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Prefab & Modular ADU in San Mateo, CA

Factory-built modular ADUs installed fast, with less on-site disruption.

4 - 7 monthsManufacturer + 1-year install warrantyFree Estimates
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Starting at $180,000|Typical range: $180,000 - $320,000
Modular unit plus site work, foundation, and connections.

About Our Prefab & Modular ADU Service

Prefab and modular ADUs are built in a controlled factory environment and delivered to your San Mateo lot for rapid installation. Because framing happens off-site in parallel with your foundation and site work, prefab units shorten the on-site timeline and reduce weather delays and neighborhood disruption. We handle the site prep, foundation, crane set, and all utility connections, then finish the unit in place. Prefab is ideal for homeowners who want a predictable budget and a modern, energy-efficient backyard home without months of on-site construction.

What's Included

Factory-built modules
Faster on-site timeline
Predictable fixed pricing
Modern, energy-efficient design
Crane set & site connection
Full permit management

Our Process

1

Model & Site Fit

We match a modular floor plan to your lot and confirm crane access and setbacks before ordering.

2

Permits & Foundation

While the unit is fabricated off-site, we permit the project and prepare the foundation and utilities on your lot.

3

Delivery & Set

The module is delivered and craned onto the foundation in a single day, then anchored and weather-sealed.

4

Connect & Finish

We tie in utilities, complete on-site finish work, and pass final inspection for a ready-to-live-in unit.

Why Prefab & Modular ADU Matters

  • Shortest on-site construction window
  • Fewer weather and labor delays
  • Predictable, fixed-cost budgeting
  • Energy-efficient modern finishes
  • Less disruption to your neighborhood

Frequently Asked Questions

Is a prefab ADU lower quality than a site-built one?
No. Factory construction is done in a controlled environment with tight tolerances and inspections, and modular ADUs must meet the same California building and energy codes as site-built homes.
How much faster is prefab?
Because the unit is fabricated while your foundation and utilities are prepared, the on-site phase is much shorter — often weeks instead of months once the module arrives.
Do I still need permits for a prefab ADU?
Yes. Site work, foundation, and utility connections all require permits, which we manage for you along with the state modular approvals.

Prefab & Modular ADU Service Areas

We provide prefab & modular adu across San Mateo and the Peninsula, including:

San MateoBurlingameFoster CitySan CarlosBelmontRedwood CityMillbraeHillsboroughSan BrunoHalf Moon Bay

Get a Free Quote

Free on-site estimate

Starting at

$180,000

Modular unit plus site work, foundation, and connections.

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Duration

4 - 7 months

Warranty

Manufacturer + 1-year install warranty

Other Services

Why Choose Us

  • Licensed & Insured
  • Satisfaction Guaranteed
  • Free Estimates
  • San Mateo Local
  • Design-Permit-Build
  • 1-Year Workmanship Warranty

What Our Customers Say

Get Your Free Estimate Today

Whether you're planning a detached backyard ADU, a garage conversion, or a home addition, our team is ready to help. Text or call us for a free feasibility review.

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Licensed

& Insured

Free

Estimates

10+

Peninsula Cities

Free

Estimates Always

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