An ADU is the most effective way to add real square footage to a Los Angeles County property — rental income, space for family, or a home office that isn't a converted bedroom. California law has made them far easier to permit than they were a decade ago. But easier to permit is not the same as simple, and the projects that go badly are almost always the ones that started without a clear picture of the work.
Start with the lot. Setbacks, existing structures, sewer and water line locations, panel capacity, and slope all decide what's actually buildable. A detached ADU on a flat Santa Clarita lot with an accessible sewer line is a very different project from one on a Sherman Oaks hillside that needs a retaining wall and an upgraded electrical service before the foundation is even poured. This is why our first visit is a site review, not a sales pitch.
Then plans and permits. You need drawings your city will accept, and depending on scope, structural engineering. Permit timelines vary widely between jurisdictions — the City of Los Angeles, Santa Clarita, Burbank, Glendale, and Pasadena all run their own process. We coordinate the drawings and pull the permits so this stage doesn't stall for months while you wait on a designer who isn't returning calls.
Construction itself follows a predictable order: foundation, framing, roof, rough plumbing and electrical, inspection, insulation and drywall, stucco, then finishes. The sequencing is where general contractors earn their keep. When the plumber, electrician, framer, and stucco crew all work under one contractor, nobody is waiting two weeks for a sub who took another job.
Budget honestly, and treat any estimate that seems dramatically low as a warning. The cheap bid usually means something was left out — utility upgrades, drainage, engineering, or the finish level you actually wanted — and it reappears as a change order halfway through.
Thinking about an ADU? Call ACA General Construction at (818) 326-5592 for a free site review and written estimate anywhere in Los Angeles County.