★★★★★
Had a great experience with JDI Construction.
Definitely a reputable team. Highly recommend them. They definitely know what they are doing. Also very knowledgeable. Thank you.
Portland ADU Builder
JDI Construction, your trusted Portland ADU Builder, brings expertise in creating functional and elegant ADUs. Enhance your property value and living space with our quality services.
- Family-owned since 2007
- 5-year written warranty
- Licensed in WA & OR
Family-Owned Since 2007
500+ completed projects
Before & After
See how we transform real homes.
Drag the dividers to compare each project before and after we remodeled it. Every project below was designed, built, and finished by our JDI team.
Complete Home Remodel
Vancouver, WA 98685
See the full project 
Elegant Kitchen Remodel
Vancouver, WA 98665
See the full project 
Warm Wood Kitchen Remodel
See more kitchen projects
By the numbers
Portland & Vancouver's trusted design-build team since 2007.
Family-owned, with in-house crews, detailed written proposals, and one accountable team from first conversation to final walkthrough.
500+
Completed projects
4.9/5
Across 223+ Google reviews
18yrs
Family-owned since 2007
5yr
Written workmanship warranty
ADU Builder in Portland & Vancouver
An ADU (accessory dwelling unit) is a second, independent home on your lot — its own kitchen, its own bathroom, its own front door. Portland is among the most ADU-friendly cities in the country, but zoning and utilities are where these projects live or die.
A well-planned ADU adds usable square footage, real flexibility, and lasting value to a property you already own. A poorly planned one runs headlong into a setback line, an undersized electrical service, or a sewer connection nobody priced. The design is the fun part. The feasibility is the part that decides whether the project is worth doing at all — and it has to come first.
JDI is a design-build remodeler, which means the people drawing your ADU are the same people who will confirm what your lot allows, pull the permits, and swing the hammers. There is no handoff between an architect who never sees the site and a builder who inherits a design that doesn't fit. We keep design, permitting, and construction under one roof so the plan you approve is the plan that gets built.
Types of ADUs we build
Most homeowners assume "ADU" means a backyard cottage. It's one of four common paths, and the right one depends on your lot, your budget, and what you're trying to accomplish.
Detached (DADU / backyard cottage)
A freestanding standalone unit in the backyard. The most private and the most flexible in layout, and usually the strongest for rental income or long-term multigenerational use.
Attached addition ADU
A new self-contained unit built onto the existing house, with its own entrance. Shares a wall but not a living space — a good fit when the backyard is tight or you want the unit close.
Garage conversion
Turns an existing garage into a livable unit. Reuses a footprint and often a foundation, but trades a parking space and can carry surprises once walls open up.
Basement / interior conversion
Carves a separate unit out of existing interior space — typically a basement with its own entrance. Leaves the yard untouched, but egress, ceiling height, and moisture control drive the design.
The rules are the project
With an ADU, the code isn't a formality you clear at the end — it shapes the whole design from the first sketch. The rules differ meaningfully between Portland, Oregon and Clark County / Vancouver, Washington, and they get revised over time, so the only number that matters is the one that applies to your specific lot on the day you build. Here's the shape of what governs the design:
- Size caps. Jurisdictions limit how large an ADU can be, often tied to the size of the main house or the lot. This sets your maximum footprint before anything else.
- Setbacks. Minimum distances the unit must keep from property lines and other structures. On smaller lots, setbacks — not budget — often decide where and how big the ADU can be.
- Height limits. Caps on overall height, which influence whether you can build a second story or need to stay single-level.
- Parking. Whether an added off-street space is required varies by location and by proximity to transit, and it can quietly consume yard you were counting on.
- Owner-occupancy considerations. Some jurisdictions have applied requirements about whether the owner must live on the property. These rules change, so they need to be confirmed before you plan around renting.
- System development charges & permit fees. Connecting a new dwelling triggers utility and infrastructure charges plus permit costs. Categories to plan for, with amounts that depend on your jurisdiction and lot.
We confirm exactly what your specific lot allows before design. Before we draw a floor plan, we research the zoning, overlays, easements, and utility conditions tied to your parcel — Portland OR and Clark County / Vancouver WA rules are not the same — and confirm what's actually buildable. That way the design you fall in love with is one you can permit and finish, not one that dies at the counter.
Utilities and the site work nobody budgets for
An ADU is a full second home, and a second home needs its own connections to water, sewer, and power. This is the part of the project that lives underground and behind walls, and it's where budgets slip when someone prices the building but not the site. Here's what we scope up front:
1
Sewer & water lateral taps. A new unit typically needs connections to the sewer and water mains. Depending on where the lines run, that can mean trenching across the lot and paying connection charges.
2
Electrical panel & service capacity. Your existing panel may not have room for a second dwelling. Adding an ADU can require a panel upgrade or a service increase from the utility.
3
Separate metering. If you plan to rent, separate meters for power, water, or gas keep the ADU's utilities off your own bill — decisions best made before the walls close.
4
Stormwater management. New roof and paved area sheds water that has to go somewhere. Jurisdictions require it managed on site, which can mean drywells, rain gardens, or other systems.
5
Grading & access for equipment. Getting excavators, concrete, and materials to a backyard build takes room. Tight side yards, fences, and slopes all affect how — and how affordably — the work gets done.
6
Trees. Mature trees are protected in many areas and their root zones limit where you can dig. A single tree can move the whole footprint, so we map it early rather than discover it late.
What an ADU can do for you
The reason to work through all of that is what the finished unit makes possible. An ADU is one of the few home investments that can pay you back in cash, in flexibility, or in the ability to keep family close — and often in more than one of those at once. It adds a genuinely independent living space to property you already own, which is a durable form of value that grows with your neighborhood.
Rental income
A separate unit can generate ongoing income, whether long-term or as a furnished space, subject to local rules.
Multigenerational living
Room for adult children, in-laws, or extended family close by, with independence for everyone.
Aging parents
A single-level, accessible home lets parents live nearby with dignity — near enough to help, private enough to feel their own.
Home office & flex space
A dedicated, quiet workspace or studio detached from the main house — and an asset that adapts as your needs change.
We keep the investment conversation honest. Rather than promise a return figure, we help you weigh the real trade-offs for your lot and goals — construction cost against likely use, and what the added, independent square footage means for your property over the long run.
Designing small so it lives big
A great ADU doesn't feel like a compromise. The square footage is modest by design, so every decision has to earn its place — and that constraint is exactly what makes small-footprint design satisfying to get right. The difference between a cramped unit and one that feels like a real home is almost entirely in the planning.
Ceiling height does more for a sense of space than floor area, so we push it where the design and the height limits allow. Storage gets designed in from the start — built-ins, under-stair space, and tall cabinetry — instead of stealing from rooms later. Natural light is the other multiplier: well-placed windows and glazed doors make a compact space feel open and connected to the yard, and they cut how often the lights need to be on.
When the unit is meant for aging parents or long-term flexibility, we plan for single-level accessibility from the outset — a no-step entry, wider passages, and a bathroom that works with a walker or wheelchair. Designed in early, these choices are nearly invisible and add real longevity to the home. Retrofitted later, they're expensive and rarely as clean.
Common questions about building an ADU
Can I build an ADU on my lot?
Often, yes — but it depends on your zoning, lot size, setbacks, and utility connections, and the rules differ between Portland OR and Clark County / Vancouver WA. Rather than guess, we research your specific parcel and confirm what's buildable before any design work begins.
Can I rent it out?
In many cases an ADU can be rented, whether long-term or as a furnished unit, but occupancy and rental rules vary by jurisdiction and change over time. We confirm the current rules for your address so you can plan around what's actually allowed, not what used to be.
Is a garage conversion cheaper?
Sometimes. Reusing an existing footprint and foundation can save money compared with building new — but garages weren't built as living space, so insulation, moisture, ceiling height, egress, and bringing everything to code can offset the savings. We scope it honestly before you assume it's the budget option.
How long does it take?
The build itself is only part of the timeline. Feasibility, design, and permitting come first, and permit review times vary by jurisdiction. We give you a realistic schedule once we've confirmed your lot's requirements, and our own project managers keep it on track from there.
How do people finance an ADU?
Many homeowners finance an ADU rather than pay out of pocket. We offer financing through Lend Home Improvement with $0 down and no prepayment penalty, so you can move forward without draining savings and pay ahead whenever it suits you.
Start with a lot-feasibility check, not a floor plan
Before you fall for a design, find out what your property can actually support. Book an ADU consultation and we'll research your specific lot — zoning, utilities, and site conditions — so you know what's buildable before you spend a dollar on drawings.
Why JDI
The Right Choice for Your Home
Free, No-Pressure Estimates
Clear, upfront pricing with zero hidden costs.
18+ Years of Experience
Local craftsmanship serving Vancouver and Portland since 2007.
Top-Quality Materials
Designed for beauty, built for lasting durability.
Fully Licensed & Insured
Confidence and protection every step of the way.
Clean, Respectful Crews
We treat your home like it's our own.
Limited Time
$1,500OFF
Kitchen or Bathroom Remodel
Transform your space with expert craftsmanship. Free design consultation included.
Claim OfferExpires Oct 31
About Us
Contact Us
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April 30th, 2025 by Art Kulch
How we work
Our 3-Step Remodeling Process
From first call to final walkthrough, we handle every detail so you can focus on enjoying your new space.
Get in Touch
Reach out to us online or give us a call to schedule your free consultation. Our team is here to discuss your home remodeling needs and give you all the information you need.
- Personal Consultation
- What to Expect
- Detailed Estimate
Kickoff the Design Phase
Once you sign the design agreement, our design team will meet with you to discuss your priorities, goals, and design style for your home remodel project.
- In-Depth Design Consultation
- Design Development
- Design Finalization & Budget
Start Your Project
We'll kick off with a pre-construction meeting to outline logistics and expectations. Our design team hands over all details to the construction crew, and a dedicated project manager becomes your main point of contact.
- Portal Access for Updates
- Construction Phase Coordination
- Final Walkthrough
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Other Service Areas
- Battle Ground
- Beaverton
- Brush Prairie
- Camas
- Fairview
- Felida
- Forest Grove
- Gresham
- Happy Valley
- Hazel Dell
- Hillsboro
- La Center
- Lake Oswego
- McMinnville
- Milwaukie
- Orchards
- Oregon City
- Ridgefield
- Salem
- Salmon Creek
- Sherwood
- Tigard
- Troutdale
- Tualatin
- Vancouver
- Washougal
- West Linn
- Wood Village
- Woodland
- Yacolt
More services in Portland
ADU building guides
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Everything here can be verified.
JDI Construction NW LLC is a licensed and insured design-build remodeler headquartered at 1419 Broadway Street in Vancouver, WA. Look up our licenses, read what past clients wrote, and see the work before you call.
Washington licenseJDICOCN932KZRegistered with WA Labor & Industries.Verify with L&I →Oregon licenseCCB 176101Oregon Construction Contractors Board.Verify with the CCB →Google reviews4.9 / 5 from 223+ reviewsAcross our Vancouver and Portland profiles.Read the reviews →Warranty5-year written workmanship warrantyOn every remodel we build.Read the warranty →The teamFamily-owned since 2007Meet the designers, consultants, and project managers.Meet the team →Our workReal JDI projectsPhotos and details from completed remodels.Browse projects →
Get started
Take the First Step with Portland ADU Builder Today!
Discover the incredible potential of your property with Portland ADU Builder. Get in touch now to start your journey with us!
- Get in TouchA personal consultation and a detailed estimate.
- Kickoff the Design PhaseDesign development, finalization, and budget.
- Start Your ProjectA dedicated project manager and portal access for updates.
Prefer to talk?(360) 309-9571
Service area
Based in Vancouver. Serving Clark County & the Portland metro.
Headquartered at 1419 Broadway Street, Vancouver, with a Portland meeting office by appointment. No franchises; our in-house crews drive to every project from here.
