Home Addition Cost in Seattle, Washington ()
Home addition cost in Seattle, Washington ranges from $156 to $312 per square foot. Standard grade construction is represented by the lower end of this range and premium grade construction is represented by the upper end of this range. Luxury grade construction could be as much as twice the cost of the upper end of this range. To get a more accurate cost for your home addition project, request a quote. Please note that if you use our matching service, we may be compensated.
Topics Covered in this Guide: Home Addition Cost | Home Addition Cost Factors | Frequently Asked Questions | Related Cost Guides | Find Home Addition Contractors | Home Addition Cost in Your Area
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How Much Does Home Addition Cost in Seattle, WA?
Home addition cost in Seattle, Washington ranges from $156 to $312 per square foot. Standard grade construction is represented by the lower end of this range and premium grade construction is represented by the upper end of this range. Luxury grade construction could be as much as twice the cost of the upper end of this range. Consult with a contractor to discuss the pros and cons of different construction grades.
This guide is intended to provide you an approximate home addition cost in Seattle, WA. To get a more accurate quote for your specific project, request a free estimate. Our research, although general in nature, does include feedback provided by home addition contractors and research conducted by the HomeBlue staff.
Home addition cost based on the size of the addition:
- 12x12 addition cost (144-sf): $22,000 to $45,000.
- 20x20 addition cost (400-sf): $62,000 to $125,000.
- 20x30 addition cost (600-sf): $94,000 to $187,000.
- 20x40 addition cost (800-sf): $125,000 to $250,000.
- 25x40 addition cost (1,000-sf): $156,000 to $312,000.
- Note: The lower end of these ranges represents standard grade construction and the upper end represents premium grade.
- Note: Luxury grade construction in high cost areas could be as much as double the upper end of these ranges.
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Factors that Influence House Addition Cost in Seattle
When addition contractors come to your house to provide you an estimate, they will consider a number of factors that can increase or decrease the cost of your project. Pricing for your home addition project will vary based on the quality of construction you choose, the size of your addition, and the topography of the site. Here are a few things to keep in mind when you get quotes from house addition contractors:
Your prices may be higher when:
- You want premium or luxury grade construction.
- The addition requires a foundation.
- The property is historic and requires special approvals.
- The house is occupied.
- A basement needs to be dug.
- The site has a significant slope or is rocky.
- The property is in a hard to reach location (more travel time).
- The property is in a high cost area.
Your prices may be lower when:
- You want standard grade construction.
- No foundation is required.
- The house is vacant.
- The addition does not have a basement (it is constructed on-grade).
- The property is easily accessible (less travel time).
- The property is in a lower cost.
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Home Addition FAQs
Here are a few frequently asked questions related to home addition construction:
You can find home addition contractors in Seattle by 1) asking a neighbor for a referral, 2) searching for “home addition contractors” in your favorite search engine, 3) using a traditional paper directory resource (yellow pages), 4) looking for ads on your local TV station, 5) using an online matching service.
In general, hiring an architect or designer to prepare construction documents is likely necessary. The structural elements of the building will need to be designed and stamped by a licensed structural engineer. If you need to do foundation work, you may also need a civil engineer to make sure the site is properly graded. You can ask your builder if they could assist you with the design process (ie: do the project using a design/build approach) or whether they would prefer you hire an architect separately to prepare drawings. Either way, the final design documents will then need to be submitted to your local permit office for approval.
Building a home or an addition requires a contractor’s license in most localities. However, many localities provide exemptions when property owners choose to serve as the general contractor for a property that they own. You will need to research your local laws. For instance, here is a link to a Florida statute addressing owner-builder exemptions. There are pros and cons relating to serving as an owner-builder. For instance, you will assume many of the responsibilities and liabilities associated with the project.
It is highly likely that you will need a building permit to build a home addition. Discuss the permit process with the contractors you are considering for the project. A seasoned and reputable contractor should be comfortable and willing to help guide you through the process or willing to handle the task as part of their contract.
20x20 room addition cost in Seattle ranges from $62,000 to $125,000 depending on the grade of construction used. Standard grade will be at the lower end of this range and Premium grade will be at the upper end of this range. To get a more accurate cost for your specific project, request a quote from a local contractor.
12x12 room addition cost in Seattle ranges from $22,000 to $45,000 depending on the grade of construction used (standard is at the bottom end of this range and premium grade is at the top end of this range). To get a more accurate cost for your room addition project, request a quote from a local contractor.
The cost to add a second story in Seattle ranges from $156 to $312 per square foot depending on the grade of construction used (standard is at the lower end of this range and premium grade is at the upper end of this range). To get a more accurate cost, request a quote from a local contractor.
Related Cost Guides
We have researched several other closely related projects. If one of these projects better represents the type of project you are undertaking, please check out the appropriate guide:
- Building a new house? Home Building Cost Guide for Seattle, WA
- Building a barndominium? Barndominium Cost Guide for Seattle, WA
- Remodeling a bathroom? Bathroom Remodeling Cost Guide for Seattle, WA
- Remodeling a kitchen? Kitchen Remodeling Cost Guide for Seattle, WA
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Local Home Addition Contractors Near Seattle, WA
The following are a few contractors in your area. Note that these companies have not been screened or vetted by HomeBlue. Please conduct proper due diligence prior to hiring these or any other company you may select.
Levite Construction CO Levite Construction is a family owned Design, Build and Remodeling Company Based in Seattle WA. Our focus and determination are both solely centered around you, our client. Your satisfaction is what makes us thrive, and is the driving force that helps us to create and renovate the most beautiful homes. If you are looking for home remodeling in Seattle and the surrounding areas, Levite Construction is your premier choice.
Wise Choice Construction, LLC As one of the most populous cities in the country, finding the perfect home in Seattle can prove to be difficult. Instead of having to live in a home that's not really serving you, adding a home addition to increase the space is an increasingly popular remodeling project. Moving into a home that can be expanded upon opens up the opportunities to pick a location that you'd love to live in without sacrificing your standard of living.
Model Remodel Our experienced team has worked on dozens of award-winning projects and environmentally responsible homes in the Seattle area. It is our dedication to clients and exceptional craftsmanship that makes us who we are. Whether you just purchased your home or you’re making space for your growing family, let us guide you through the remodeling process. We know you’ll enjoy working with us as much as you’ll love living in your dream home.
Harjo Construction Harjo Construction is an award-winning remodeling specialist. We’re ready to listen and embark on this journey with you. Harjo Construction is an innovative residential remodeling and custom-building company. We are committed to harnessing the power of design to elevate our work and create homes that inspire passion. Since 2010, we’ve honed our skills and perfected our process by completing over 300 home renovation and construction projects in Seattle and around the Puget Sound.
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Find Home Addition Cost in Your Area
House addition cost varies from area to area. We have developed a number of home addition cost guides to help you identify the room addition cost near you.
- How to Get Home Addition Price Quotes
- How to Get Matched to Home Addition Contractors
- Search for Home Addition Cost in Your City
- Home Addition Cost Guide (National Averages)
- Home Addition Cost in Seguin, TX