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What is an Accessory Dwelling Unit (ADU)?

An ADU is a secondary residential dwelling unit that can be located within or detached from the main residential structure on a single-family residential lot.

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Revolutionize the Single-Family Residence

Simple renovations such as bathroom upgrades or kitchen re-layout are the usual methods implemented to enhance a house value. Nothing wrong with those approaches.  But the absolute best thing, bar-none, for homeowners to do is adding square footage to their homes, legally. 

And as of January 1, 2020, the California state law on Accessory Dwelling Unit (ADU) gave homeowners the chance to do so without interference by the local authority (state law trumps over city/county law). 


A simple summary made by California Association of Realtors (C.A.R.) regarding this new ADU law, can also be found here


In essence, homeowners are legally allowed to create additional space for their home, which will lead to increased intrinsic valuation of the homes.

Aerial View of a Houses

Types of ADU


An extension of the existing home structure, which is attached to the primary dwelling that may include full amenities.


An independent structure entirely separate from the primary dwelling that may include full amenities.

Junior (JADU)

A conversion of an existing garage or space, under 500 sq ft, within the main residential unit that may include full amenities.

How You Can Benefit from an ADU


Permitted Additional Space to Existing House

Opportunities to Generate Extra Income

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Significantly Increase the Intrinsic Value of the Home

We Got You Covered from Start to Finish

Feasibility Study






Design & Build Process


Our company's principal is highly involved from the beginning of the project to the end of it. A site consultation is where our clients meet the principal discussing the clients' needs. We provide honest and straightforward feedback along with professional advice backed by two decades of industry experience. We will make a customized ADU solution based on our clients' needs and budget.


Combining the needs of our clients and their budget, we come up with a custom tailored conceptual floorplan along with preliminary budget. Client will sign a proposal to engage us on the design-build service.


We get down on the nitty gritty of the full design aspect of the ADU. We fine tune the floorplans, create sections, elevations, roof plans, structural plans (if necessary), Title 24 (if necessary). We also offer optional service in creating a site plan if the client does not have one ready. Once the design package is ready, then we submit it to the local planning department for plan review.



This is the moment we all have been waiting. Our plans are approved and we are ready to move forward with constructing the ADU. Both parties will sign a construction working agreement based on the signed proposal.


We are putting all of our resources into making your approved plans into reality. This is where the rubber meets the road. Our team and our sub-contractors are working hand-in-hand to construct the ADU until you are ready to turn the key of the front door!


In-House ADU

Financing Program

At CHISEL & TOOL, we understand that finance is at the forefront of every important decision, especially for a wealth-altering product such as an ADU.  That's why we offer our proprietary financing program to our select homeowners.  We have the ability to plan, design and build your ADU at no upfront cost and no interest to you.  

Program Highlights:

  • No upfront costs

  • 0% Financing

  • 10% of the ADU rental revenue payable to homeowner

  • 10-year lease agreement, with allowable sublease, of the ADU

  • Chisel & Tool appointed as ADU's property manager

  • ADU handover at the end of 10-year period at no cost

  • Early termination allowed by paying the full principal amount at zero interest

NOTE:  Chisel & Tool's In-House Financing Program is subject to Terms and Conditions. 

Need an Estimate?

Summer House

Contact us at 1-877-60-BUILD or email us 

to get started with a no-obligation consultation, comprehensive site visit

and an accurate quote for your customized project.

Upload your architectural plans for

expedited processing and receive constructive advice within 24 hrs.

Frequently Asked Questions | FAQ

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