Room Addition Contractor San Mateo CA | Quartz Construction
Quartz Construction & Remodeling builds room additions in San Mateo, CA including master bedroom suites, family rooms, home offices, sunrooms, and second-story additions. Room additions in San Mateo cost $150–$400 per sq ft depending on type, complexity, and finishes. We handle everything: architectural design, structural engineering, San Mateo building permits, foundation work, framing, all trades, and final finishes. CSLB #1003436 | $2M liability insurance.
Room Addition Types We Build in San Mateo
Industry Resources & Standards:
| Addition Type | Typical Size | Cost Range |
|---|---|---|
| Master Suite Addition | 400–700 sq ft | $80,000–$280,000 |
| Family Room Addition | 300–600 sq ft | $60,000–$200,000 |
| Home Office Addition | 150–300 sq ft | $30,000–$90,000 |
| Sunroom / Bonus Room | 200–400 sq ft | $40,000–$120,000 |
| Second-Story Addition | 400–1,000 sq ft | $100,000–$350,000 |
| In-Law Suite / ADU | 300–600 sq ft | $75,000–$220,000 |
Frequently Asked Questions — Room Additions San Mateo
How long does a room addition take in San Mateo? A room addition in San Mateo takes 5–12 months total: 4–8 weeks for design and engineering, 4–12 weeks for permit approval, and 3–5 months of active construction. Second-story additions take 10–18 months total due to more complex permitting and structural requirements.
Does a room addition require a permit in San Mateo? Yes — all room additions in San Mateo require a building permit. Applications require architectural plans, structural engineering calculations, and energy compliance documents. Quartz Construction prepares and submits all permit documents and handles all city inspections.
How much value does a room addition add in San Mateo? Room additions typically add 60–80% of their cost in immediate market value in San Mateo. Master suite additions and family room additions tend to have the highest ROI in Bay Area markets where additional bedrooms and living space command significant premium pricing.
Free room addition consultation and estimate for San Mateo homeowners. Call (408) 555-1234 or request your free estimate online. CSLB #1003436 | Serving San Mateo and all Bay Area cities.
What Our Clients Say
Join hundreds of happy Bay Area homeowners who trusted Quartz Construction & Remodeling for their projects.
Professional Resources & Regulations
- California Contractors State License Board (CSLB) — Verify contractor licenses
- City of San Jose Building Permits — Permit requirements & inspections
- ENERGY STAR — Energy-efficient materials & standards
Trusted by San Jose Homeowners
4.9/5.0 • 65+ Google Reviews
“Amazing kitchen remodel — on time, on budget. Highly recommend Quartz Construction!”
— Maria S., San Jose
“Professional, communicative, and the bathroom renovation exceeded expectations.”
— David L., Santa Clara
“Built our ADU from scratch — permits, foundation, everything handled seamlessly.”
— Jennifer T., Sunnyvale
Get Your Free Estimate
Licensed • CSLB#1003436 • Serving San Jose & Bay Area
Or call us directly: (650) 749-7436
