The Canyon ADU
Backyard build · canyon hillside · 640 sqft · 18 weeks
the assignment
A backyard ADU for aging-in-place parents on a sloped Topanga lot. Needed to clear hillside ordinance height limits, preserve a heritage coast live oak, and meet Chapter 7A fire assemblies for the Very High Fire Hazard Zone.
Spec sheet —
- Cladding
- 1×6 western red cedar over ignition-resistant sheathing
- Roof
- 24-gauge standing-seam steel, Class A
- Heat
- Mitsubishi heat pump, single zone
- Windows
- Marvin Essential, dual-pane tempered
- Permits
- LA County PW BLD2023-01188
Challenges
- 12% slope across the building footprint
- Heritage coast live oak with a 22 ft drip line
- Very High Fire Hazard Severity Zone — Chapter 7A everything
Solutions
- Pier-and-grade-beam foundation, zero excavation under drip line
- Cedar rainscreen with ignition-resistant backing + Class A standing-seam roof
- Heat-pump HVAC + solar-ready conduit + ember-resistant vents on day one
Timeline
18 weeks · 5 milestones · 2024
- Week 1–6Apr 3
Permits, survey, tree protection plan
- Week 7–9May 15milestone
Foundation, underground utilities
- Week 10–13Jun 5
Framing, dry-in, windows
- Week 14–16Jul 3
MEP rough, insulation, drywall
- Week 17–18Jul 24milestone
Finishes, final inspection, occupancy
“We worried it would feel like a backyard box. It feels like a real house.”