ADUs & Additions in Rolling Hills Estates

City of Rolling Hills Estates Community Development Department, Building and Safety Division. Rolling Hills Estates is a contract city: its Building and Safety Division, part of Community Development at City Hall on Palos Verdes Drive North, uses Willdan for building and safety services, and application materials go to Willdan for building review only after Planning has approved the project. For ADUs and small additions, the city's submittal list asks for fully dimensioned plans showing existing and proposed lot coverage, plus one set signed by the homeowners association and the adjacent neighbors. Title 17 requires Planning Director grading approval for cut or fill between one and three feet deep or ten to twenty cubic yards of import or export, and Planning Commission approval beyond three feet, beyond twenty cubic yards or on any slope of 35 percent or more, although excavation for a swimming pool under a valid building permit is exempt. On lots in the H (horse) district, no permit may be issued that would rule out a future horse-keeping area of at least 800 square feet, set 35 feet from any dwelling on or off the lot and ten feet from a swimming pool, with a limited exception for legally built homes that cannot fit one until they are substantially expanded or rebuilt. We prepare the drawings, make the submittal and handle plan-check corrections ourselves, so you are not the one chasing plan check.

Single-family zones set minimum lots of one acre in R-A-E, 20,000 square feet in R-A-20, 15,000 in R-A-15 and 10,000 in R-A-10, on curving streets that follow the hillsides and mostly end in cul-de-sacs. Pools, spas, patios and decking count at 75 percent of their area toward a lot coverage cap of 25 percent in R-A-E, 30 percent in R-A-20 and R-A-15, and 35 percent in R-A-10, so coverage is often the first number a backyard plan is checked against. One local condition that shapes the work: The General Plan Safety Element maps more than 1,200 acres of the planning area as Altamont Clay Loam, Diablo Clay Loam and Montezuma Clay Adobe, expansive clay soils with a high shrink-swell potential, so pool shells, slabs and footings are best designed from a site soils report.

All of it, including Dapplegray Lanes, Rollingwood, Los Ranchos Verdes and Ranchview. Our crews run every job out of our Cahuenga Pass base in Los Angeles, with our own people on site.

Detached ADU: generally $150,000 to $400,000+ across Southern California. What moves it is square footage, finish level, utility runs, and site access; garage conversions typically run well below a ground-up detached build. We give line-item pricing after seeing the site rather than quoting a number over the phone.

Plan a realistic year. Design and engineering typically take one to three months, city plan check and corrections add several more, and construction usually runs four to eight months depending on size and site access.

Usually yes, and often substantially, because the foundation, walls and roof already exist. The trade-offs are that you lose the garage, and older slabs and framing sometimes need upgrading to meet current code.

California ADU law is designed to allow long-term rental, and an ADU is one of the few ways to add rentable square footage to a single-family lot. Short-term rental rules vary by city, so confirm your local ordinance before counting on that income.

Yes. Plans, engineering, Title 24 and the city submittal are all handled in-house, including responding to plan-check corrections. That is a service we sell on its own, so it is not something we hand off.