The architect’s design called for a three-level home cantilevering out over a 35-degree hillside in Beverly Hills, with floor-to-ceiling glazing along the downhill side and a 20-foot cantilevered viewing deck on the upper level. The geotech report flagged expansive clay near the surface and competent bedrock at varying depths — a common combination on Mulholland but one that punishes any foundation system that doesn’t respect both conditions.
Compounding the challenge: a tight construction window, sensitive uphill neighbors, and a budget that didn’t have room for the kind of overdesign that often happens when engineers get conservative on hillside work.
We designed a foundation system using twelve 24-inch diameter caissons drilled to competent bedrock — depth varied from 18 to 32 feet across the site. Grade beams tied the caissons together and isolated the structure from the expansive clay above. This decoupled the building from the soil conditions that would have caused problems with a more conventional foundation.
The cantilever was handled with a steel transfer system at the upper-floor level — a single W24 spanning across three caisson lines, with moment connections at each column. We kept wood-frame construction for the rest of the structure, so the steel showed up only where it earned its place. The result is a building that looks like a wood home, structurally performs like an engineered one, and didn’t blow up the GC’s budget on imported steel.
Plan check approved the structural set in two rounds — one set of corrections, which we returned within 72 hours. The architect kept the original ceiling heights. The cantilever reads as designed.
"They engineered the building we actually drew. The cantilever reads exactly like the rendering — without surprise costs."
Construction completed in 14 months, on the original schedule. The structural scope came in within budget — no change orders driven by structural conditions. The cantilever performs as designed. The owners moved in.
And on the architect’s next hillside project, we got the call before the design was finished.