Room Addition Cost in San Bernardino County (2026): City-by-City Breakdown
A room addition in San Bernardino County costs $255–$510 per sq ft, with a typical mid-size room addition running $94k–$187k at the county average. Small projects start around $43k; large or high-end work can reach $340k or more.
San Bernardino County runs about 15% below the LA County baseline due to Inland Empire labor rates and shorter permit queues that run well below the coastal SoCal average.
Room Addition Cost by Size — SB County Average
County-average ranges (0.85× LA County baseline). Individual cities vary — see the table below.
| Size | Type | Range | Low | High |
|---|---|---|---|---|
| Small | Bump-out / single room | 150–250 sq ft | $43k | $94k |
| Medium | Suite addition | 300–500 sq ft | $94k | $187k |
| Large | Second story / multi-room | 600+ sq ft | $170k | $340k |
Room Addition Cost by City in San Bernardino County
Every city in San Bernardino County, sorted alphabetically. Totals reflect each city's local cost multiplier. Cities in color have full project-specific pages.
| City | Small | Medium | Large |
|---|---|---|---|
| Chino | $44k–$97k | $97k–$194k | $176k–$352k |
| Chino Hills | $48k–$105k | $105k–$209k | $190k–$380k |
| Colton | $41k–$90k | $90k–$181k | $164k–$328k |
| Fontana | $42k–$92k | $92k–$183k | $166k–$332k |
| Hesperia | $39k–$86k | $86k–$172k | $156k–$312k |
| Highland | $42k–$92k | $92k–$183k | $166k–$332k |
| Ontario | $43k–$94k | $94k–$187k | $170k–$340k |
| Rancho Cucamonga | $45k–$99k | $99k–$198k | $180k–$360k |
| Redlands | $44k–$97k | $97k–$194k | $176k–$352k |
| Rialto | $41k–$90k | $90k–$181k | $164k–$328k |
| San Bernardino | $42k–$92k | $92k–$183k | $166k–$332k |
| Upland | $45k–$99k | $99k–$198k | $180k–$360k |
| Victorville | $39k–$86k | $86k–$172k | $156k–$312k |
| Yucaipa | $43k–$94k | $94k–$187k | $170k–$340k |
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Get MatchedWhat Affects Room Addition Cost in San Bernardino County?
- Foundation type.
- Roofline integration.
- MEP (mechanical/electrical/plumbing) extension.
- Permits.
- Soil condition.
- SB County market dynamics: Inland Empire labor rates and shorter permit queues that run well below the coastal SoCal average, which shifts room addition totals about 15% below the LA County baseline.
- City variation within SB County: coastal and hillside cities can run 15–30% above the county mid-point, while inland labor markets price 10–20% below.
Room Addition Sub-Type Comparisons
Bedroom Addition vs Master Suite Addition
A standard bedroom addition is the lowest scope; a master suite (bedroom + bath + walk-in closet) roughly doubles the plumbing scope and total.
Second Story Addition vs Sunroom Addition
Second-story additions require foundation reinforcement and full re-roof; sunrooms (prefab or stick-built) skip much of the structural work.
How to Get the Best Price on a Room Addition in San Bernardino County
- Get 3 line-itemized bids on the same scope through Keystone Connect — SB County room addition pricing varies 10–25% between contractors.
- Compare bids from contractors based in multiple SB County cities; inland-based crews servicing coastal jobs often beat coastal-based pricing.
- Bid in shoulder seasons (Jan–Mar or Sep–Oct) when SB County contractor schedules are open and rush premiums disappear.
- Verify CSLB license, insurance, and bond before paying any deposit. California caps deposits at $1,000 or 10% of contract, whichever is less.
Frequently Asked Questions — Room Addition in San Bernardino County
Keep exploring
Compare room addition costs across San Bernardino County, or browse other projects and guides.
More SB County cost guides
Room Addition by city
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