The building industry is conducting two parallel conversations—Passive House and fire hardening, using different vocabularies to describe a fundamentally shared ethos. This talk argues that airtight envelopes, sealed penetrations, and continuous insulation architects have long detailed for Passive House performance are simultaneously accomplishing the work of fire hardening. Drawing on a retrofit underway in Pacific Palisades during the January 2025 fires and on new-construction prototypes developed for Altadena rebuilds, Marcos Santa Ana of Alloi Architecture + Construction traces the disciplinary overlap and its practical implications.
Learning Objectives
- Why ember intrusion—not direct flame contact—accounts for most structure losses in California WUI fires, and which architectural details address the vulnerabilities that make it possible
- How Passive House detailing maps directly onto fire-hardening requirements across the building envelope
- Assembly specifications for roofs, walls, glazing, vents, and crawl spaces
- Layered active systems—cistern-fed perimeter sprinklers, HEPA/MERV filtration, and backup generation—extend protection after the fire front passes
Presenter
Marcos Santa Ana, AIA, CPHD, GC is a licensed architect, licensed general contractor, and Certified Passive House Designer, and the founder of Alloi Architecture + Construction, an architect-led design-build studio in Los Angeles specializing in high-performance homes. He serves as the AIA California state representative for the Small Firm Exchange, a board member of the California Passive House Network, and a facilitator for the Entrearchitect Architect as Developer group. Alloi brings experience from projects across 40 states—WUI rebuilds, adaptive reuse, high-performance new construction—to bear on the demands of Los Angeles. Through his sister company, Dihedral Development, Marcos extends that work into architect-led development, quietly transforming the city’s aging housing stock one high-performance home at a time.
