This 2,500-square-foot home called the Yosemite Lake House was built to reduce wildfire risk in steep, uneven terrain in a wildland-urban interface. Built using ICFs from Fox Blocks by Airlite Plastics Co., the home is a wood-free, fully noncombustible Type IA building per code. It was completed in less than one year and on budget for the same cost as it would have been had it used wood construction. Out of 48 weeks of construction time, the ICF installation took 150 days. The home was the 1st Runner Up and People’s Choice Winner in the Small Residential category of the 2026 ICF Builder Awards.
“The Yosemite Lake House demonstrates that Type I-A, fully non-combustible construction is both feasible and practical for single-family homes built with ICF,” Fisher said. “Located in one of California’s most fire-prone regions, it provides a model for resilient housing in the wildland–urban interface — delivering safety, durability, and energy performance well beyond conventional wood-framed construction.”

Construction and Site Issues
The home was built on a steep, rocky hillside just outside Yosemite National Park, and access to the site was limited. All materials and equipment had to be carefully staged and delivered. It also marked the first installation of a patent-pending system called PHNX Longspan, a fully wood-free roof and floor framing system that integrates exclusively with ICF walls. “The system allows long, open spans without the need for structural sheathing — maintaining a 100% non-combustible structure,” said Laurie Fisher, architect and builder with PHNX Development. The project incorporated more than 200 cubic yards of concrete placed in nine separate pours, requiring precise sequencing and coordination on a difficult site.
PHNX Development is a design-build company focused on helping people rebuild resilient homes. “ICF is a non-negotiable component of a PHNX Home,” Fisher said. “People come to us for a fully wood-free, Type IA noncombustible home and it wouldn’t be possible without using ICF.”

Design & Sustainability
The Yosemite Lake House is an all-electric, net-zero energy home with an R-30+ envelope. A zoned, compact-ducted mini-split HVAC system provides precise comfort control, while a whole-house fan provides continuous fresh air, 24/7, regulating humidity and maintaining healthy indoor conditions. The design maximizes natural daylight to reduce lighting demand and integrates LED fixtures throughout.
Construction generated more than 80% less waste than a comparable wood-framed build. “Built entirely without wood, the home eliminates the potential for rot, mold, or pests that require chemical treatments — enhancing durability and indoor air quality for the life of the building,” said Fisher. “The result is a high-performance, net-zero home with no energy costs.”

The project was featured on local television stations and serves as inspiration for builders, insurers, and public agencies exploring scalable wildfire-resistant solutions. The home was insured by Mercury Insurance as a Type I-A non-combustible home with an annual premium of just $1,300, demonstrating the tangible financial benefits of fire-resilient design. “This home proves that building with ICF is not only easier, more sustainable, more fire safe, and more durable, but that it also doesn’t have to cost more than traditional wood frame construction,” said Fisher.