Meta All Microsites Pixel

The 16 Best Home Addition Contractors in Seattle, Washington

27 Min Read

Seattle is the jewel of the Pacific Northwest. Home to several tech companies such as Amazon and Microsoft, `its economy is large and expected to grow into the future. Beyond its financial and economic stability, Seattle is an astonishing city because of its mountainous skyline, evergreen forests, and large parklands. The city is environment-friendly and it has a good education system with public and private schools for primary and secondary education as well as the University of Washington and several private universities. Seattle is consistently ranked as one of the best cities to live in in the country, attracting people from around the state and across the nation. Seattle is widely known for its beautiful skyline. Striking buildings across the city add to the magnificent views framed by Seattle’s mountains and evergreens. If you are a Seattle area homeowner who would like to add space to your home, we suggest you check out this list of the best home addition contractors in Seattle, Washington. These firms can bring your vision of your home into reality while sticking to your budget and your timeline. Adept in planning and construction, these firms and their expert partners can customize your home to fit your needs, match your style preferences, and work within your budget. Read on and see how your home can add to the beauty of the Seattle skyline.

Sockeye Homes

14638 SE 229th Place, Kent, WA 98042

Sockeye Homes is a multi-award-winning custom home builder and remodeler. The firm holds the record for the most state-wide Excellence in Remodeling Awards received in a year–it received nine awards in 2012. In 2020, the firm was awarded the prestigious Chrysalis Decade of Excellence award – a national award that attests to the firm’s time-tested excellence in construction and design. The firm’s founder and president, Tod Sakai, is a Washington State Certified Builder and holds Certified Graduate Builder and Certified Graduate Remodeler designations from the NAHB. His mastery in construction, design, and project management leads the firm in delivering superior projects that exceed client expectations. Established in 2007, the firm has completed hundreds of custom homes, remodels, and additions in King County and adjacent areas. Its excellence in its craft is marked by a unique eye for combining elements and styles to match homeowners’ unique tastes and lifestyles while fitting into the specific context of the home. For home addition projects, this involves merging new parts with the existing structure to create a seamless flow between the old and the new.


In the home addition project featured above, Sockeye reframed the roof structure and worked within the existing square footage of the home to create a great room concept, complete with high ceilings and modern interior and exterior designs. The new space offers a much more open and airy ambiance that maximizes natural lighting while offering a great view of the outdoors. The firm’s design creates an urban feel that complements the nature-filled wooded neighborhood of Bridle Trails.

CRD Design Build

3929 Stone Way N, Seattle, WA 98103

CRD Design Build is a design-build firm that offers kitchen, bathroom, basement, and whole-home remodels and additions. Founded in 1980, the firm was one of the first in the city to utilize the design-build approach by working in concert with architects and designers throughout the entire project process. This led to better coordination between the project plan and actual construction and ensured that schedules and budgets were followed with more accuracy. Grounded on the ideals of creativity, integrity, and care, the firm helps clients improve their homes in both function and beauty while staying within time and financial limits. CRD strives to upgrade homes at least cost and with maximum efficiency so that clients can stay in the homes and neighborhoods they love. Founded in 1980, CRD Design Build has helped Seattle homeowners transform their homes to fit their needs and lifestyles. The firm helps clients visualize their new home through 3D visualization, offers fixed pricing, delivers on time and within budget, and provides a 24-month warranty. Through these guarantees, CRD delivers beautiful, functional, and durable homes that clients can enjoy for a long time.


In the home addition project featured above, the homeowners wanted to remodel their 1930s home to add more space and upgrade several home functions. As the home was surrounded by redwoods, the best course of action was to expand upwards. CRD designed and built the home’s second story, which features three bedrooms and a bathroom. The firm also repainted the entire home and added heating to all the floors. CRD’s work improved the home’s functionality and space usage while retaining the traditional Cape Cod charm of the old home. The addition was completed seamlessly—the home looks as if it had always had two stories.

Built Square

4601 Shilshole Avenue, NW #5, Seattle, WA 98107

Built Square is a premier award-winning remodeling and construction company that offers home additions and remodels of bathrooms, kitchens, basements, and entire homes to homeowners in the Seattle metropolitan area. Established in 2008, the firm aims to deliver carefully crafted beautiful homes that meet clients’ needs and goals while protecting the existing natural and architectural environment. The firm achieves these goals through regular communication, thorough planning, and careful choices in design elements and styles. The firm’s team members are experts in their craft and take all necessary steps to ensure clients that their newly constructed or remodeled home is safe, environment-friendly, long-lasting, and beautiful. Over the past 13 years, Built Square has received numerous awards, and it has been recognized in several publications for its excellent work and outstanding customer service. The testimonials of its clients also attest to the firm’s commitment to client satisfaction through its honest and exemplary work.

Built Square

In the Seattle home project pictured above, Built Square added a third-level master suite to the home for increased privacy for the homeowners and to add space on the main floor for entertaining. In order to retain the modern home style and ease movement inside the home, the firm switched the direction of the staircase through all levels. The firm also upgraded all existing electrical, plumbing, and heating systems to enhance the home’s safety, durability, and efficiency. The remodel improved the home’s space usage, functionality, and safety and offered better views of Lake Washington and Mount Rainier. Built Square’s work created a balance between modern style and nature via its excellent craftsmanship.

Irons Brothers Construction

1510 NE 170th Street, Suite #2, Shoreline, WA 98155

Irons Brothers Construction is a family-owned multi-award-winning construction firm that serves homeowners in the North Seattle area. It offers whole-home construction, home additions, kitchen and bathroom remodels, custom carpentry, and fine tile work. Grounded on the mission of delivering creative and custom designs through an exceptional building experience, the firm provides clients quality craftsmanship and superior customer service. Its efficient and systematic design-build process allows the firm to transform each client’s vision into reality using local, sustainable materials and efficient methods. Its dedication to its craft extends from delivering beautiful and efficient homes to protecting the natural environment and maintaining the beauty of the region’s architectural landscape. As a local builder with decades of experience and involvement in the homebuilding industry in the region, Irons Brothers has formed a trusted network of suppliers and subcontractors. That network allows the firm to offer a wide range of material and design selections to its clients.

Irons Brothers

TIn the home addition project featured above, Irons Brothers added three stories and an elevator to an old single-story home. The existing home for this project was outdated and lacked adequate space for the family and the occasional guest. The homeowners opted to expand vertically to add more space without tearing down the existing flora surrounding the home. Irons Brothers improved and modernized the home using contemporary materials that improved natural lighting and interior heating while creating a sleek modern look on the outside. Adding an elevator eased access between the floors and will help the homeowners age in place. The firm improved the home’s aesthetics, functionality, and efficiency while enhancing the excellent view from the back.

Prestige Residential Construction

1200 S Angelo Street, Suite A, Seattle, WA 98108

Prestige Residential Construction is a local construction firm that specializes in custom home construction, room and home remodels, and home additions. Founded in 1981, the firm has worked with homeowners, designers, and architects in building and transforming homes. The results are consistently beautiful, functional, and durable. The firm’s portfolio includes both modest and large-scale remodels, historic renovations, and new builds for clients across the greater Seattle area. The key to its excellent work and success is its precision craftsmanship philosophy, which guides the entire process from planning and budgeting to construction and project management. Each of the firm’s team members brings in unique expertise and plenty of experience. That combined experience and skill allows the firm to create exquisite designs, efficient plans, and systematic construction. The firm is true to its name in delivering the highest quality project regardless of project scope, size, or budget. In its decades of service to Seattle residents, Prestige has worked on different home sizes and styles – from traditional and cottage style homes to contemporary and mid-century modern designs. Its extensive knowledge in architecture and design allows the firm to work in any size lot while working on a wide range of architectural styles. It’s all about creating the best possible home to match both the surroundings and the needs of the client.


In the home addition project pictured above, the homeowners wanted major additions to their home that matched the expansive size of the lot. Since the project required the construction and modification of several structures, the homeowners and team members opted to conduct the project in phases. The first phase involved a 1,500-square-foot two-story addition to the main home; the second phase involved a new 1,000-square-foot covered porch and porte-cochere; the third phase involved transforming the basement into a multi-purpose media room and wine cellar. The firm also improved the exterior and greenery to match the new additions. The resulting home presents a quaint, classic exterior and a high-tech luxurious interior.

Pathway Design & Construction

PO Box 94731, Seattle, WA 98124

Pathway Design and Construction is a Seattle-based full-service home remodeling company that specializes in universal design and healthy, green building. The firm’s emphasis on universal design ensures clients that their homes will be versatile, functional, and comfortable; its focus on green building principles ensures safety and sustainability. Clients can be assured that their homes promote wellness practices in their everyday lives and that the air and water inside their homes are at optimal levels for good health. This dedication to ensuring the safety, security, and wellness of clients is at the core of Pathway’s work in construction and design. The firm balances all these measures and works within the client’s budget and schedule to build a home that addresses client needs, sustainability, safety, and structural durability. That commitment to expert craftsmanship and client wellbeing has earned the firm several local, regional, and national awards. Since its founding in 2008, the firm has completed numerous bathroom and kitchen remodels, condo renovations, whole house constructions, and home additions. Regardless of size and scope, the firm aims to optimize its design and construction to offer clients the most healthy and energy-efficient home they can afford.


In the West Seattle home addition project pictured above, Pathway, along with design work done by Live-Work-Play Architects, completed a two-story addition that increased the home’s space and revolutionized its overall look and feel. The large windows opened the interior to more natural lighting and created a better home ambiance. The wrap-around deck with glass panel railing in the master’s suite and main floor offers a great view of the Seattle skyline and has become the perfect spot for family time and the occasional gathering. The choice of materials, such as the Marvin aluminum-clad windows and doors and the Mitsubishi ductless heating system, improved the home’s security, safety, and air quality. The home addition resulted in a transformed energy-efficient home that the family will enjoy for years to come. Learn more about their work at

Ventana Construction

5958 California Avenue SW, Seattle, WA 98136

Ventana Construction is a construction firm that specializes in custom homes, home remodels, and home additions. Following their mantra—imagine, build—the firm coordinates closely with clients and their architects to create an image of their perfect home and carefully plans the entire project before starting the actual build. The firm assists clients in the planning stage by giving experience-based knowledge on potential costs, material availability, and logistical needs. During construction, the firm regularly communicates the project’s progress to clients, keeping them updated and providing complete transparency. The firm is owned by husband-and-wife tandem Clarence and Anne Higuera—a master carpenter with over 40 years of experience and a certified remodel and ageing-in-place specialist. They guarantee excellent craftsmanship and professionalism, matched with compassion for homeowners’ love and care for their homes.


In the kitchen and living room addition project featured above, Ventana remodeled and added an old 1920s bungalow to a more modern home with a classic look. The main floor of the old home was dominated by small rooms, which made it appear even smaller and darker. Ventana opened the space by eliminating some interior walls and adding two feet of space to the floor. The result created a more airy ambiance that allowed natural lighting to penetrate the space more evenly. The living room, instead of being bordered from the kitchen, blended naturally and created a better space for gatherings with family and friends. Ventana was able to retain the traditional 1920s looks of the home while improving the main floor to fit the needs and lifestyles of the homeowners.

Dyna Builders

1537 NW Ballard Way, Seattle, WA 98107

Dyna Builders is a residential and commercial construction firm specializing in design, rebuilding, and homebuilding. Established in 1999, the firm works on modest to large scope projects for clients throughout the greater Seattle area. Core to the firm’s success in each project is its focused attention to detail and expertise in metallurgy. Its custom fabrication shop, Dyna Metal, allows the firm to design and fabricate customized pieces such as railings and fireplace surrounds that are tailored for specific spaces. This capability allows the firm to utilize other materials with more flexibility and subsequently offer clients more unique designs and one-of-a-kind pieces that match their needs, styles, and personalities.


As a Certified Passive House Builder and a Seattle Area Built Green Member, Dyna promotes environmental protection, energy efficiency, and connection with nature. In the Phinney residential addition project pictured above, the firm utilized eco-friendly materials and improved the home’s energy efficiency. The third-story addition added a master suite to the modern home. The firm installed floor-to-ceiling windows and sliding doors to maximize the view of the Seattle skyline to create a seamless transition between the interior and exterior space. The choice of materials and placement of specific features resulted in the perfect build—everything was as it was imagined by the homeowners.

Mighty House Construction

3108 SW Webster St., Seattle, WA 98134

Mighty House Construction is a full-service general contracting firm that serves clients in the greater Seattle and East Side areas. Founded on the mission of providing innovative and sustainable building solutions at an outstanding value, the firm builds and remodels homes that are environment-friendly, functional, and beautiful—all while staying within budget. Co-founder Doug Elfline has a degree in interior design and over 20 years of experience in the construction industry. His knowledge and experience guide the firm in selecting the best subcontractors to work with on specific project types and scopes. He also helps clients select materials and designs that match their needs but are lower in cost. Co-founder Laura Elfline is a native Seattleite who has 15 years of experience in business and project management. She ensures clients that projects run smoothly and efficiently so that homes are turned over as designed on time and within budget. Together, this dynamic team has driven the firm to produce projects that are as beautiful as they are efficient.

In the Deep Green Westwood Addition project pictured above, the firm successfully constructed a second-story master suite and bath to a war-box home. As a means to increase comfort and movement for a growing family, the homeowners wanted to add more space to their decades-old home and to improve its aesthetics and durability at the same time. The firm built the second-story suite that let in ample natural lighting without disrupting sleep and used infrared radiant ceiling panels for an efficient heat source that went well with a soothing and relaxed bedroom feel. Mighty House used locally-sourced wood and recycled glass tiles in the remodeled kitchen and dining space for a fresh, inviting look. The firm also refurbished several of the existing exterior segments of the home and reused parts of the old front porch as the back to minimize resource and budget consumption. Mighty House’s excellent and creative craftsmanship resulted in a beautiful and modest classic home that is sustainable, efficient, and cost-effective. It will be enjoyed by the family for decades to come.

Gaspar’s Construction

300 S Lucile Street, Seattle, WA 98108

Gaspar’s Construction is a family-owned award-winning design-build firm that has been serving Seattle homeowners for over four decades. Founded on the mission of making a difference in people’s lives, the firm works closely with clients and other professionals to deliver custom homes, home remodels, and home additions. Its team of experts and a trusted network of subcontractors collaborate on projects to build the best home. They consider the best home to be one that fits clients’ needs, preferences, and lot size while staying within budget and schedule. Its partner suppliers and vendors allow the firm to offer clients a wide range of design, material, and color choices that fit the overall style and feel of their homes. Together with its partners, Gaspar’s multi-talented staff handles all sorts of home construction projects that guarantee excellent craftsmanship and client satisfaction.


In the Queen Anne kitchen addition featured above, Gaspar’s Construction transformed the home’s compartmentalized main floor with remodels and additions. The home’s main floor was originally divided into small disconnected spaces with a brick fireplace separating the areas. To facilitate better airflow and to ease movement between the areas, the firm took down the dividers and added four new beams to support the space addition. The resulting main floor shows a more open floor space and a seamless transition between the living room, kitchen, dining room, and deck. The home addition features a gas fireplace, a waterfall butcher block countertop for the built-in beer taps, and new countertops and appliances to match the contemporary look of the revamped living space. The project received the 2021 Excellence in Remodelling Addition over $250,001 award from the Building Industry Association of Washington (BIAW).

Hammer and Hand

2450 6th Avenue, Suite #100, Seattle, WA 98134

Hammer and Hand is a general contracting firm that serves clients in Seattle and Portland on both residential and commercial projects. Founded in 1995, the firm has completed dozens of new homes, commercial construction projects, remodels, and home additions. The firm’s team of expert carpenters and project supervisors use and optimize contemporary building science, precision craftsmanship, and modern project management tools to deliver projects that address clients’ needs. Those projects fuse well with the existing natural and architectural environment and fit clients’ budgets and timelines. Appreciating the need to protect the environment, the firm uses Passive House construction methods and designs to maximize a home’s energy efficiency, reduce its overall carbon footprint, and promote healthy living for homeowners and their families.

In the West Hills addition project pictured above, Hammer and Hand collaborated closely with clients and the architect to build a two-story luxury addition and a remodel of a 1920s Tudor-style home. The home, which already had three levels and a nice large backyard, needed additional space for the growing family. Despite the challenge of building on a hillside slope where there is little room for machinery, Hammer and Hand completed the addition and remodel seamlessly. The new addition included a magnificent new family room, an art studio, an extra bathroom, and a wine cellar. Using contemporary techniques and passive house methods, the firm deployed traditional materials and styles to retain the Tudor-style look of the old home. The firm’s excellent work resulted in a smooth transition between the spaces that retained the old charm of the home while adding the much-needed space for the family.

Proform Builds

111 West John Street, #300, Seattle, WA 98119

Proform Builds is a Seattle-based construction firm that offers new construction, remodels, home office build-outs, and home additions. The firm works in a wide range of home sizes and styles —from modest to grand and from cabin and ranch style homes to classic Queen Anne and more recent mid-century modern style homes. Core to the firm’s success is its passion for creating custom high-end homes that are as beautiful and luxurious as they are functional and comfortable. Since its founding in 2007, the firm has kept up-to-date with the latest construction techniques and innovative materials to better serve clients’ specific needs and requirements. Proform Builds creates a solid relationship with clients and banks on teamwork and a shared vision in working through the entire project process.

In the renovation and addition project pictured above, Proform successfully expanded an old home in a tight urban lot. The original home had a single story in a traditional Craftsman architectural style. To add more space for the growing family, Proform planned and built a three-story addition and renovated the main floor to fuse well with the addition. The firm reinforced the foundation and carefully chose materials and techniques to ensure the structure’s stability and the family’s safety. In keeping with the Craftsman style of the old home, the firm used hardwood on the floors and cabinetry while opting for classic steel on the appliances and accents. The combination of whites, blues, and grays in the interior create the traditional American family home feel that perfectly fits the growing family. Through careful planning and the use of new technologies, the firm completed the renovation and addition despite difficulties in the structure’s location and age.

JAS Design Build

3600 Wallingford Avenue N, Seattle, WA 98103

J.A.S. Design Build is a full-service firm that offers a wide range of design and construction services for homeowners in the greater Seattle area. Those services include new home construction, whole-house remodels, additions, accessory dwelling units, kitchens, bathrooms, basement remodels, cabinetry, interior furnishing, and handyman services. The firm’s in-house team of diverse experts and professionals allows J.A.S. to offer clients such detailed services with great efficiency and focused attention. Its collective passion for architecture and people drive the firm to deliver durable and creative homes that are as unique as their homeowners. Using a clear and practical approach to each project—regardless of scope and size—guides the firm in creating solutions that match clients’ needs and requirements as well as their resources and schedules. In designing and creating home additions, J.A.S. takes the time to carefully understand each homeowner’s preferences and lifestyle. Doing so allows the firm to collaborate with the client in defining what part of the home works and what does not; the firm then creates a construction plan to increase the home’s overall beauty, functionality, and efficiency.

In the Winander Warmth project, the firm renovated and added to the existing split-level house to create a Modern Farmhouse style home that offered more room for the family and the occasional gathering. Exposed beams and steel accents create a rustic charm that is both classy and inviting. The firm’s work added room for the growing family and created a warm and comfortable space for them to make memories for years to come.

Better Builders

4800 California Avenue SW, Seattle, WA 98116

Better Builders is a premier, award-winning residential builder that caters to clients in the greater Seattle area. It offers custom homes, home additions, room and whole-house remodels, and commercial tenant improvement. Driven by its mantra of creating beautiful and functional spaces for better living, the firm understands the goals and dreams of its clients and transforms these into exceptional homes of quality materials and efficient designs. As any home construction and remodel is both a financial and emotional investment, the firm assures clients—through careful planning and coordination—that projects are delivered on time and within budget and that they get to enjoy the entire building process. The firm also encourages and uses sustainable building methods towards enhancing the communities it works in and protecting the surrounding natural environment.

Better Builders

In the Queen Anne classic addition project pictured above, Better Builders used its expertise in various architectural styles and designs to complete a major remodel and addition while retaining the classic look of the home. The project involved a two-story addition on top of the existing basement garage to increase space for the family. The main floor addition enhanced the back porch with sturdier materials and shelter from rain and harsh winds. The second-floor addition added space for a larger master’s bedroom, bath, and a balcony. Large floor-to-ceiling windows and glass doors opened the new areas to maximize natural lighting without disrupting the home’s indoor air quality. To retain the Queen Anne architectural style of the home, the firm used a combination of brick and wood on the exterior siding with steel and metal accents and railings for the porch and balcony. The overall construction added more room, brightened up the entire home, and revamped the facade of the classic suburban home. The project landed the 2016 Rex award for Major Remodel Excellence for Partial House/Addition.

Harjo Construction

4900 15th Avenue NW, Seattle, WA 98107

Harjo Construction is a custom home builder and remodeler that specializes in innovative techniques and sustainable construction. Following its motto, “Transforming homes, improving lives,” Harjo strives to go beyond remodeling and building homes—it creates comfortable and safe spaces where people can live their best lives and create remarkable experiences. By focusing on honesty, integrity, and excellence, the firm collaborates with clients in establishing exemplary, yet realistic goals and creates foolproof plans towards reaching those goals. The firm’s team of expert builders and project managers work together to ensure that plans are communicated effectively and executed efficiently. Each project results in a home that meets the client’s requirements, budget, timeline, and—most importantly, a secure and sustainable space they will love and enjoy.


In the Loyal Heights addition and remodel project, Harjo added a second story to a 1940s Craftsman home and remodeled the main floor and basement to create an efficient home that matched the needs of the family. The firm transformed the basement to add a third bathroom, a laundry area, and a storage space while retaining the great room that can be used for gatherings. The former master’s bedroom on the main floor was transformed into a home office with a new bump-out fireplace as a main focal point. The new second story featured a loft, a third bedroom, and a generous owner’s suite. The use of vaulted ceilings throughout the rooms is characteristic of the Craftsman style and creates continuity from the exterior to the interior. New sidings, roofing, soffits, and trim revamped the exterior while retaining the classic Craftsman and adding a modern twist. The firm’s work resulted in an astonishing new home with a traditional look and feel.

Blue Sound Construction

10015 Lake City Way NE, Suite #301, Seattle, WA 98125

Blue Sound Construction is a Seattle-based general contracting and construction firm. It offers kitchen and bathroom remodels, second-story additions, custom home building, basement additions, house lifting and basement additions, and design-centric skilled carpentry. What sets Blue Sound apart from other firms is its philosophical take on architecture and construction. Beyond the science and artistry of interior design, architecture, and landscape architecture, the firm takes into consideration a structure’s influence on people and how they live their lives. Using this as a guide, the firm builds homes that are safe, durable, and functional, but also inspirational, enjoyable, and motivational.

Blue Sound

In the View Ridge two-story addition featured above, the firm carefully and successfully added vertical space to an existing contemporary home. To better design the home to the likings of the new homeowners, the firm scraped down the existing structure to its basement level and built the two above-ground levels. The firm went with a contemporary architectural style that matched the homeowner’s character and lifestyle and an open floor plan to offer versatility and flexibility in space usage across seasons and throughout the years. Quality materials and innovative designs create a sleek and modern look while numerous windows offer great views of Lake Washington. The use of both wood and steel and grays and browns on the exterior and interior create a remarkable contrast that is both classy and homey.