In 2009, architect Daniel Lopez-Perez and his wife, designer Celine Vargas, began looking for a way around what they saw as the shortcomings of conventional homebuilding. Stick-frame houses were slow to construct and, in California, increasingly vulnerable to fire. “What building technology can we leverage to build housing that is smarter, faster, and more resilient?” the couple asked.
More than a decade later, in 2021, they offered an answer. Their company, Polyhaus, is a San Diego–based design and building technology startup that develops prefabricated homes from cross-laminated timber (CLT). The system, which relies on mass timber panels robotically cut and assembled on-site, aims to produce durable homes in a fraction of the time required for traditional construction.
The first test of the concept came in their own backyard in La Jolla: a 540-square-foot accessory dwelling unit, or ADU. Known as the Tetra-One, the small structure was completed quickly and designed to resist fire—proof, Lopez-Perez and Vargas believed, that their patented system could be scaled up. Since then, Polyhaus has expanded its offerings to include models as large as 2,500 square feet.
Building Blocks in Timber
Polyhaus’ system is centered on CLT, a material gaining traction in the U.S. construction industry. Panels are made by layering and gluing boards of Douglas fir at right angles, producing sheets that are both dimensionally stable and slow to burn. According to industry specifications, CLT can burn at a nominal rate of about 1.5 inches per hour, giving it far more fire resistance than typical two-by-four framing.
For Polyhaus, those panels are milled into exact puzzle-like pieces. The Tetra-One, for instance, uses just 64 pieces that can be assembled within days. The company wraps the timber in insulated metal panels for added fire resistance and energy efficiency.
The geometric form of the homes—based on truncated polyhedrons—also reflects a kind of functional design idealism. The shapes maximize interior volume while minimizing land use, and, according to the founders, create aerodynamic exteriors less prone to wind-driven wildfire spread.
A Different Kind of Prefab
Prefabricated housing is not new, but Polyhaus positions itself at a junction of urgency: the state’s housing shortage and the rising risks of climate change. California has committed to building 2.5 million new housing units by 2030. At the same time, wildfires in the state have destroyed more than 100,000 structures since 2005, according to state figures.
The Tetra-One, starting at $300,000, is the company’s entry point. Larger models—the 980-square-foot Tetra-Two and 1,165-square-foot Tetra-Three—begin at $400,000. Prices vary by site and finishes, but include design, engineering, fabrication, delivery, and installation. Clients can customize cladding colors and interior finishes, though the building form remains fixed.
So far, the homes are available for shipping anywhere in the continental United States, and the Tetra-One is pre-permitted in San Diego County. The company’s stated goal is to expand nationally, with ambitions for international reach.
Polyhaus says the entire process, from deposit to move-in, can be completed in about six months. The timeline begins with site feasibility studies and contractor bids, followed by permitting and then off-site fabrication. Local contractors finish the installation.
The company sources its timber from restoration projects in Washington’s Colville National Forest, linking each build to healthier ecosystems. Founders Daniel Lopez-Perez and Celine Vargas see this as part of a bigger mission: combining advanced engineering with environmental responsibility to rethink how homes are built.
What began as a backyard prototype in La Jolla has since evolved into a system of fire-resistant, cost-conscious dwellings that can be assembled in days—a compact but telling blueprint for housing in an era shaped by scarcity and wildfire risk.