ADU Builder in Ventura County & Los Angeles

An Accessory Dwelling Unit, or ADU for short, is an additional unit on a single-family property that may or may not be attached to the main building. These ADUs are fully independent living spaces equipped with their own electrical sub-panel, air-conditioning and heating unit, plumbing and hot water unit, kitchen, and bathroom. RnD Builders has completed many ADU projects across West Hills, Woodland Hills, Thousand Oaks & the Greater Ventura County Area. The ADU projects range from small garage conversions to an independent, standalone unit on the property of the main building.

A garage conversion works by converting the space currently occupied by your garage into a usable living space for you. That living space can be various things, such as an office, an art studio, or an additional bedroom. It can also be used as an ADU, but it must meet specific requirements to be considered. ADUs must have their own electrical sub-panel, air conditioning and heating unit, plumbing and water heater, and kitchen and bathroom areas. While ADUs are most commonly converted from garages, they can also be in other parts of the house, such as an attic or a detached addition to the home.

As an ADU builder, we price by the type of unit you build. New detached ADUs generally run $220,000 to $350,000, and garage conversions typically run $140,000 to $200,000. Larger units, difficult sites and higher finish levels can also run above these ranges. Your written estimate itemizes permits, utility connections and design so you can see each part of the price.

We guarantee your ADU will be finished within 3 months of the first day of construction. Design, plans and permit approval happen before construction. Your project manager gives you a personalized timeline and estimated finish date once the design is final.

Yes. All ADU projects require a permit for compliance with local regulations. We know local codes, safety standards and California ADU laws. We handle the entire process, from plans and permit filing to final inspection. Our local expertise helps us keep designs in line with regulations so approvals move quickly.

A detached ADU can be up to 1,200 sq ft. An attached ADU can be up to 50% of the main home or 1,200 sq ft, whichever is less. A junior ADU (JADU) can reach 500 sq ft and must sit inside the existing home or garage. Detached ADUs can generally be built up to 16 feet tall, with allowances up to 25 feet in certain zones, and ADUs under 750 sq ft are exempt from local impact fees.

Yes. California law does not allow cities to require owner occupancy for a standard ADU, so you can rent the ADU while living in the main home, or rent both. Rent and notice rules still apply, and your city may have its own requirements, which we help you understand before you build.

In many cases cities cannot require parking for an ADU. For example, no replacement parking is required when a garage is converted into an ADU, and parking is often not required near public transit. Rules depend on your lot and city, so we check them during design.

Often, yes. A legal ADU is a fully independent living space with its own electrical sub-panel, plumbing and hot water, and heating and cooling. Depending on your lot, you may need new water, sewer and electrical connections, and these can also add cost. We itemize them in your written estimate so there are no surprises.

Yes. California requires a contractor license for any project that needs a building permit or totals $1,000 or more in labor and materials, and every ADU needs a permit. RnD Builders is a licensed general contractor and ADU builder, and you can verify any license on the CSLB website before you hire.

Your written estimate lists the scope, each selection and the permit, utility and design costs. We also review site conditions that can change the job, such as soil, utility distance and access. If something changes, you approve it in writing before we add it to your contract.

The California ADU grant of up to $40,000 came through the CalHFA ADU Grant Program to help eligible homeowners cover early costs such as design, permits, soil tests, site preparation and energy reports. It was a grant, not a loan, but the funding ran out in late 2023 and the program is not currently accepting new applications. Some local city programs in the Los Angeles area may still offer help. We help you find the best available options before you start building.

It can. An ADU adds usable living space, rental potential and flexibility for family, and many buyers value it. Adding an ADU can also raise your property taxes and insurance needs. The return depends on your market and the quality of the build, so we do not promise a specific return.

As a local ADU builder, Ventura County is our main focus, such as Thousand Oaks, Newbury Park, Camarillo, Santa Rosa Valley, Oxnard, Ventura, Simi Valley and Moorpark. We also build ADUs across Los Angeles County, including Westlake Village, Calabasas, Agoura Hills, Malibu, Woodland Hills, West Hills, Chatsworth, Northridge, Porter Ranch, Santa Clarita, Valencia, Pacific Palisades, Pasadena, Altadena and the South Bay. Ask us if you are not sure we cover your address.