Home Building Services in Ventura County & Los Angeles

We build custom homes, room additions and accessory dwelling units (ADUs). Our design and construction teams work under a single roof, so planning, permits and building happen under one contract.

Custom homes and ground-up builds start at $650 per square foot and up. Room additions generally start at $450 per square foot, and smaller additions can run up to about $650 per square foot. New detached ADUs generally run $220,000 to $350,000. Larger or more complex projects can also run higher, and your written estimate confirms the exact price.

Builds can also take anywhere from 3 months for a home addition to up to a year for a new custom home, depending on your project. Design and permits come first, and permit timing depends on your city. For ADUs, we guarantee completion within 3 months of the first day of construction.

Yes. We handle the permits and approvals, including plans, submittals to the city or county, corrections and inspections, so you do not have to manage the paperwork.

Yes. RnD Builders is a licensed California general contractor, License #1081122, and you can verify it on the CSLB website. California requires a license for projects that need a permit or total $1,000 or more, so always ask any contractor for their license number.

With design-build, one team handles planning, engineering, permits and construction under one contract. There is no handoff between a separate architect and contractor, so decisions are made with the cost and the build in mind.

Often, yes. Hillside lots need additional engineering and foundation work, which we plan from the start and include in your estimate. The first site visit tells us what your lot requires.

An addition adds space to the house you have, an ADU adds a separate living unit on your property. A custom home replaces or builds from the ground up. The right choice depends on your lot, your goals and your budget, and we walk through the options at the consultation.

Often yes, depending on the scope. Additions are built so the existing home stays usable where possible. We plan the schedule and any short disruptions with you before work starts.

The main swing items are site conditions, soil, utilities and finish level, so we review them early. We quote from the exact scope you approve and itemize it, so you can see where the money goes. Site conditions are checked on the first visit, and any change is agreed in writing before it is added, so the project stays in line with the budget agreed in your contract.

Quality assurance is its own phase. We also check every part of the project, make adjustments if anything falls short, complete a walkthrough with you, and hand over the documentation and information for your new construction.

Yes. Our RnDesign team prepares the plans, renderings and engineering, so design and construction stay connected from the first sketch to handover.

Added or newly built space can improve how a property works and what it can offer, such as rental income from an ADU. The return depends on your market, design and the quality of the build, so we do not promise a specific amount.

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 homes, additions and 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.