Home Additions in San Mateo, CA
Room additions and second-story expansions that grow your existing home.
About Our Home Additions Service
When you love your San Mateo home but need more room, a home addition adds square footage without moving. We build attached additions — extra bedrooms, expanded kitchens, family rooms, and full second-story additions — that blend seamlessly with your existing architecture. As a licensed general contractor we manage structural engineering, foundation extensions, roof tie-ins, and interior finishes. Additions are a natural fit for our ADU expertise: we can also build an attached ADU that shares a wall with your home while keeping its own entrance and kitchen.
What's Included
Our Process
Design Consult
We discuss how you use your home and design an addition that adds the space you need while matching your existing style.
Engineering & Permits
We complete structural engineering and secure building permits for the expanded footprint.
Construction
We extend the foundation, frame the addition, tie into the existing roof and systems, and weatherproof the shell.
Finish
Interior finishes are matched to your home, and we pass final inspection for a seamless expansion.
Why Home Additions Matters
- More space without moving
- Adds resale value to your home
- Seamless match to existing architecture
- Option to add an attached ADU
- One licensed contractor, start to finish
Frequently Asked Questions
Do additions require the same permits as an ADU?
Can you match my home's existing style?
Should I build an addition or an ADU?
Home Additions Service Areas
We provide home additions across San Mateo and the Peninsula, including:
Get a Free Quote
Free on-site estimate
Starting at
$90,000
Based on addition size, second-story work, and finishes.
Duration
4 - 9 months
Warranty
1-year workmanship warranty
Other Services
Why Choose Us
- Licensed & Insured
- Satisfaction Guaranteed
- Free Estimates
- San Mateo Local
- Design-Permit-Build
- 1-Year Workmanship Warranty