ADU Builder in Fremont
Looking for an ADU builder in Fremont? Options range from $175K for a garage conversion to $550K+ for a large detached unit. Custom Home builds detached, attached, and garage conversion ADUs in Fremont with full 3D visualization and itemized pricing through our two-phase process.
How much does an ADU cost in Fremont?
Fremont ADU costs range from $175K-$275K for a garage conversion to $300K-$550K for a detached unit in 2026. Custom Home's two-phase process provides 3D visualization and exact pricing before construction begins.
Why Fremont is a Strong Market for ADU Construction
Fremont is a strong market for ADU construction, with property values and rental demand that support the investment. Homeowners use ADUs for rental income, multigenerational living, and home offices. The East Bay’s combination of value and lifestyle continues to attract quality-minded homeowners.
Custom Home builds ADUs in Fremont with the same two-phase design-build process we use for custom homes. You see the complete design in 3D and receive itemized pricing before any construction begins.
Types of ADUs We Build in Fremont
Detached ADUs
A standalone structure in your backyard, typically 400-1,200 sqft. Detached ADUs offer the most privacy and design flexibility. They work well for rental units, home offices, or multigenerational living. Construction costs in Fremont typically range from $300K to $550K.
Attached ADUs
Built as an addition to your existing home, sharing at least one wall. Attached ADUs are typically more cost-effective than detached units since they share structural elements with the main house. They are a good fit for family members who want proximity while maintaining separate living spaces.
Garage Conversions
Converting an existing garage into a living space is the most affordable ADU option in Fremont, starting from $175K. Since the structure already exists, you save on foundation, framing, and roofing costs.
Fremont ADU Permitting
Fremont’s Community Development Department handles building permits through their online portal. Standard residential plan review takes 4-8 weeks. The city has been proactive about ADU permitting, offering streamlined review for qualifying projects.
Custom Home manages the entire ADU permitting process in Fremont, preparing plans that meet local requirements for efficient review and approval.
ADU Rental Income Potential in Fremont
Fremont’s rental market supports strong returns for ADU owners. Estimated monthly rental rates:
- Studio/1-bedroom (400-600 sqft): $2,400-$2,900/month
- 1-bedroom (600-800 sqft): $2,800-$3,500/month
- 2-bedroom (800-1,200 sqft): $3,300-$3,800/month
At these rates, many ADU investments pay for themselves within 7-12 years through rental income alone, not counting the property value increase that a permitted ADU provides. For a detailed breakdown of what drives costs, read our ADU cost guide for the Bay Area.
Pricing for ADU Construction in Fremont
Fremont ADU construction costs range from $175K for a basic garage conversion to $550K+ for a large detached unit with premium finishes. Per-square-foot costs typically run $350-$525/sqft. Garage conversions are the most cost-effective option since the structure already exists. Custom Home provides itemized pricing during Phase 1 so you know every cost before committing.
Fremont Permit Requirements
Fremont's Community Development Department handles building permits through their online portal. Standard residential plan review takes 4-8 weeks. The city has been proactive about ADU permitting, offering streamlined review for qualifying projects. Custom Home handles the entire ADU permitting process, preparing plans that meet local requirements for efficient approval.
ADU Construction in Fremont: FAQ
What does ADU construction cost in Fremont?
ADU costs in Fremont range from $175K for a garage conversion to $550K+ for a large detached unit. The biggest cost factors are ADU type, size, finishes, and utility connections. Custom Home provides itemized pricing during Phase 1 so you know every cost upfront.
How long does it take to build an ADU in Fremont?
ADU construction in Fremont typically takes 6-12 months from design to move-in. Garage conversions are fastest at 4-6 months, while detached units take 8-12 months including permits. Custom Home's design phase front-loads decisions to keep construction on schedule.
Does Fremont offer pre-approved ADU plans?
Many Bay Area cities, including some in Alameda County, offer pre-approved ADU plans that can reduce permitting time. Custom Home can advise on whether pre-approved plans are available for your Fremont property or whether a custom design is the better option.