Add square footage that fits your plan

Seattle Home Additions: More Room, Smart Budget

Projects from
$200,000
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All fixtures, materials, and labor included.
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Built by a local, vetted contractor.
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6 months average build
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Permit processing, project planning, 3D visual and design plans.

Plan the right space, the smart way

Seattle Home Additions That Fit Your Life

Grow your existing home with a clear plan that balances more space and a realistic budget. We map out room additions, from kitchen bumps and built-ins to a larger living area, extra bedroom, or home theater. Considering aging parents or frequent guests? Explore an in-law suite, ADU, or garage conversion to finished living space. Need major square footage? Compare second story additions versus bump outs.

You’ll see cost drivers (labor, materials, HVAC systems), average cost ranges per square foot, site preparation needs, and how choices affect market value. Our team handles permitting, building codes, and local code compliance across Seattle to keep your project on track.

Bedroom with wooden slat headboard, white bedding, decorative pillows, bedside tables, and a window showing outdoor trees.

Choose the right path to more space

Popular Home Addition Options in Seattle

From single-room bump outs to second story additions, garage conversions, and basement upgrades, we add living space that fits your existing home, budget, and Seattle building codes, without guesswork.

Photo of Bedroom

Single-Room & Bump Outs

Need more room fast? A bump out or single-room addition can add a family room, extra bedroom, walk-in closet, or new bathroom with minimal disruption. Smart square footage, lower labor costs, and strong market value for many homeowners.

Exterior of Two-Story House in a Suburban Neighborhood

Second Story Additions

Build up for major square footage. Full second story additions or partial second floor suites expand living space without losing yard. We handle structural design, HVAC systems, permits, and local code to protect your home’s equity.

Modern Home Office Interior

Garage Conversions

Turn an underused garage into finished living space: a legal in-law suite, home office, or home theater. We address site preparation, insulation, adding flooring, egress, and building codes so the new room is comfortable and compliant.

House interior. Basement room with TV

Basement & Lower-Level Expansions

Unlock existing space. Finish your basement into a family room, guest bedroom, or extra living area. We solve moisture, egress, and HVAC needs, then plan materials and layout to maximize value, comfort, and Seattle code compliance.

Four Steps to a Great Remodel

How Our Matching WorksSimple & Fast

Complete a 60-second form. We verify license, insurance, and track record, then introduce 2–3 contractors matched to your scope, budget, and schedule.

See Full Process
Contemporary galley-style kitchen with two-tone cabinetry
1

Share Your Project

Tell us your scope, timeline, and budget: kitchen remodeling, bathroom remodel, whole house remodeling, painting, flooring, or a full design-build plan. Serving the Seattle metro area from Phinney Ridge to Mercer Island.

2

We Vet & Match You

We verify license, insurance, and local track record. Then we introduce 2–3 qualified general contractors that fit your style, schedule, and price range, clean crews with proven quality work and recent projects.

3

Compare Clear Proposals

Get structured, apples-to-apples bids with scope, materials, timeline, and warranties lined up. Our team acts like friendly project managers—answering questions, flagging gaps, and helping you choose the best value.

4

Choose Your Pro & Kick Off

Book a site visit, confirm details, and set milestones. We stay available through contract and start of construction so your dream home plan stays on track for your whole family.

Quick, credible guidance before you build

FAQs for Home Additions in Seattle

How much does a home addition cost in Seattle?

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Home addition cost in Seattle depends on square footage, scope, and finishes. Single room bump outs are often the most cost effective. Second story additions add more space but require structural work and HVAC updates. Your final price is driven by design, labor costs, materials, permits, and site preparation. We provide a realistic budget range after a quick discovery call and a site review.

Do I need a permit for a home addition or ADU in Seattle?

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Yes. Most room additions, garage conversions, second story additions, and accessory dwelling units require plans, permits, and inspections. Seattle building codes regulate structure, fire safety, energy, and egress. We coordinate drawings, engineering, and permit submittals, then schedule inspections to keep your project compliant and moving.

What is the most cost effective way to add square footage?

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The most cost effective ways often start with finishing existing space or small bump outs. Basement finishes and garage conversions can deliver finished living space with lower structural changes. Building up with a second story adds major square footage but increases structural and HVAC complexity. We compare options side by side so you can choose the best value for your home.

Is it cheaper to build up or build out in Seattle?

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Building out with a bump out can be cheaper when site conditions allow. It usually has simpler structure and shorter timelines. Building up with a second story addition preserves yard space and may return more value in some neighborhoods, but it often costs more due to structural reinforcement and HVAC redesign. We model both to show cost, schedule, and code impacts.

How long does a second story addition take?

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A typical second story addition timeline includes design and permits followed by structure, mechanicals, and finishes. Duration varies by size, engineering needs, and inspections. Weather, material lead times, and change orders can affect schedule. We provide a detailed calendar with milestones for framing, utilities, drywall, and punch list so expectations stay clear.

Can I convert my garage to a legal living space in Seattle?

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Yes, a garage conversion can become finished living space if it meets building codes for insulation, ventilation, egress, energy, and HVAC. Many homeowners create an in law suite, home office, or home theater. We evaluate foundation, moisture control, ceiling height, and parking requirements, then handle plans, permits, and inspections for a compliant and comfortable result.

Which home additions add the most value?

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Primary bedroom suites, new bathrooms, and well designed family room additions often deliver strong market value. Second story additions can significantly increase appraisal by adding bedrooms and living area. Value depends on neighborhood comps, quality of finishes, and how well the addition blends with the main house. We plan layouts and materials to maximize long term value.

Can we live in our home during a home addition?

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Yes, many homeowners stay in place during room additions, bump outs, or garage conversions. Expect noise, dust, and limited access to some living spaces. We set up dust control, safe paths, work hours, and staging to reduce disruption. For second story additions or major structural phases, a short temporary move out may be recommended.

Fast estimates with zero pushy sales

Start Your Home Addition the Smart Way

Share your goals, budget, and timeline. We route your Seattle room addition, second story, or ADU to vetted contractors for quick, comparable proposals. Transparent costs, local code guidance, and clean installs. Call now or book a free estimate.

Your Dream Home Starts with 2–3 Contractor Matches
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