An addition isn't a remodel — it's new construction joined to a house that's already standing. Serden Group handles the entire chain in-house: feasibility, engineered plans, permits, foundation, framing, roof tie-in, mechanicals and finishes. One licensed design-build team, one project manager, 1,500+ projects across Clark County and the Portland metro.
Outgrowing your house shouldn't mean leaving the lot, the schools, and the neighborhood you chose. A well-planned addition buys you the primary suite, the second full bathroom, or the ground-floor bedroom you actually need — without agent commissions, a double move, or a reset property tax basis. And because additions touch structure, zoning and every mechanical system at once, they reward one accountable team over a string of separate bids.
Bump-outs. Primary suites. Second stories. ADUs and garage conversions. Structural work, permits, framing, roofing, mechanicals and finish carpentry — sequenced by one project manager from feasibility through final inspection.
Kitchen and family room expansions, sunrooms, home offices, and ground-floor bedrooms — added on a new foundation line.
A true owner’s suite: bedroom, walk-in closet, and spa bath with the plumbing and HVAC properly extended.
Build up when the lot won’t allow out — shear walls, foundation upgrades, new stair, and a full roof rebuild.
In-law suites, garage and basement conversions, and detached ADUs permitted as separate dwelling units.
An addition touches zoning, structure, weatherproofing and every mechanical system at once. Here's the full scope Serden Group coordinates — our own crew on the build, plus licensed, vetted trade partners for engineering and specialty work.
Setback, lot coverage, height and easement review against your zone — before you spend a dollar on design.
Stamped drawings for footings, beams, headers, shear walls and load paths — required on nearly every addition.
Excavation, footings and stem walls, floor system, wall framing and roof structure tied into the existing house.
Matched pitch and overhang, properly flashed valleys, and siding and trim profiles that read as original.
Egress-compliant windows, house wrap, flashing and air sealing built for Pacific Northwest rain, insulated to WA and OR energy code.
Duct or mini-split extension, panel capacity review, new circuits, and plumbing rough-ins for new baths and kitchens.
Wall texture matched to your existing rooms, continuous flooring runs, matched baseboard and casing, doors and built-ins.
Application prep, plan-review corrections, and every inspection managed through final sign-off.
Before you pay for design, we measure your lot against your zone's setbacks, lot coverage and height limits, and check whether your foundation and roof can carry what you want to build. You get an honest yes, a build-up-instead recommendation, or a no — plus a realistic budget range.
Floor plans, elevations and stamped structural drawings, then submittal and plan-review management with Clark County, Vancouver, Camas or Portland Permitting & Development. Every selection and every line of the schedule is approved before material is ordered.
Footings, framing, roof tie-in, mechanicals, then finishes — with your kitchen and bathrooms kept in service and the work zone sealed and dust-controlled. One project manager, one number to call, 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.
Finished, mid-range attached additions in this metro generally run $200–$400 per square foot. The ranges below are planning numbers for a permitted, fully finished space — not a quote. Your actual price comes off engineered plans after we see your lot and your foundation.
Second stories and any structural reinforcement of the existing house. New kitchens and bathrooms. Sloped or rock-heavy lots. Moving a service panel or upsizing it. Sewer and stormwater work. Historic or design-overlay review in Portland.
Building out on a flat, open lot. Keeping the addition on one plumbing wall. A simple gable that ties into the existing roofline. Converting space that is already under roof, like a garage or basement. Reusing your existing HVAC capacity where it can carry the load.
Structural engineering, permit and plan-review fees, and system development charges tied to added square footage. Stormwater management when a project disturbs enough impervious area. Landscaping and fence repair where equipment had to reach the work.
These three get quoted against each other constantly, and they solve different problems. Here's the honest comparison — including when an addition is the wrong answer.
New square footage joined to your house, sharing its kitchen, entry and utilities.
Best when you need
A separate legal dwelling with its own kitchen, bath and entrance — attached, above a garage, or detached.
Best when you need
Different permit path and utility work. See our Clark County ADU permit guide.
Reworking the space you already have — layout changes, finishes and systems, same footprint.
Best when you need
Often the smarter call on a tight lot. See full home remodeling.
If your lot has no room inside its setbacks, your zone caps lot coverage below what you need, or reworking the existing layout would get you 80% of the result for half the cost, we will tell you that at the feasibility stage — before you have paid for design.
They solve the same problem — not enough room — in opposite ways. One adds a floor on top of the house; the other pushes a wall outward. The lot, the structure and how much space you need usually decide between them.
A new floor — or a partial floor over one wing — built on top of the existing house, reached by a new stair.
What it involves
An engineer traces the load path from the new floor down to the footings and specifies what has to be strengthened: often shear walls, new posts and beams, and footing upgrades. The existing roof comes off, the new floor is framed and dried in, and a stair is fitted into the plan below, which takes floor area from the existing rooms.
Best when
The lot has no room inside its setbacks or coverage limits, you need several rooms (a primary suite plus bedrooms), or you want to keep the yard.
Plan for
The longest build of any addition type, and a period when the house is open to the weather. Most families move out for at least the roof-off phase. Plumbing, ducting and wiring have to be routed up through the existing floor. On our planning table above, this is the highest-cost row.
An exterior wall pushed outward to enlarge one room — a kitchen, a primary bath, a dining area or a closet.
What it involves
Larger expansions sit on a new footing and tie into the existing floor and roof. Some small bump-outs can be cantilevered off the existing floor framing, but only within limits the engineer sets for the joists and the span. Either way, the opening in the existing wall usually needs a new header, and the roof and siding have to be tied in so the change reads as original.
Best when
You need more space in one specific room, the lot has room inside its setbacks on that side, and the existing layout mostly works.
Plan for
The room being expanded is out of service while the wall is open. Gains are modest — the planning table above sizes bump-outs at 80–200 sq ft — so check that a few feet actually fix the problem before committing.
Setbacks and lot-coverage limits decide whether building out is possible at all; height and floor-area limits decide how far up you can go. We check both against your zone at feasibility.
A second story depends on the existing footings and framing; a bump-out depends on the wall it opens and the floor it extends. Both need an engineer's review before the design is final.
Will the existing foundation need work? Where will the stair go? Will we need to move out, and for how long? What is excluded from the price — engineering, permit fees, utility charges? Is reworking the existing layout a cheaper fix?
Converting a garage instead? Our garage conversion cost guide covers scopes and cost drivers. For Portland bungalows, see home additions in Portland.
Serden Group builds additions on both sides of the Columbia — bump-outs on Clark County's newer subdivisions, primary suites on Camas hillside lots, and second stories on Portland's older bungalows. Setbacks, lot coverage, stormwater and design review differ in every one of these jurisdictions, and we have permitted work through all of them.
Request your free home remodeling consultation
Please select an option to continue.
Questions? Call (360) 836-7775
Blog posts will appear here.
Full project gallery will appear here.
Save up to
on your remodel when you call today
Call Now — (360) 836-7775Terms & restrictions apply | Offer valid for projects over $10,000
