Accessory Dwelling Units

Building Space & Increasing Opportunity on Your Existing Property

Who We Are

ADU Garage Experts is one of the top structural engineering firms in Southern California. We specialize in drafting additional dwelling units (ADU’s), which increases the value of a property and provides more living opportunities for our clients.

As a special division of the structural engineering firm, Peter Erdelyi & Associates, ADU Garage Experts is uniquely equipped to help you plan and execute your next home or investment project. We have the best team of structural engineers, drafters, expeditors and project staff, who will deliver plans that withstand the test of time. We also have trusted contractors who we work with to complete your construction efficiently and on schedule.

Peter created ADU Garage Experts because of the high demand for ADU’s in Southern California, though his team’s expertise ranges from ADU’s to multi-million dollar corporate buildings. We are well equipped to help you make the most out of your property investments.

Let ADU Garage Experts help you understand the benefits of an ADU. Let's plan your next investment opportunity or major home project to fit your lifestyle needs.

(310) 553-9339

What is an ADU?

ADU stands for Accessory Dwelling Unit. The state of California defines an ADU as “an attached or a detached residential dwelling unit on the same lot as an existing dwelling unit zoned for single-family or multifamily use that provides complete independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation on the same parcel as the single-family dwelling is situated.”

There are three types of ADU’s: Converted, Attached, and Detached.


The conversion of a previously non-livable space, typically a garage, into livable space.


An existing dwelling is adapted into two separate living spaces, each with their own separate entry. You can convert up to 50% of a primary dwelling space to be its own separate unit. A great example of this is making one large house into a duplex.


A separate dwelling that has been constructed on a property that often times has its own entry and exit. The most common Detached ADU’s are guest houses.

Do you know if your property qualifies for an ADU? Learn more about ADU conversion rules or contact us today to discuss the options for your property.

Why Build an ADU?

There are many benefits of building an ADU. An ADU can increase your property value, provide you with extra square footage for that needed space, or be a rental investment.

A simple garage conversion (400 sq. ft. at $495/sq. ft.) could add up to $198,000 to the value of your property.

Here are some of the different ADU's we've built for clients over the years:

Additional Benefits of an ADU


ADUs provide much needed housing in Los Angeles, where there is currently a housing shortage that is making housing inaccessible to many who need it. ADUs use existing governmental services — such as sewers, roads, schools – and reduce the demand for additional and expensive infrastructure.


ADUs provide housing with a small environmental footprint for people whose needs are met by a small living space. New ADUs provide rental housing that is 33% to 44% smaller per capita than standard, new single family rental units. This means new ADUs provide housing at a fraction of the cost of energy in the construction, deconstruction and habitation over typical single family rental units.


ADUs provide more housing options in family-oriented neighborhoods without dramatically changing the overall character of the neighborhood as newly constructed single family apartment buildings would. Plus, ADUs help keep families together and provide options for home owners to stay in their own home. Some empty nesters build ADUs and move into the unit themselves, renting out the main home.

Find out today if your property qualifies for an ADU and get more details about the process of converting a portion of your property to an ADU.