Creating More Space.

ON Design & Remodeling is a family-owned general contractor based in San Jose. We design and build home additions, room expansions, ADUs, and full kitchen remodels.

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400+
Projects Completed
5
Avg Google Rating
15+
Years Serving San Jose
Licensed
& Insured
What We Do

Every trade, one trusted crew.

Front home addition under construction in San Jose
Home Additions
We pour new stem-wall foundations, frame with LVL beams, and match rooflines so the addition looks original. Every structural tie-in is engineer-stamped and city-inspected.
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Framed room addition with window openings
Room Additions
Need a fourth bedroom or bigger living area? We run dedicated HVAC lines, install Milgard low-E windows, and integrate LED recessed lighting seamlessly into existing circuits.
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Completed backyard ADU with modern siding
ADU Construction
From garage conversions to ground-up 499 sq ft backyard cottages, we handle San Jose’s ADU permits in-house. Units include full kitchens, tankless water heaters, and separate meters.
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Modern white kitchen remodel with waterfall island
Kitchen Remodeling
We re-route plumbing for islands, install soft-close cabinets, and lay large-format porcelain slabs without lippage. LED under-cabinet lighting and USB outlets are standard.
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Expanded master bathroom with freestanding tub
Bathroom Expansions
Push out a wall to fit a soaking tub or double vanity. We waterproof with Schluter systems, tile to the ceiling, and install silent Panasonic exhaust fans.
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Architect reviewing blueprints on tablet
Permit & Design Services
Our in-house drafting team creates 3D renderings and submits complete plan sets to the city. You get permit approval faster and construction starts sooner.
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How We Work

Simple process, no surprises.

01
Free Consultation
We come to you, learn your goals, and answer every question. No pressure, no sales pitch.
02
Detailed Quote
A written scope of work with line-item pricing. You know exactly what you are paying for before we start.
03
We Build It
Our own crew on site, daily updates, and a clean worksite every evening. No subcontractor surprises.
04
Final Walkthrough
We walk every room with you before calling it done. You sign off, we consider it a success.
Reviews

What San Jose homeowners say.

"ON added a 400 sq ft master suite that feels like it was always part of the house. Permits were approved in three weeks and the crew cleaned up every day."

David L.
Master Suite Addition

"They turned our detached garage into a rentable ADU. Separate electrical panel, mini-split HVAC, and a full kitchenette—done in six weeks."

Elena R.
Garage-to-ADU Conversion

"The kitchen expansion opened the space to the backyard. New quartz island, subway tile backsplash, and hidden outlets in the breakfast bar—perfect."

James K.
Kitchen Expansion
Get in Touch

Ready to add space?

Call (408) 457-8539 for your free design consultation and quote. We respond within one business day.

(408) 457-8539
San Jose, CA — serving the surrounding area
Mon-Sat, 8am-6pm