Primary Suite Addition
Primary Suite Expansion
Bedroom, spa bath & walk-in closet
Added a full primary suite — bedroom, spa bath, and walk-in closet — built off the existing footprint with a matched roofline and new private entry.
Additions & Extensions
ADDITIONS & EXTENSIONSExpand your home without starting over.
Whether you need more living space, a larger primary suite, an expanded kitchen, a second story, or a connected addition, J&C Contractors helps homeowners plan and build additions that feel like they were always part of the home.
- Licensed & Insured
- 5-Year Workmanship Warranty
- Permit Guidance
- Quality Craftsmanship
Why Homeowners Add On
Need more space? Here’s how we help.
Most additions don’t start with a blueprint — they start with a frustration. A bedroom that’s too small. A kitchen that can’t hold the family. A primary suite that doesn’t exist. Tap any problem below to see how we approach it.
How J&C Helps
We plan and build additional living square footage that gives every member of the household room to breathe — bedrooms, baths, family rooms, and storage designed around how you actually live.
How J&C Helps
We expand and rework the existing home so the floor plan fits the way you live now — without giving up the school district, the neighborhood, or the view you bought into.
How J&C Helps
We extend key gathering spaces to open up sightlines, fold in dining, and create the kind of natural flow that makes daily life and entertaining easier.
How J&C Helps
We design larger bedroom, bath, and closet additions — full primary suites built around privacy, light, and a calm separation from the rest of the home.
How J&C Helps
We build additions, ADUs, garage conversions, and flexible bonus spaces that support how your household actually uses the home today — and adapt as it changes.
Exterior Tie-Ins
Additions that disappear into the original home.
Matched siding, paint, and rooflines on real J&C addition and expansion projects across the Eastside.
Redmond, WA·Two-story addition
What We Build
Types of additions & extensions.
From a single bedroom bump-out to a full second-story addition or detached ADU — every project is engineered, permitted, and built by one accountable general contractor. Tap any card for what’s included.
What’s Included
- Foundation, framing & roof tie-in
- Matching siding & trim profiles
- Electrical, plumbing & HVAC extension
- Interior finishes coordinated with existing home
What’s Included
- King-sized bedrooms with private entry
- Spa-quality bath with walk-in shower
- Custom walk-in closet & dressing area
- Acoustic separation from the rest of the home
What’s Included
- Rear wall bump-out & wider footprint
- New island, pantry, or breakfast nook
- Larger window or door package
- Coordinated flooring & ceiling line
What’s Included
- Vaulted ceilings & exposed beams
- Fireplace relocation or rebuild
- Larger window walls & sliders
- Built-ins, millwork & media walls
What’s Included
- Structural engineering & shoring plan
- Foundation & lateral upgrades
- New roofline with matched pitch
- New stair & second-floor mechanical runs
What’s Included
- Insulation, drywall & HVAC upgrade
- Egress windows & code compliance
- Plumbing & wet-room rough-in
- Finished flooring, lighting & doors
What’s Included
- Zoning & permit feasibility review
- Independent kitchen, bath & entry
- Separate metering where required
- Full landscaping & site tie-in
What’s Included
- Engineered glass & window walls
- Hydronic or radiant floor heat
- Operable skylights & ventilation
- Matched roofline & exterior details
What’s Included
- Covered & cantilevered decks
- Outdoor kitchens & fireplaces
- Composite, hardwood & stone surfaces
- Lighting, audio & weather protection
Interior Expansion
Bigger, better rooms — without losing what your home already does well.
The best additions don’t look like additions. We carry ceiling heights, trim profiles, floor stain, and millwork details from the original home into the new space so the build reads as one continuous interior — not a tacked-on box.
- Vaulted ceilings & exposed beams
- Matched trim & door hardware
- Wider sightlines & flow
- Larger windows & sliders
- Engineered structural openings
- New mechanical & lighting plan
ADUs, Basements & Conversions
More livable square footage — without breaking ground.
Finished basements, garage conversions, and accessory dwelling units pulled from recent J&C projects.
Finished basementSammamish, WA
Pre-build basement
Home office additionBellevue, WA
Covered deck extension
Plan With Us
What to think through before building an addition.
A short homeowner checklist we walk through during every feasibility consultation — so the conversation starts in the right place and nothing gets surprised in framing.
How much space do you actually need?
We help right-size the addition so you're not paying for square footage you won't use — or boxing yourself into a footprint that won't fit how the family grows.
How will the addition connect to the existing home?
Where the doorway, the stair, and the new wall meet the original house drives the entire design. We plan tie-ins first, then finishes.
Will the project require permits?
Most additions trigger structural, mechanical, and energy permits. We pull every one — and manage revisions, inspections, and final sign-off.
Will the roofline, siding, or exterior need to match?
Yes — and matching takes more than ordering the same siding profile. We document paint, fascia, trim depth, and roof pitch before design starts.
How will plumbing, electrical, and HVAC be affected?
Larger additions usually mean a panel upgrade, expanded HVAC capacity, and new plumbing runs. We size systems for the new total, not just the addition.
What finishes should match the existing home?
Floors, trim profiles, door hardware, and paint should read as one home. We carry a finish schedule from the original house into the new space.
How will the addition improve daily living?
Every addition starts with a daily-life conversation: mornings, school nights, weekends, guests. The plan should solve the friction you actually feel.
The J&C Addition Process
A clear path from sketch to final walkthrough.
Consultation & Space Goals
On-site visit to walk the home, listen to the daily friction, and sketch the rough footprint of what an addition could look like.
Site Review & Feasibility
Lot lines, setbacks, easements, zoning, HOA covenants, and structural feasibility — checked before any design dollars are spent.
Planning, Blueprints & Permits
Architectural drawings, structural engineering, energy calcs, and full permit submittal through Seattle, Bellevue, Kirkland, Redmond, or your jurisdiction.
Construction & Integration
Foundation, framing, dry-in, mechanicals, then the careful seam work where the addition meets the original home. Weekly walkthroughs the whole way.
Final Walkthrough & Warranty
Punch list closed, finishes documented, jurisdiction final inspection, and a written 5-Year Workmanship Warranty handed over at the door.
Built To Match Your Home
Additions shouldn’t feel “tacked on.”
A good addition is invisible from the curb and continuous from the inside. We treat the seam — exterior and interior — as the actual deliverable. Below is the short list of details that decide whether an addition looks like one.
Exterior Materials
Siding profile, paint match, soffit depth, and trim millwork — sourced or milled to match the original house.
Roofline Integration
Matched pitch, ridge alignment, and step-flashed tie-ins so the new roof reads as part of the original structure.
Interior Flow
Doorway widths, ceiling heights, and floor transitions planned so the addition feels like one continuous home.
Lighting & Window Placement
Sightlines from existing rooms, daylight angles, and window mullion patterns matched to the original elevation.
Finish Consistency
Floor stain, baseboard profile, door style, and hardware finish carried from the existing home into the new space.
Structural Planning
New foundation pinned and doweled into existing footings, with engineered tie-ins for lateral and gravity loads.
Featured Addition Projects
Real expansions. Real homes.
Rear Bump-Out
Kitchen & Living Room Extension
Kitchen extension, vaulted great room
Rear bump-out extended the kitchen and great room, opened sightlines through to the yard, and added a vaulted ceiling with reclaimed beams.
Garage Conversion / ADU
Garage Conversion to ADU
1-bed ADU with kitchen & bath
Converted a detached garage into a permitted ADU — full kitchen, bath, and laundry — with separate entry, metering, and landscaping.
Second Story Addition
Whole-Home Expansion
Second story, primary suite, new stair
Full second-story pop-top added three bedrooms, a primary suite, and a new stair — with foundation and lateral upgrades to carry the new load.
Why J&C For Additions
Built for larger projects.
Additions, extensions, and second-story builds aren’t remodels with extra square footage — they’re structural projects. J&C is built around them.
General Contracting Experience
Hundreds of completed Seattle-area projects — including additions, ADUs, and major structural builds — under one licensed GC.
Blueprint & Permit Guidance
We coordinate architects, engineers, and the permit office so you're not left chasing revisions and inspections.
Structural Planning
Foundation tie-ins, lateral upgrades, and load calcs engineered for additions, not patched in later.
Communication Throughout The Build
One project manager, weekly walkthroughs, line-item proposals, and no surprise change orders.
5-Year Workmanship Warranty
Every addition is backed by a written 5-Year Workmanship Warranty plus manufacturer warranties on installed product.
Craftsmanship That Blends Old & New
Trim profiles, paint, hardware, and roof details matched so the addition reads as part of the original home.
Primary Suites & Outdoor Living
The rooms most homeowners add — and the ones we love building.
Spa primary bath
New primary bedroomBellevue, WA
Backyard living additionMercer Island, WA
Service Area
Building additions across the King and Snohomish counties.
J&C Contractors plans and builds home additions throughout Seattle, Bellevue, Kirkland, Redmond, Mercer Island, Medina, Clyde Hill, and Yarrow Point — and regularly works in Bothell, Lynnwood, Mill Creek, Snohomish, Woodway, Camano Island, and Clinton. Our crews know the local permit offices, inspectors, and the regional architecture, so the addition lands the first time.
- Bellevue
- Mercer Island
- Medina
- Clyde Hill
- Yarrow Point
- Kirkland
- Redmond
- Seattle
- Newcastle
- Bothell
- Shoreline
- Lynnwood
- Mill Creek
- Snohomish
- Woodway
- Camano Island
- Clinton
- King and Snohomish counties
Additions & Extensions FAQ
Home additions, answered.
Free EstimateTell us what you'd like to add.
A few details and J&C will follow up to schedule a feasibility walkthrough — usually within one business day.
- Licensed & Insured
- 5-Year Workmanship Warranty
- Quality Craftsmanship
- Locally Trusted
Prefer to call? (425) 407-3652
Let’s Expand
READY TO EXPAND
YOUR HOME?
Tell us what kind of space you need, and J&C Contractors will help you plan an addition or extension built around your home, your goals, and your lifestyle.