What's the cost of a mudroom addition in Seattle?

Mudroom addition cost varies based on size, access, and finish level, but generally starts around $25,000–$40,000. Unique Home Construction designs for both function and weather durability, including built-ins, flooring, and energy-efficient entry solutions.

Home Additions Seattle WA - Unique Home Construction

Q: How much does a home addition cost in Seattle?

Home additions in Seattle start around $375,000 for approximately 500 sq ft at $750 per sq ft, and $575,000+ for 1,000 sq ft or more. Pricing depends on size, foundation, roofline, and finishes. Fixed pricing is provided following a site visit and design consultation.

Q: Do you handle permits and code compliance for home additions?

Yes. Unique Home Construction manages all Seattle permitting, inspections, and code reviews — including structural engineering where needed. The team works directly with the city to avoid delays and keep your project moving.

Renovated Seattle home exterior with a covered front porch, wood accents, dark trim, and refreshed landscaping

Why Build a Home Addition in Seattle?

In Seattle, space is a premium, and so is the opportunity to stay in the neighborhood you love. A well-planned home addition lets you expand your square footage without the cost or disruption of moving. For many homeowners, it’s about accommodating a growing family, planning for aging-in-place, or creating a private workspace that fits today’s routines.

If you’re weighing the cost of moving versus expanding, know this: a thoughtful remodel addition can be a smarter long-term investment, especially with Seattle’s rising home prices and limited lot availability. Our team helps you maximize what you already own.

What Home Additions in Seattle Looks Like

From second stories to kitchen and bathroom expansions, Unique Home Construction focuses on continuity, structure, and how the new space will function day to day. Explore recent home addition projects completed across Seattle to see how we’ve helped clients add space, value, and lasting comfort. View before-and-after transformations, browse finishes and layouts, and get ideas for your own project.

View Portfolio

What Are Types of Seattle Home Additions That Unique Home Construction Builds

As a home addition builder serving Seattle and surrounding neighborhoods, we design and construct additions of all types and sizes. Below are the most common types of additions we deliver.

Bright renovated Seattle interior with a dramatic double-height ceiling, exposed wood beam, glass railing, large windows, and modern pendant lighting.

Second Story Additions Seattle

When there’s no room to build out, build up. Second story additions give you the ability to double your livable square footage without increasing your home’s footprint. We handle the structural analysis, design coordination, and permitting required to make sure your second story addition is both safe and consistent with the rest of your home. This type of expansion is especially valuable in Seattle neighborhoods where lot sizes are tight and property values are climbing.

Get a Free Quote

Renovated Seattle home addition with modern siding, sliding glass doors, exterior stairs, and a raised deck with black metal railings.

Dormer Additions

Dormer additions are a smart way to gain usable space and natural light without a full second-story addition. Unique Home Construction designs both gable and shed dormers, matched to your roof structure and architectural style, with minimal disruption to the rest of your home. For many Seattle homeowners, this is the most efficient way to make an attic livable or carve out space for a bathroom, office, or storage.

Get a Free Quote

Renovated Seattle entryway with warm wood flooring, white walls, a small window, wall hooks, and practical shoe storage.

Mudroom Additions

Adding a mudroom is one of the most functional upgrades you can make. A dedicated entry space gives you room to store coats, shoes, and gear while keeping the rest of your home clean and organized. We help you design a space that fits your home’s layout and your routine, whether it’s a small addition near the garage or a full utility entry off the side of the house. We can also advise on mudroom addition cost, material selection, and weather protection features.

Get a Free Quote

Modern renovated Seattle home exterior with wood siding, large windows, a contemporary garage door, and lush landscaping

Garage Additions Seattle

The area above an attached garage is often underutilized. Building over it allows you to add a bedroom, office, or guest suite. We build attached and detached garages that match the style and structure of your existing home. We design and build both attached and detached garages that match your home’s structure and exterior, reinforcing the framing where needed and aligning the layout to flow with the rest of the house. Whether it’s a one-car garage or a two-story design with finished living space above, we handle zoning, permitting, and structural planning from start to finish.

Get a Free Quote

Modern renovated Seattle kitchen with dramatic black marble surfaces, dark cabinetry, wood accents, a large island, and gold details

Bump Out Additions

Bump-out additions are small expansions with big impact. These additions allow you to push out a wall without the scale or cost of a full addition. In older Seattle homes, we often use bump-outs to create proper primary suites, especially where the second floor doesn’t match the footprint of the first. Most bump-outs are added to the back of the home, since front and side expansions are often limited by Seattle’s setback requirements. If you’re working with a tight lot or want to stay within setback limits, this type of home expansion is often the most effective option.

Get a Free Quote

Renovated Seattle home exterior with white brick, dark siding, a wood front door, updated landscaping, and an attached garage

Kitchen and Bathroom Additions Seattle

Kitchens and bathrooms are two of the most impactful additions you can make. Bathroom additions are common in older Seattle homes that were built with just one bath or without a true primary suite. Kitchen additions allow for larger prep areas, expanded dining space, and modern appliances. From rerouting plumbing to extending foundations, we handle the full scope of work so the new space feels fully integrated

Get a Free Quote

Our home additions design and building skills help homeowners reimagine what’s possible with their existing property.

Ready to turn your home into something truly unique?

Get in touch with us; we are prepared to bring your aspirations of a UNIQUE, lovely, practical, healthy house to reality.

How Much Does a Home Addition in Seattle Cost?

Adding square footage to your Seattle home involves more than just extra walls. Our pricing reflects real completed additions, with costs shaped by the size, foundation, roofline, and the finishes you select.

Addition Size	Starting Range	Includes
Around 500 sq ft	From $750 per sq ft (~$375,000+)	Larger single-room additions or compact two-story builds
Around 1,000 sq ft+	From $575 per sq ft (~$575,000+)	Full-floor expansions, large two-story additions, multi-room layouts

For an accurate proposal, we offer fixed pricing after a site visit and design consultation.

Seattle Home Addition Builder You Can Trust

Planning a home addition takes more than design ideas — it takes coordination, clear communication, and a builder who knows how to manage complexity without losing momentum. Unique Home Construction brings 20+ years of experience building residential additions in Seattle and a proven process that keeps your project on track from first meeting to final walkthrough.

Fixed-Price Estimates – No vague allowances or surprise costs. Our proposals are detailed, transparent, and include all labor and materials — down to the last fixture.
3D Design Consultations – Every project starts with a design plan and a full 3D rendering, so you can visualize how the new space will integrate with your home.
Zoning and Permit Management – We handle all necessary Seattle permits, site reviews, and code compliance — including complex second-story and structural additions.
Daily Site Check-ins – Our project managers visit your site every day to keep progress on track and ensure alignment with the plan.
Remote Monitoring Tools – Traveling or based outside Seattle? We provide regular photo updates and messaging through our secure client portal.
Tech That Simplifies the Process – From scheduling to approvals, we use digital tools to keep things organized and moving — without the back-and-forth delays.
Post-Completion Follow-Ups – After your addition is complete, we walk the space with you, handle final punch-list items, and make sure everything’s right.

Inquire Online

About Us

Hundreds of happy homeowners

Accredited remodeling experts

High-end quality materials

20+ years of
experience

Fully licensed and insured

Top-notch customer
service

Seattle’s Trusted Home Addition Specialists

We’ve completed home additions throughout Seattle — from West Seattle to Green Lake — and our clients consistently say this: “creatively provided options”, “professionalism of the company”, “on time with their projected work timeline”, “communicative throughout the process”. Below are a few highlights, but you can view more reviews or browse our portfolio to see the results for yourself.

See our 5-star reviews on

As featured in:

I hired Unique Construction to complete an interior remodel to a sunroom we turned into an extension off our kitchen. It required work on the exterior siding, interior drywall, wood flooring, cabinetry, ceiling, electrical and duct work. I was impressed with the professionalism of this company. They were on time with their projected work timeline and were very communicative throughout the process. They had skilled workers and Reza, the owner, checked on the project every day. I would highly recommend Unique construction to others and would be happy to use them for a future job.
Amber Malmgren
We chose unique for our master bathroom, living room and outdoor area remodeling,Unique was amazing to deal with. They went above and beyond to finish our beautiful home renovation in time for us to move in. They are professionals in all trades and extremely pleasant to deal with. I highly recommend them as a one-stop shop for all your home renovation requirements.
Cecil Tompkins
This company is amazing! They do high quality work. The workers have lots of experience, are professional and respectful. They make outstanding transformations! I could not believe how beautiful their work was. I appreciated the great communication during the whole project, how they listened to my needs and how they made sure I was completely satisfied. If you are looking to transform your home into something amazing, hire Unique.
Wendy Potter
We had a great experience with UNIQUE Home Construction. We had a full kitchen, bedrooms, bathrooms, fireplace remodel with this great and talented team. They completely changed all of our flooring throughout our whole house. We are extremely happy with the results and all the work that was done. Everything was completed in a timely manner. We cannot tell you enough how outstanding the work they do is. If you want a job well done call UNIQUE Home Construction.
Angels Garden
I started with a different contractor for laminate installation for my second home. Unfortunately, the work was grossly unsatisfactory and I had to let go of that contractor midway. Thereafter, started work with Reza from Unique Home Construction. Since we were at our vacation home only for a few days, we had a set deadline for finishing the work. Reza and his people worked till midnight to get the work done on time. Greatly appreciate the effort he put in! Would definitely recommend.
Tuhin Banerjee
I have worked with Reza on a number of projects and I am so impressed with his business approach, his design style and his quality work. He has transformed several houses, not just with the traditional quality remodel characteristics, but bringing in design elements that wow buyers. Not only does he incorporate cutting edge trends, he is also concerned about quality for those things you don’t see. He is such a pleasure to work with. Entrepreneurial and driven to do extraordinary work with extraordinary results, while being a great down to earth guy at the same time. He is an asset and I trust that he will bring his best to the table in any business endeavor.
Tina Terada

Home Additions FAQs

Curious about pricing, the process, or what it’s like to work with us? Our FAQ covers the questions we hear most — and gives you a better feel for how we do things at Unique Home Construction.

Call Today +1 (206) 717-7314

Home additions in Seattle start around $375,000 for 500 sq ft at $750 per sq ft, and $575,000+ for 1,000 sq ft or more. Pricing depends on size, foundation, roofline, and finishes. Fixed pricing follows a site visit. Related article Home Addition Cost in Seattle 2026

A remodel updates existing space. A home addition expands your home’s footprint — either by building out, up, or over. In Seattle, additions often involve structural, zoning, and permit considerations that go beyond typical interior remodels.

Timelines vary by project size and complexity. Most home additions in Seattle take 3 to 6 months from initial permitting to final walkthrough. Second story builds or major reconfigurations may extend beyond that. You’ll receive a clear schedule before work begins.

Yes. We manage all Seattle permitting, inspections, and code reviews — including structural engineering where needed. Our team works directly with the city to avoid delays and keep your project moving.

Mudroom addition cost varies based on size, access, and finish level, but generally starts around $25,000–$40,000. We design for both function and weather durability — including built-ins, flooring, and energy-efficient entry solutions.

Let’s Build the Right Addition for Your Home

If you’re ready to expand your home in a way that adds long-term value and everyday usability, we’re here to help. At Unique Home Construction, we take the time to plan carefully, build precisely, and deliver unique results. Reach out to schedule a consultation and get a fixed-price proposal for your Seattle home addition. Let’s build a space that you’ve been missing.

Get Started