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Accessory Dwelling Units and Home Additions

We design and build custom ADUs and home additions across California with full permitting support and communication.

Get Free Consultation Call now

200+ Projects completed

Licensed & insured

Bay Area Specialists

ADU Construction in Sunnyvale, CA

ADU & Home Addition Services

Detached and attached ADU construction solutions for homeowners.
Garage conversions and junior ADU projects statewide compliance.
Single and two story room expansions with structural integration.

Detached ADU Construction

Backyard cottage builds
Separate foundations installed
Independent utility connections
Private entrance layouts
400–800 sqft units
Rental ready delivery

Attached ADU Development

Shared wall structural integration assessment
Cost effective expansion options plans
Garage to apartment conversions services
Separate entrances and utilities planning
Studio and one bedroom layouts
Two bedroom configurations available designs
Equity building renovation strategy approach

Room addition conversion in the South Bay Area

Junior ADU and Conversions

Interior space conversions projects
Ceiling height compliance checks
Egress and light requirements
Efficiency kitchen installations included
Plumbing electrical upgrades performed
Separate access creation planning
Inspection ready documentation preparation

Custom ADU and home addition project in Santa Clara county, CA

Prefab and Modular ADUs

Factory built ADU units
Accelerated installation timelines onsite
Pre engineered structural systems
Energy efficient materials specified
Minimal site disruption planning
Modern and Mediterranean designs
Turnkey delivery solutions provided

Two-story home expansion in San Jose, CA

Two Story Additions

Second story construction
Foundation capacity analysis
Load bearing modifications
Staircase installation services
Roof structure reconstruction
Master suite expansions

Single-story home addition in Campbell, CA

Single Story Additions

Bedroom addition builds
Bathroom expansion projects
Kitchen extension construction
Family room enlargements
Concrete foundation pouring
Exterior finish integration

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Recent ADU & Home Addition projects

Trusted by Bay Area homeowners

Explore all our Work

Justin was friendly and easy to work with. He kept schedule and delivered a high quality build. He helped to build an ADU and the results were exceeded my expectations. The addition provides extra space and looks wonderful.

Hyun

ADU construction client

verified reviewS

Residential home addition by Alpine Haus Construction in San Jose, CA

Home Addition in San Jose, CA

ADU Construction in Los Gatos, CA

Home Addition in Sunnyvale, CA

ADU Construction in Sunnyvale, CA

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Why Choose Alpine Haus Construction?

Expert Quality & Expertise You Can Trust

5.0

rated from

Licensed Contractor

CA License #1125348

Fully Insured

Customer Protection

BBB A+ Rating

Quality Workmanship

5 Stars Reviews

Industry Expertise

10+

Years of Experience

100%

Customer Satisfaction

200+

Projects Completed

Custom ADU and home addition project in the Bay Area, CA

Site Planning and Development Process

Comprehensive site evaluation and permitting ensure compliant, efficient ADU and addition construction across California.

Site Assessment and Preparation

Soil testing analysis conducted
Drainage and grading review
Utility capacity verification performed
Property boundary surveys completed
Setback and zoning checks
Access and parking planning

Our ADU & Home Addition Process

Alpine Haus Construction follows a six-phase workflow that manages consultation, design, permitting, construction, inspection, and warranty service.

Consultation

Initial consultation with property assessment and preliminary budgeting

Design

Design development with 3D renderings and architectural plans

Permit

Permit acquisition and regulatory approval coordination

Construction

Active construction with daily oversight

Inspection

Final inspection and documented quality checklist

Warranty

Post-completion warranty and follow-up support

Frequently Asked Questions

What you need to know about ADU and Home Addition, if you still want to know more, contact us!

Get in touch

We begin with a consultation, provide a detailed proposal and timeline, secure approvals, complete construction under project management, and finish with a final walkthrough.

We perform daily job-site cleanup and complete a final thorough cleaning before project handoff.

Project timelines range from a few weeks for small remodels to several months for large-scale renovations, depending on scope and permits.

Begin by scheduling a consultation so we can review your goals, inspect the home, discuss scope, and outline the required steps for planning, design, permitting, and construction.

Service Areas

Alpine Haus provides remodeling services across Silicon Valley and the Peninsula.

Accessory Dwelling Units and Home Additions