Home Additions San Jose
Home Additions San Jose -- San Jose, CA
“San Jose's Home Addition & ADU Builders”
Design-build room additions, ADUs, second-story builds, and garage conversions across San Jose, Santa Clara, Sunnyvale, and the entire South Bay. Permits handled start to finish. Free estimates.
10+
Cities Served
Since 2011
South Bay Local
8
Project Types
Our Services
From a single-room addition to a full ADU or second story, we handle design, permitting, and construction across the South Bay.
ADU & Granny Flat Construction
Full design-build accessory dwelling units -- attached, detached, or garage-conversion ADUs, permitted start to finish.
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Room Additions
Ground-level room additions -- extra bedroom, family room, or expanded living space built onto your existing home.
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Second Story Additions
Build up instead of out -- full second-story additions that double your living space on the same footprint.
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Garage Conversions
Turn an underused garage into a permitted living space -- bedroom, office, gym, or full ADU.
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Kitchen Additions & Extensions
Expand or extend your kitchen footprint -- more counter space, an island, or a full open-concept layout.
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Bathroom Additions
Add a new full or half bathroom -- primary suite expansion, additional family bathroom, or powder room.
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In-Law Suite Additions
Attached or detached in-law suites with a private bedroom, bathroom, and living space for extended family.
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Home Office & Bonus Room Additions
Purpose-built home offices, bonus rooms, and flex spaces for remote work, hobbies, or extra living space.
Learn MoreWhy San Jose Households Trust Us
We stand behind our work with industry-leading guarantees.
Licensed & Insured
CSLB licensed general contractor
Since 2011
South Bay's trusted design-build team
Workmanship Guaranteed
1-year workmanship warranty
Design-Build, One Contract
Design, permits, and construction together
Free Estimates
On-site walkthrough, no obligation
Experienced Team
Licensed tradespeople on every crew
How It Works
Getting your furniture cleaned is simple. Here's our easy 3-step process.
Text Us for a Free Estimate
Text us for a free, no-obligation on-site walkthrough. We'll ask about your project and schedule a convenient time.
Design, Permit & Build
We design the addition, submit for San Jose permits, and manage every phase of construction on a scheduled timeline.
Final Inspection & Handoff
We coordinate the final city inspection and walk you through the completed project. Your satisfaction is guaranteed.
Transparent Pricing
No hidden fees, no surprises. Get a clear price before we start. All estimates are free.
Garage Conversion
Fastest way to add livable space
From $60,000
- Full insulation and drywall to code
- Electrical and HVAC extension
- New flooring and finish work
- Full city permit included
- 2-4 month typical timeline
Room Addition
Most popular for South Bay families
From $60,000
- Ground-level bedroom or family room addition
- Structural engineering and permits included
- Matched roofline and exterior finish
- Full interior finish -- flooring, drywall, paint
- 1-year workmanship warranty
ADU / Second Story
Maximum square footage added
From $180,000
- Detached ADU or full second-story build
- Complete architectural design + engineering
- Full permit submission and plan-check coordination
- Priority project management
- 1-year workmanship warranty
Prices vary based on square footage, structural scope, and finish level. Text us for a free, itemized on-site estimate.
Trusted Material Partners
We Build With the Best
Planning Your Project Around San Jose's Building Season
Permitting timelines and weather both affect when to start your addition. Here's how we help you plan the right start date.
Start Your Permit Now
Spring is the best time to submit ADU and addition plans -- San Jose plan-check queues are shorter before the summer construction rush, and you'll be ready to break ground by early summer.
Peak Construction Season
Dry, stable weather makes summer ideal for foundation, framing, and roofing work. Book early -- our summer construction calendar fills up months in advance.
Beat the Winter Rain
Fall is the last window to get exterior framing and roofing weathertight before San Jose's rainy season. We prioritize scheduling exterior-critical phases in this window.
Interior Finish Work
Winter months are ideal for interior-focused projects -- kitchen additions, bathroom additions, and finish carpentry -- while weather-sensitive exterior work slows down.
Why San Jose Chooses Us
Transparent pricing, licensed tradespeople, and a workmanship guarantee on every addition.
Licensed, Bonded & Insured
Fully licensed CSLB general contractor carrying general liability and workers' comp on every job site.
Design-Build, One Contract
Architectural design, engineering, permitting, and construction all under a single contract and point of contact.
Permit-First Process
We handle San Jose permit submission and plan-check corrections so your project stays on schedule, not stuck in city hall.
Local South Bay Team
Based in San Jose and familiar with the zoning, setback, and soil conditions across Santa Clara County.
Frequently Asked Questions
Got questions about home additions or ADUs in San Jose? We've got answers.
Most projects range from $45,000 for a bathroom addition to $450,000+ for a full second-story or large ADU. Garage conversions and bonus rooms fall in the $55,000-$120,000 range. Every project gets a free, itemized on-site estimate before any contract is signed.
Areas We Serve Across the South Bay
We build room additions, ADUs, and second-story builds throughout San Jose and Santa Clara County. Click a city on the map or find your city below.
San Jose
Room additions, ADUs, and full home extensions across all San Jose neighborhoods -- from Willow Glen to Almaden Valley.
Free on-site estimateSanta Clara
Design-build additions for Santa Clara homes near the tech corridor and Santa Clara University.
Free estimates availableSunnyvale
Room additions and ADU builds for Sunnyvale's mix of townhomes and single-family homes.
Licensed and insuredCupertino
Home additions for Cupertino homes, from De Anza-area lots to Monta Vista's larger family properties.
Free on-site quotesLos Gatos
Detail-focused additions for Los Gatos' upscale homes, including custom second-story builds.
Engineering-first designMilpitas
Reliable room additions, ADUs, and garage conversions for Milpitas families near the Great Mall.
Free on-site estimatePlanning a Home Addition or ADU Near You?
We are a local South Bay design-build contractor -- not a national franchise. When you're ready to add a room, an ADU, or a full second story, our team is based in San Jose and available for a free on-site walkthrough.
Get Your Free Estimate Today
Whether you need a new ADU, a room addition, or a full second story, our team is ready to scope your project. Text us now for a free on-site estimate.
Since 2011
South Bay Local
Licensed
Bonded & Insured
10+
Cities Served
Free
Estimates Always