Slope, soils, and street
The slope. The Baseline Hillside Ordinance governs single-family zones in the City's mapped Hillside Area. It sums the allowable floor area slope band by slope band, so the steep parts of a lot carry less house than the gentle ones, and it calls for a Slope Analysis Map, prepared by a registered civil engineer or licensed land surveyor, to measure those bands. LADBS determines whether the ordinance applies to your project. I read the parcel on ZIMAS before we meet so we start from the real envelope.
The soils. A hillside house stands on its foundation, and the foundation stands on the geotechnical report. Caissons, grade beams, retaining walls, and drainage are drawn from that report. I bring the geotechnical engineer into the design team early, because a foundation redesign at plan check costs months.
The street. Bel Air streets are narrow and they wind. For a new home on a lot fronting a Substandard Hillside Limited Street with a roadway narrower than 20 feet, the code withholds the building and grading permits unless the project is approved under Section 12.24 X.21, and the route to your driveway is checked as well. I measure the street, plan the delivery route, and size the trucks before the schedule is set.