ADU Model · 1 Bedroom

499 Sq Ft 1-Bedroom ADU

A true one-bedroom home with French doors to the backyard and 9-foot ceilings. Starting from $235,000.

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A Real One-Bedroom, Under 500 Sq Ft

The 499 is our strongest rental performer. It has what the studio doesn't — a separate bedroom with a door — which is the single biggest jump in what a unit rents for. And by staying just under 500 sq ft, it lands in the simplest permitting tier while remaining well clear of the 750 sq ft impact fee threshold. Like every model in our Bay Area ADU lineup, it's built on your lot as a true design-build project — custom, not prefab.

Model Specifications
Size
499 sq ft
Configuration
1 Bed · 1 Bath
Ceiling Height
9 feet
Starting From
$235,000
Construction
4–5 months
Permit Approval
40–60 days
What's In It
Separate bedroom with door · full kitchen · full bathroom (your choice of tub or walk-in shower) · open living and dining area · French doors to the backyard · in-unit washer/dryer hookup · 9-foot ceilings throughout · private entrance · available in Modern or Farmhouse
Impact Fees
Exempt — well under California's 750 sq ft threshold. Saves $10,000–$30,000 compared to a larger unit.

Floor Plan & Interior

A proper one-bedroom layout in a compact footprint. The bedroom is fully separated by a door — not a nook or an alcove — with the kitchen, living, and dining sharing one bright open volume under 9-foot ceilings. French doors open the living space directly onto the backyard, which makes the whole unit live considerably larger than its square footage.

499 sq ft 1-bedroom ADU floor plan by California Bay Builders Bay Area 499 sq ft 1-bedroom ADU interior with 9 foot ceilings and open living area by California Bay Builders

Adjustable Within Reason

Door and window placement, bath configuration (your choice of tub or walk-in shower), and every finish selection are yours to make. We'll also adapt the plan to your lot, setbacks, and access.

The value of building from our models is that the layout, engineering, and Title 24 are already dialed in — which is exactly what keeps your price and timeline predictable. Fully custom redesigns are a different scope, and we'll walk you through that during your consultation.

Choose Your Style — Modern or Farmhouse

Same floor plan inside, two completely different looks outside. Your ADU should feel like it belongs on your property — which style fits best depends on your existing home and your city's design guidelines. We'll help you decide during design.

499 sq ft 1-bedroom ADU modern exterior elevation by California Bay Builders Bay Area

Modern

Clean lines, dark window frames, and a low-profile roof. Pairs naturally with contemporary homes and newer Bay Area neighborhoods.

499 sq ft 1-bedroom ADU farmhouse exterior elevation by California Bay Builders Bay Area

Farmhouse

Board-and-batten siding, a pitched roof, and warmer detailing. A natural fit alongside traditional and craftsman-style homes.

Who Builds the 499

This is the model for homeowners who want maximum return per dollar built. A separate bedroom moves a unit into a different rental bracket entirely, and the 499 gets you there for meaningfully less than a two-bedroom.

Serious Rental Income

A door on the bedroom changes who your tenant pool is — couples and professionals rather than students. Our strongest performer on return relative to build cost.

Simpler Permitting

Staying just under 500 sq ft keeps the project in a lighter review tier in many Bay Area jurisdictions. Less friction, fewer surprises.

Long-Term Family Living

A parent or adult child gets a real bedroom and a real front door. Comfortable indefinitely, not just for a season.

Modest Lots

Still compact enough for tighter yards where a 650 or 800 won't clear setbacks and coverage limits.

Why 9-Foot Ceilings Matter

Most builders frame ADUs at 8 feet. Every one of our models is 9 feet — which allows taller windows, more daylight, and a unit that reads as a home rather than a converted space. In a compact plan, ceiling height does more for how a room feels than square footage does.

Gallery

499 sq ft ADU modern front elevation by California Bay Builders 499 sq ft ADU backyard elevation with French doors by California Bay Builders 499 sq ft ADU farmhouse front elevation by California Bay Builders 499 sq ft ADU interior with open living area by California Bay Builders 499 sq ft 1-bedroom ADU floor plan by California Bay Builders

Is the 499 Right for Your Lot?

We'll walk your property, check your setbacks, and tell you honestly what fits — this model or another. Free consultation, no obligation. See pricing, what's included, permits, and financing on our Bay Area ADU page.