ADU Expert Explains How to Build Your First ADU (Accessory Dwelling Unit)

Are you a homeowner of a multifamily property looking to add more living space, generate rental income, or increase property value? If so, building an ADU (Accessory Dwelling Unit) may be a viable option for you. We believe that ADUs offer a practical and affordable solution to California’s housing crisis, providing homeowners with additional living space and generating rental income while addressing the state’s shortage of affordable housing.

What is an ADU?

An ADU is a secondary dwelling unit on a property separate from the main house. ADUs can be standalone structures or attached to the main house, ranging in size from a studio to a multi-bedroom unit. ADUs can serve various purposes, such as providing additional living space for family members or renters, creating a home office or studio, or aging in place.

ADU Options

Homeowners can choose from several different types of ADUs, depending on their needs, budget, and local zoning regulations.

Here are a few of the most common types:

Attached ADUs – Attached ADUs are connected to the main house and share at least one wall. They can be built as an addition to the main house or as a conversion of an existing space, such as a garage or basement.

Detached ADUs – Detached ADUs are standalone structures not connected to the main house. They can be built in the backyard or a separate area of the property.

Garage conversions – Garage conversions involve converting an existing garage into an ADU. This is a popular option for homeowners who do not use their garage for parking and want to maximize their living space.

Basement conversions – Similar to garage conversions, basement conversions involve converting an existing basement into an ADU. This option is popular for homeowners who want to add living space without building an addition or detached structure.

Junior ADUs – Junior ADUs are smaller units, typically 500 square feet or less, and have their own entrance, bathroom, and kitchenette. They can be attached or detached and are often used for family members or as rental units.

Rooftop ADUs – Rooftop ADUs involve building an additional story on top of an existing structure, such as a garage or a single-story home. This option is popular in areas with limited space for detached structures.

Modular ADUs – Modular ADUs are prefabricated units built off-site and then transported to the property for installation. This option can be faster and more cost effective than traditional construction methods.

The availability of these different types of ADUs may vary depending on local zoning regulations and building codes. Therefore, homeowners should consult an ADU expert and their local planning department to determine which ADUs are allowed in their area.

Planning and Designing Your ADU

Planning and designing your unit is the first step in building your ADU. This involves determining your budget, deciding on the size and style of your unit, and working with an architect to create a design that meets your needs and complies with local building codes and zoning regulations.

Budgeting and Financing Your ADU

Building an ADU can be expensive, and homeowners may need a loan to finance the project. Understanding the costs involved, including construction, permitting, and design fees, is essential. Homeowners can explore various financing options, such as home equity loans, construction loans, or financing through a lender specializing in ADUs.

Working with Professionals

Building an ADU is a complex process that requires the expertise of architects, contractors, and engineers. Therefore, working with experienced professionals who can guide you through the process and ensure that your ADU is built to code and meets your needs is essential.


Once your plans and financing are secured, it’s time to start construction. This involves obtaining the necessary permits, preparing the site, and working with your contractor to oversee the construction process. It’s essential to stay involved and communicate regularly with your contractor to ensure the project stays on schedule and within budget.

Pros and Cons of ADUs

Like any home improvement project, building an ADU has pros and cons. Here are a few to consider:


  1. Additional living space
  2. Rental income
  3. Increased property value
  4. Flexible use
  5. Affordable housing
  6. Aging in place


  1. High upfront costs
  2. Zoning and building code restrictions
  3. Property taxes
  4. Maintenance and upkeep
  5. Privacy concerns
  6. Neighborhood opposition


Building an ADU can be a great way to add more living space to your property, generate rental income, and increase property value. However, it’s essential to carefully plan and budget for your ADU and work with experienced professionals to ensure a successful project. Building an ADU can be a rewarding and beneficial investment for homeowners with the right approach.

About Joseph Peretz – ADU Expert
Joseph Peretz is the founder of Neo Builders, a company that specializes in designing and building ADUs (Accessory Dwelling Units) in Southern California. With over 20 years of experience in the construction industry, Joseph has developed a passion for building high-quality, sustainable, and affordable housing solutions for homeowners.

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