Quick Answer: A master bedroom addition in San Jose costs $200-$350 per sq ft of new space added, or $80,000-$175,000 for a 300-500 sq ft master bedroom without a bathroom. A full master suite addition (bedroom + en-suite bathroom + walk-in closet) runs $140,000-$280,000+ for a 400-600 sq ft addition. Second-story master bedroom additions cost 15-25% more than first-floor additions due to structural and framing complexity. The cost breakdown: permits ($5,000-$15,000), foundation/framing ($60-$120/sq ft), MEP rough-in ($25-$50/sq ft), insulation + drywall ($20-$35/sq ft), flooring ($15-$40/sq ft), bathroom finishes if included ($20,000-$60,000), and paint/trim ($10-$20/sq ft).
Master Bedroom Addition Cost Guide — San Jose 2025
| Addition Type | Size | Cost Range |
|---|---|---|
| Bedroom only (no bathroom) | 200–300 sq ft | $60,000 – $110,000 |
| Master bedroom + en-suite bath (basic) | 300–400 sq ft | $110,000 – $180,000 |
| Master suite (bedroom + full bath + walk-in closet) | 400–600 sq ft | $150,000 – $260,000 |
| Luxury master suite (spa bath + closet system) | 600–900 sq ft | $250,000 – $450,000 |
| Second-story master suite (full story) | 600–1,000 sq ft | $300,000 – $600,000+ |
What Drives Cost on a Master Bedroom Addition in San Jose
- First floor vs. second story: First-floor additions require a new foundation and slab (or crawl space framing) — expensive but structurally straightforward. Second-story additions require engineering the existing first-floor walls and foundation to support the new load — typically adds $30,000-$60,000 to the project
- En-suite bathroom: Adding a full bathroom to a master bedroom addition costs $30,000-$80,000 depending on size and finishes. The bathroom is typically 20-30% of the total master suite addition budget
- Walk-in closet system: A built-in closet system (California Closets or similar) runs $5,000-$20,000 for a 100-150 sq ft walk-in closet. A basic rod-and-shelf system is $1,500-$5,000
- Connecting corridor: The new master bedroom must connect to the existing home — opening a window into a door, creating a hallway, or relocating a staircase. This connection cost ranges from $3,000 (simple window-to-door conversion) to $30,000+ (rerouting hallway, staircase modification)
Quartz Construction builds master bedroom and master suite additions throughout San Jose. Learn about room additions. CSLB #1003436 | Call (650) 749-7436.
Watch: San Jose Remodeling Projects by Quartz Construction
Watch: Bay Area Remodeling Insights
Expert tips and real project walkthroughs to help you plan your Bay Area home improvement.
What Our Bay Area Clients Say
4.9 ★ average rating across Google, Yelp, and Houzz from 150+ Bay Area homeowners.
"Quartz Construction did an amazing job on our kitchen remodel. The team was professional, on time, and the results exceeded our expectations. Highly recommend to any Bay Area homeowner!"
— Michael T. |
"We hired them for a bathroom remodel in our San Jose home. From permitting to final walkthrough, everything was handled perfectly. The tile work is stunning. 5 stars without hesitation."
— Sarah L. |
"Just finished our ADU garage conversion. The project came in on budget and on schedule — rare in the Bay Area! The rental income already started. Could not be happier with Quartz Construction."
— David R. |
Follow Us
See our latest projects, client photos, and Bay Area remodeling tips:
Get a Free Estimate
Licensed Bay Area contractor — CSLB #1003436 — serving San Jose, Fremont, Oakland, Santa Clara, Sunnyvale and all Bay Area communities.
Call: (650) 749-7436
Related Articles
Get a Free Estimate from Quartz Construction
Licensed General Contractor • CSLB Lic#1003436 • Serving San Jose, Santa Clara & Bay Area
