ADU Construction in Belmont, CA

Quartz Construction builds accessory dwelling units (ADUs) in Belmont, CA. Whether you need a detached backyard ADU, a garage conversion, or a junior ADU, our licensed team handles everything — design, permits, and construction. Licensed CSLB #1003436 | BBB A+ | 4.9⭐ (65+ Reviews)

ADU Types We Build in Belmont

• Detached Backyard ADU — Separate, self-contained unit in your backyard. Ideal for rental income or family member housing.
• Attached ADU — Addition to your existing home with separate entrance and utilities.
• Garage Conversion ADU — Transform your Belmont garage into a fully permitted living space at lower cost.
• Junior ADU (JADU) — Smaller unit within your existing home structure, permitting often simpler.
• Above-Garage ADU — Second-story unit built over your existing garage.

ADU Cost in Belmont

ADU construction in Belmont costs $155,000–$360,000 for a detached ADU. Garage conversions are more affordable at $60,000–$120,000. The high cost of housing in Belmont means a well-built ADU typically rents for $2,500–$4,500/month, achieving full ROI in 5–8 years.

ADU Permits in Belmont

California state law (AB 2221, SB 9) allows ADUs on all single-family lots, including in Belmont. Belmont has streamlined its ADU permit process in compliance with state mandates. Quartz Construction handles all permitting, engineering, and inspections — you don’t need to navigate City Hall alone.

ADU Rental Income in Belmont

ADU rental income in Belmont typically ranges $2,200–$4,000/month depending on size and finishes. With Bay Area rents this high, most Belmont homeowners recoup their ADU investment within 6–8 years while simultaneously increasing their property value by $200,000–$400,000+.

Get a Free ADU Estimate in Belmont

Ready to build an ADU in Belmont? Quartz Construction provides free ADU consultations including site assessment, permit feasibility review, and construction estimate. Call (650) 749-7436 or fill out our contact form. CSLB #1003436 | BBB A+ | Serving Belmont and all Bay Area cities.