs and preferences while maintaining compliance with local regulations.

We use high-quality, durable materials that meet or exceed building codes. Our standard packages include premium finishes, and we offer various upgrade options.

Standard review takes 8-12 weeks from submittal to Ready-to-Issue. This includes plan review, life-safety evaluation, and coordination with various city departments. We handle all permit coordination, checksheet responses, and city communications to keep your project moving efficiently through the approval process.

Detached new-build ADUs typically take 2-4 months to complete. We build in weather contingencies and coordinate all trades to maintain efficient timelines. You'll receive regular progress updates and milestone communications throughout construction.

Yes! We're a complete design-build firm handling feasibility studies, architectural design, structural engineering, permit submittal, construction, and final inspections. You'll work with one dedicated team from concept to completion, ensuring seamless communication and accountability.

Code requires sequential inspections: (1) Footing/Foundation, (2) Underground Plumbing/Electrical, (3) Framing & Shear Walls, (4) Rough-in MEP, (5) Insulation & Air Barrier, and (6) Final Building + Life-Safety. Premier ADU Builders schedules every inspection, meets the inspector on-site, and sends you a same-day summary so you’re never chasing paperwork.Yes! We're a complete design-build firm handling feasibility studies, architectural design, structural engineering, permit submittal, construction, and final inspections. You'll work with one dedicated team from concept to completion, ensuring seamless communication and accountability.

We keep you in the loop with regular progress snapshots—photos, milestone checklists, and a look at what’s coming next—and invite you on site whenever the build reaches key stages. We’re always happy to hop on a call if you’d like more detail. As a full-service design-build firm, we take care of everything from feasibility and plans to permits, construction, and final sign-offs, so you work with one dedicated team from start to finish.