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Detached Backyard ADU in San Mateo, CA

Private backyard cottages that add space, privacy, and value to your home.

6 - 9 months1-year workmanship warrantyFree Estimates
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Starting at $230,000|Typical range: $230,000 - $400,000
Detached backyard cottage, based on size and site access.

About Our Detached Backyard ADU Service

A detached backyard ADU — sometimes called a granny flat, casita, or cottage — is a standalone home in your backyard with its own entrance, kitchen, bath, and yard access. It offers more privacy than an attached unit and is perfect for rental income, a home office, or housing family. We site the cottage to maximize your remaining yard, protect your privacy and your neighbors', and match your main home's architectural style. From cozy 400 sq ft studios to full one-bedroom cottages, every backyard ADU we build is independently metered and fully permitted.

What's Included

Standalone backyard structure
Own entrance & outdoor space
Matched to your home's style
Independently metered utilities
Optimized yard placement
Studio to one-bedroom layouts

Our Process

1

Yard Planning

We map the ideal footprint and orientation so the cottage preserves usable yard, sunlight, and privacy for everyone.

2

Design & Approval

We design a cottage that complements your main home and secure ministerial ADU approval from the city.

3

Foundation & Build

We pour the foundation, frame the structure, and run separate utilities to the backyard unit.

4

Landscape & Finish

We finish interiors, connect the entrance path, and tidy the surrounding yard for a move-in-ready cottage.

Why Detached Backyard ADU Matters

  • Maximum privacy for tenants or family
  • Strong rental demand on the Peninsula
  • Flexible use: rental, office, or guest house
  • Preserves usable backyard when planned well
  • Independent, self-contained home

Frequently Asked Questions

How close to the property line can a backyard ADU be?
State law requires only a 4-foot side and rear setback for a new detached ADU, letting you tuck a cottage into the corner of your San Mateo lot while preserving usable yard.
Can a backyard cottage have its own address?
Yes. Detached ADUs receive their own unit designation and can have separate utility meters, mailboxes, and lease agreements.
Will a backyard ADU block my neighbor's light?
We design within height limits (typically 16-18 ft for a single story) and orient the unit to minimize shadowing, which also helps approvals go smoothly.

Detached Backyard ADU Service Areas

We provide detached backyard adu across San Mateo and the Peninsula, including:

San MateoBurlingameFoster CitySan CarlosBelmontRedwood CityMillbraeHillsboroughSan BrunoHalf Moon Bay

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Free on-site estimate

Starting at

$230,000

Detached backyard cottage, based on size and site access.

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Duration

6 - 9 months

Warranty

1-year workmanship 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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