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Double-Height ADU

Studio-AMA
1175 SF
(extra-large)
1, 2
1.5
  • Site-built
Two-story ADU with two floor plan options. The design is unique in that you can build one ADU with the option of adding a second one later. The design works either a standalone ADU or as a duplex.

Basic details

Square-Footage

1175 SF

Inside wall to inside wall measurements.

Plan Type

site-built-traditional

Bedrooms

1, 2

bathrooms

1.5
To help abate the state-wide housing crisis, the California state government recently passed legislation to ensure local municipalities adopt policies to permit accessory dwelling units (ADUs) on lots zoned for single-family residential use. This effectively makes R-1 zoning (single-family) into duplex (two-unit) zoning. Some municipalities are even now looking at ways to permit two ADUs on a single-family lot as well as increasing height limits to allow two-story ADUs. The Double-Height ADU concept anticipates these coming changes to single-family residential zoning. The ADU is designed to be flexible and easy to build. Inspired by the aesthetics of a backyard shed, the simple gable form and corrugated metal siding with darkened aluminum details lends the ADU a welcoming yet understated design. An optional 10’-0” deep deck in the front of the ADU provides semi-private outdoor space with enough room for grilling and small dining. The ADU is designed with the latest thinking in energy and water efficiency in mind. For example, fully electric appliances and heating systems mean natural gas is not required, thus preventing methane greenhouse gas emissions. An energy-efficient ductless mini-split heat pump system heats and cools the space while an electric tankless water heater heats the ADU’s hot water supply. Optional solar roof photovoltaics and a home battery storage system can also help reduce reliance on the regional electrical grid. In addition, low-flow plumbing fixtures help minimize water use. The exterior walls and roof assemblies are designed to Passive House standards with a high-performance insulated approach, yielding high R-values and reducing the demand on energy to power the space.

Pre-reviewed jurisdictions

“Pre-reviewed” Plans

These are both site-built and prefabricated plans that have been pre-reviewed for compliance with applicable building code requirements. It is crucial that you begin by first contacting your local jurisdiction to understand what is and is not possible on your site before you proceed with selecting a plan. You should also ask your jurisdiction about their policy for use of pre-reviewed plans, as each individual city and county is unique. 


NOTE: A pre-reviewed plan will require additional information and tailoring before it can be submitted to your jurisdiction for ADU permit approval. See FAQs page for more details.

  • What does "pre-reviewed" mean?

Click each jurisdiction to access their ADU webpage and/or resources.

NOTE: This program is currently in beta launch and we’re working on adding more “pre-reviewed” plans. Check back often for updates!

IMPORTANT: Even “pre-reviewed” plans must be submitted along with additional project-specific information for final review and permit approval by your jurisdiction’s building department.

Features

Click or hover each item for a description. 

All the appliances and HVAC are electric instead of natural gas.

  • All electric

The design and electrical system could easily have a solar system added to the ADU.

  • Solar-ready

A range of strategies to minimize the energy consumption, such as LED lighting, efficient HVAC systems, and well-insulated walls and ceilings.

  • Energy-efficient

A design that provides outdoor amenities such as a patio or deck.

  • Indoor/outdoor living

An ADU with a dedicated space and hookups for a washer and dryer.

  • In-unit washer/dryer

Images

Click the images to open a slideshow.

Gallery Floorplans

Floorplan variations

There are two floor plans options within the same 17’-6” x 38’-0” building footprint: Option A: 1 bed/1.5 bath model (1,000 SF) Option B: 2 bed/1.5 bath model (1,175 SF) Option A has a double-height space in the living room with a bonus ‘office’ mezzanine above. Option B adds a second bedroom in the space above the living room. The idea is that one could easily add two of these ADUs side-by-side to effectively create a backyard duplex.

Cost Information

License fee:

$0

The license fee is what the designer will charge you to use their plan.

Contact the designer to move forward with this plan. 

Estimated construction cost

Exact costs vary based on site conditions, supply costs, labor costs, etc.

$200,000 - $450,000 (depending on which floor plan is selected, level of finish & fixture quality, fluctuations in material & labor pricing)

Professional fee

The rate or cost the designer will charge to complete the plan for your specific parcel and project.

$180 per hour

Other estimated expenses

- Structural Engineering - Title 24 Energy Report - Civil Engineering - Landscape Design - Local Permitting Fees

Additional Information

If the designer supplied any additional information about this design, it is included below.

Double-Height ADU website
The double-height (two-story) accessory dwelling unit is a relatively new concept that responds to California cities and towns relaxing local height limit restrictions. With a compact footprint, this ADU model allows you to preserve more ground area in your backyard while being able to accommodate more square footage than you otherwise would in single-story ADU.

Build this adu

1. Schedule an ADU feasibility consult to get started

Check what types of ADUs you can build on your property and get support with project planning, determining potential costs, and more from the Napa Sonoma ADU Center.
This link takes you to the Napa Sonoma ADU Center website
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2. Contact the designer

To move forward with this plan, contact the designer using the information included at the link below.
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Send an email to yourself (or someone else) with a link to this listing. You can also add notes about the listing. 

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Please read these Terms & Conditions (“Terms”) carefully before contacting the Accessory Dwelling Unit (“ADU”) designer or firm and potentially proceeding with the purchase (licensing) of an ADU plan, as it contains important information regarding limitations of liability.

Your use of the ADU Plan Gallery found at www.plans.napasonomaadu.org (“Gallery Page”) to access designer contact information is conditional upon your acceptance of and compliance with these Terms.

By using the Gallery Page to obtain designer contact information, you agree to be bound by these Terms. If you disagree with any part of these Terms, then you do not have permission to use the Gallery Page to obtain designer contact information.

1 – Approval Authority. Your local jurisdiction’s building department has final review and approval authority for any ADU construction drawings and related permit application materials.

2 – Confirming Site Suitability Prior to Plan Purchase. It is your responsibility to understand what may or may not be allowed on your property by consulting with your local jurisdiction about requirements, regulations and limitations prior to purchasing an ADU plan.

3 – Plan Ownership and Responsibility. Any plans you purchase are the property of the ADU designer or firm that developed them, and use of those plans are subject to any copyrights, conditions, requirements or limitations established by the designer or firm.

4 – Liability from Plan Purchase and Use. Any liability or legal action arising from your engagement with a designer or ADU firm or from the purchase and use of their plan shall be governed by the contract you sign with that designer or firm. Napa Sonoma ADU Center, Napa Valley Community Foundation and Baird+Driskell Community Planning, who developed and manage the Gallery Page, are in no way a party to that contract or in any way, shape or form liable for your use of the plan and resulting ADU.

5 – “Pre-Review” Status. Napa Sonoma ADU Center, Napa Valley Community Foundation, and Baird+Driskell Community Planning, acting as their contractor, engaged a third-party reviewer, BPR Consulting Group, to review some of the plans featured on the Gallery Page for compliance with applicable building codes. The letter reflecting BPR Consulting Group’s review and conclusions is provided on the site as a courtesy and represents BPR Consulting Group’s professional judgment based on the information provided to them by the relevant designer or ADU firm. Napa Sonoma ADU Center, Napa Valley Community Foundation and Baird+Driskell Community Planning do not warrant for the accuracy of the review and are in no way responsible or liable for their work. Further, Napa Sonoma ADU Center, Napa Valley Community Foundation and Baird+Driskell Community Planning do not claim or represent that BPR’s review letter has any authority in the review and approval process with any specific jurisdiction.

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This limitation of liability reflects the allocation of risk between you and us. The limitation specified in this section will survive and apply even if any limited remedy specified in these Terms is found to have failed of its essential purpose. The limitations of liability provided in these Terms inure to the benefit of Napa Sonoma ADU Center, Napa Valley Community Foundation, and Baird+Driskell Community Planning.

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CONTACTING THE DESIGNER

To move forward with this plan, please contact the designer using the information below.

Plan name:

Double-Height ADU

Designer:

Studio-AMA

Email address:

adam@studio-ama.com

Other contact information:

Phone: (415) 972-9086

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