Portland has been building ADUs longer than almost anywhere in the country, which means the code is well-trodden and the housing stock is not. Basements with 6-foot-8 ceilings, galvanized supply lines, 100-amp services and historic overlays are the real variables. Serden Group runs feasibility on all of it, submits a package built to survive plan review, and delivers the unit to a certificate of occupancy under Oregon CCB #239429.
The Portland ADU conversation is rarely about whether it is allowed — it usually is. It is about four things the house will tell you only if someone looks. Whether the basement has the ceiling height and the egress well a bedroom requires. Whether the electrical service can carry a second dwelling. What the system development charges total under the rules in force the month you permit, since Portland's ADU waiver programs have come and gone. And whether a historic or design overlay is going to shape the roof form of a detached unit. We answer all four in feasibility, in writing.
Detached units, attached units, above-garage builds, and basement and garage conversions across Portland's east side and close-in west side. Feasibility, engineered plans, Portland Permitting & Development submittal, site work, utilities and finishes under one contract.
A standalone unit in the back or side yard on its own foundation — kitchen, full bath, bedroom, and its own entry and address.
Built off the existing house on a new footing line, with a separate exterior door and a code-compliant separation wall.
Converting space you already own — insulation, egress, ceiling height, a new kitchen and bath, and a legal second address.
A second story over an attached or detached garage, with the foundation and shear capacity verified before design starts.
Portland zoning decides most of this before design does. We check your base zone and any overlay — historic, conservation or design — against setbacks, building coverage, height and floor-area limits, and we assess whether your existing foundation and framing can carry a second floor. You get a clear go, a build-out-instead recommendation, or a no, with a realistic budget range.
Floor plans, elevations and stamped structural drawings, then submittal and plan-review management through Portland Permitting & Development. Projects in historic or design-overlay districts get the additional review built into the schedule up front, so the timeline you are given is the timeline you actually experience.
Foundation and shear upgrades where the engineer calls for them, framing, roof tie-in, mechanicals, then finishes — sequenced to keep the house weather-tight on an infill lot with almost no staging room. One project manager, daily progress, and a punch-list walkthrough before final inspection.
Why Homeowners Choose Serden
Homeowner Stories
Real reviews, quoted word for word from the sites our clients left them on. Every card links back to that site.
Across 400+ reviews on 9 platforms
Also rated on Houzz, Facebook, Nextdoor, BBB (A+ rating) and Networx.
Read all 400+ reviewsThe project was finished on time and within budget. There was outstanding communication from start to finish and meticulous attention to detail. They are a contractor that goes the extra mile and I would definitely recommend.
Fantastic experience! They renovated my entire home with new floors, a full kitchen remodel, and a bathroom upgrade. The kitchen looks amazing with new cabinets, countertop, and appliances, and the bathroom to shower conversion turned out beautifully. Great quality work, finished on time, easy to communicate with, and their pricing was very competitive. Highly recommend!
We were very happy with the workmanship on our upstairs, downstairs and stairs flooring. Very friendly and were very accommodating to our home schedule and would recommend them to anybody who needs work to be done in their home
Serden remodeled our kitchen, dining room, living room and entry way. Dennis and Alex were especially friendly and easy to communicate with. Every person we had contact with was professional and did quality work. When unexpected issues came up, they solved the problems efficiently so we didn't have to stress about anything. They worked really hard to make sure we were happy at each step of the process. We love our new living space!
I purchased my first home a couple years ago, which was a time capsule from the 60s/70s. I got multiple quotes on getting my house updated. I of course wanted the updates to be budget friendly, but quality enough to last for years to come. Serden Group helped make suggestions that saved me money (to no benefit to themselves). With some of the other quotes I received I couldn't understand where so much of the cost was coming from and the quotes themselves were not clear in what I was being charged for. Serden Group however was very transparent in their pricing. The work they did is absolutely beautiful. Communication was consistent and timely. Their crew is incredibly kind and professional and cleaned up everyday. I think the scariest thing for most people getting work done our their homes is finding a trust worthy company to do so. There are too many occasions of companies having inflated pricing, hidden expenses, shoddy work, or poor communication. If you're looking for a company you can trust and to treat your home with the best care, give these guys a call.
We have used Serden Team for 3 projects. They remodeled our master bedroom and bathroom, refaced kitchen cabinets and built a beautiful surround for my refrigerator so it looks built in and remodeled a secondary bathroom. Their work is fantastic. They are easy to work with and communication is the best. I can trust them to do a great job and do the work properly the first time. Wonderful company and will refer them gladly.
They did an excellent job. They were fast and professional. They installed all new doors throughout my house, raised the floor in my family room and office, installed new flooring, and painted both rooms. It looks wonderful. I will be so happy to use the rooms once everything is put back where I want it. We have more work we want done in the future and I will definitely be hiring these guys again.
Serden did a great job on my vacation home in WA. They transformed the property, I had all my floors and windows changed out. Everything looks beautiful, up to date and modern. I will be using them again to remodel my kitchen and bathroom. The whole experience was easy and quick.
We hired Serden and their team to do a complete remodel of our new home that was very outdated. The work they did was incredible! They were very professional, timely, and the attention to detail on the work is amazing. We are so impressed and highly recommend!
Thank you for your quick response. Also, a big Thank You for helping me make my dream house come true, I never expected my home to become so beautiful. Great job. I will recommend you to my friends.
Serden Group and their crews Had done an awesome job remodeling my house. I am very pleased with the outcome. They were very professional and on time. I would definitely use their service again and recommend them to families and friends.
The remodeling team from Serden Group did a very good and professional job at my home. They completely remodeled the kitchen and all the dining and living areas, everything looks like a brand new home! They also installed new patio cover and deck which we already enjoy. Thank you! I definitely recommend them, they are experts, friendly and know what they are doing.
Serden Group remodeled kitchen and all bathrooms in my house. I am very happy with the quality of their work and the way they were informing me on every stage of the project. They also provided design ideas and suggested colors and materials. I needed the full service from design to completion. I am very satisfied.
Cannot be happier with the outcome of our remodel! Professional and communicative contractors. We will go back to Serden for all of our remodeling needs, other contractors do not compare. Yes- we have wasted time and money on others, before finding Serden.
I recently worked with Serden Group on my condo renovation, which included replacing floors, removing popcorn from ceilings, and replacing kitchen counters and cabinets. I loved working with Dennis and David. Dennis helped with input on the kitchen design and was great in helping to reduce stress. They were patient with me and my questions. Their crew was great. And as messy of a job that it was, they managed to leave the place clean when they left for the night. The work was great, and they care for the space as if it;s their own.
This company did a great job on an extensive remodel of a mid 70s home. They upgraded the electrical, plumbing, removed walls, remodeled the bathrooms and kitchen, and put in all new tile flooring. All the home issues were addressed, and we could not be any happier.
Portland allows ADUs broadly, and then the specifics of your lot and your century-old house decide the project. Here is what we plan for.
Building, plumbing, mechanical and electrical permits all run through Portland Permitting & Development, and plan review is the dominant schedule variable — 12–20 weeks is normal, longer where design or historic review applies. We submit a complete package rather than a fast one, because a second correction cycle costs more calendar time than getting the first one right.
Portland assesses one-time SDCs for water, sewer, transportation and parks when a dwelling unit is added, separately from the building permit. Portland has offered ADU waiver and exemption programs at various points, each with conditions and an expiration, so whether one applies depends on the rules in force when you permit. We quote the current schedule as its own line and never assume a waiver.
Alberta, Irvington, Ladd's Addition, Laurelhurst and other districts carry review that applies to new exterior construction — which a detached ADU is. It shapes roof form, siding, window proportion and placement, and adds weeks at the front of the schedule. Entirely workable, as long as it is in the plan from day one.
Basement conversions in Portland's bungalows and four-squares regularly surface 6-foot-8 ceilings that need a lowered slab, egress windows that need a new well cut, galvanized supply lines at the end of their life, knob-and-tube wiring and a service too small for a second dwelling. We inspect for all of it in feasibility and carry a written allowance.
Portland ADU standards, permit requirements and system development charges change, and waiver programs expire. Verify current requirements with Portland Permitting & Development for your address — we handle feasibility, submittal and inspections either way.
From Alameda, Irvington and Laurelhurst to Sellwood, Mt. Tabor, Beaumont-Wilshire and St. Johns — Serden Group builds additions across Portland’s older neighborhoods and the surrounding metro. We know which streets sit inside historic and conservation districts, and what that adds to review.
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Three tiers cover most of what we build in Portland. Every figure includes design, structural engineering, permits, construction and finishes; system development charges are quoted as a separate line. Oregon charges no sales tax.
Ranges are planning figures, not quotes. Your fixed price comes after feasibility, a site visit and a written scope.
East side, close-in west side, and the inner suburbs.
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The services that pair most often with an ADU, plus the planning guides our Portland clients read first.
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