Home Additions in the Seattle–Tacoma area
When your family has outgrown its walls but not its neighborhood, an addition lets you stay rooted where you belong. As 5th-generation builders headquartered in Milton, we design and construct additions of every kind — master suites, sunrooms, expanded kitchens, second stories — that look and feel as though they were always part of your home.
The overview
Our approach to home additions
An addition is one of the most rewarding investments a homeowner can make, and one of the most demanding to get right. Matching rooflines, tying new foundations into old ones, and weaving fresh framing into a structure that has settled for decades all require a builder who treats the existing house with as much respect as the new square footage. That is the standard our family has upheld across five generations of Pacific Northwest construction.
Because we are a true design-build firm, your entire addition lives under one roof — ours. Our in-house 3D design team models the expanded home before permits are ever filed, so you can walk through the new space digitally, refine finishes, and lock in a realistic budget early. From there, the same team that drew the plans manages Pierce County permitting, structural engineering, and every trade on site.
This page is your starting point. Whether you are weighing a single-room bump-out, a rear extension, a full second story, or a major multi-phase expansion, we will help you compare the options against your lot, your budget, and your long-term plans — and we offer financing assistance to make the numbers work.
A note from Donovan
Your home additions, treated like it's our own home.
I'm Donovan. My family has been building across the South Sound for five generations, and every home additions project we take on gets the same promise: an honest budget range, a design you can walk through in photorealistic 3D before we build it, and a crew that treats your house the way we'd treat our own.
You won't be handed off to a call center or a stranger with a clipboard. You'll work with the same family that's earned its reputation one neighbor at a time — and we don't consider the job done until it feels like home.
— Donovan
Owner & Lead Designer · Licensed WA #HOMERDB750MH
Free design consultation
Tell us about your home additions project and Donovan's team will reply within one business day — no obligation, just honest advice.
Why choose us
What sets our home additions apart
Every Addition Type, One Builder
Primary suites, in-law quarters, sunrooms, garage conversions, second stories, and full wing expansions — we plan and build them all, so you get honest guidance on which path fits your property rather than a pitch for the only thing a contractor knows how to do.
In-House 3D Design
Our designers model your expanded home in photorealistic 3D before construction begins, letting you test layouts, window placement, and finishes while changes still cost nothing but a conversation.
Seamless Structural Integration
We engineer foundations, framing, and rooflines so the transition between old and new is invisible — no awkward steps, mismatched siding, or telltale seams.
Permits and Code, Handled
From Milton zoning and setback rules to Pierce and King County inspections, our team manages the entire regulatory path so your project never stalls at a counter.
Five Generations of Craft
Licensed under HOMERDB750MH, we bring a century of family building standards to every beam, flashing detail, and finish nail.
Financing Assistance
We help you explore renovation financing options so a well-built addition fits your monthly budget, not just your wish list.
How it works
Our design-build process
Discovery Consultation
We walk your property, listen to how your household actually lives, and identify which type of addition delivers the most value for your lot and goals.
Design & 3D Visualization
Our in-house team develops floor plans and photorealistic renderings, refining them with you until the design feels unmistakably yours.
Engineering & Permitting
We finalize structural drawings, coordinate any required engineering, and submit permits to the appropriate jurisdiction on your behalf.
Construction
A dedicated project manager runs the build day to day, sequencing foundation, framing, weatherproofing, and finish trades while keeping your home livable.
Final Walkthrough & Warranty
We inspect every detail with you, complete the punch list, and stand behind the finished addition the way five generations of builders always have.
When the tools come down and the crew heads home, what's left is yours — a house that finally feels like home.
Donovan& the crew
Start your home additions projectFAQs
Home Additions questions
How much does a home addition cost in the Seattle–Tacoma area?
Most additions in the Seattle-Tacoma region range from roughly $150,000 for a modest single-room expansion to $400,000 or more for large suites and second stories. After our initial design meeting we provide a detailed estimate tied to your actual plans, and we offer financing assistance to help structure the investment.
Which type of addition adds the most value?
It depends on your home and lot. Extra bedrooms and bathrooms typically deliver the strongest resale returns, while primary suites and expanded kitchens transform daily livability. During discovery we compare options against local market data before you commit to a direction.
Will the addition match my existing house?
Yes — that is the heart of our craft. We match or thoughtfully complement your rooflines, siding profiles, window styles, and interior trim so the finished addition reads as original construction, not an afterthought.
Can we live in the house during construction?
In nearly all cases, yes. Because most of the structural work happens outside your existing envelope, we typically keep the home sealed and functional until the final tie-in, which we schedule and communicate well in advance.
How long does an addition take?
Design and permitting generally run two to four months, with construction taking three to six months depending on scale. Your proposal includes a project-specific schedule before any work begins.
Do you handle design, or do I need my own architect?
You do not need to hire anyone else. Our in-house 3D design team creates the plans, and because designers and builders share one office, your vision survives intact from first sketch to final walkthrough.