Home Additions in Seattle
Home Additions in Seattle, WA
Home Additions in Seattle. Local pricing, permits through SDCI, and an honest number on paper before demo.
The promise
A Seattle home addition, engineered, matched, and priced before demo
We check what your Seattle lot and house can carry first, then design and build an addition that looks like it was always there, with one licensed team.
Why choose us
Why choose us for your Seattle home addition
01
We check what your lot and house can carry
Setbacks and coverage decide how much you can add; the existing foundation and framing decide whether you can build up. We check both before you spend on design.
02
An honest number, before demo
Additions hide their cost in the foundation and the tie-in. We itemize the whole scope and lock the number before we start.
03
It looks like it was always there
We match the roofline, siding, windows, and proportions so the addition reads as part of the house, not a box bolted onto the side.
04
We handle the Seattle permit
Additions need a permit, structural engineering, and several inspections through the Seattle Department of Construction and Inspections. We prepare the submittal, pull the permit, and manage the inspections.
Cost
What a home addition costs in Seattle
Home Additions costs depend on the level and your finishes. Here are the levels and local ranges, with your real number set against your actual project.
Level 01
Bump-out or room addition
Extending the footprint on the ground floor.
- New foundation
- Single-story tie-in
- Matched roof and siding
Typical Seattle range: TKTK local range
Level 02
Sunroom or enclosed porch
Adding light-filled or three-season space.
- Foundation or slab
- Generous glazing
- Roof and wall tie-in
Typical Seattle range: TKTK local range
Level 03
Second-story addition
Building up instead of out.
- Foundation and framing reinforcement
- A whole new floor
- Roof rebuilt
Typical Seattle range: TKTK local range
Ranges are placeholders until local pricing is confirmed. See our home addition guide for what drives the cost.
Permits
Home addition permits in Seattle
Most home addition projects in Seattle that go beyond cosmetic need a permit. Here is how it works and how we handle it.
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When a Seattle home addition needs a permit
Additions need a permit, structural engineering, and several inspections. A cosmetic scope often does not. We tell you which you are up front.
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Through SDCI
Home Additions permits run through the Seattle Department of Construction and Inspections. We prepare the submittal and manage plan review and inspections. TKTK confirm current process and portal.
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Permit timelines in Seattle
Review times vary with scope and the city queue. We build the permit window into your schedule and flag it early. TKTK typical review windows.
Local homes
What Seattle homes mean for your home addition
Home Additions projects come with Seattle quirks. These are the local realities we plan around.
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What your Seattle lot allows
Setbacks and lot coverage cap how much you can add. We confirm what your lot allows before anyone draws a plan.
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Tying into an older home
older Craftsman bungalows and pre-war homes bring older foundations and framing that have to be checked before tying in a new addition, especially a second story. We assess before pricing.
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A watertight tie-in
Where new construction meets the old house is where water gets in. We detail the tie-in to stay watertight.
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Structural and seismic
Additions here need engineered load paths and seismic detailing. We build from stamped plans, not assumptions.
FAQ
Seattle home addition FAQs
Can I add on to my Seattle house?
Usually, within limits. Setbacks and coverage cap how much you can add, and your foundation and framing decide whether you can build up. We check both before you spend on design.
Is it cheaper to build up or out?
It depends on your house and lot. Building out needs new foundation; building up may need to reinforce the existing structure but does not use more yard. We price both against your actual home.
Do additions need a permit in Seattle?
Yes, and usually structural engineering and several inspections, through the Seattle Department of Construction and Inspections. We pull the permit and manage the process.
Will the addition match my house?
That is the goal. We match roofline, siding, windows, and proportions so it reads as part of the home. Where an exact match is impossible, we design a deliberate transition.
Can I live in my home during an addition?
Often yes, since the existing house usually stays intact until the tie-in, though a second story is more disruptive. We plan the phasing with you up front.
What Seattle neighborhoods do you work in?
All of them, from Ballard and Fremont to Wallingford and beyond. TKTK confirm the full service area.
Ready when you are
Get a free Seattle home addition estimate
Tell us about your Seattle project and we will call within one business day, walk the space, and put a written estimate together with no pressure to sign.