Joseph Eichler founded Eichler Homes to bring modernist architecture to the suburban masses during the postwar California building boom. His developments used architect-designed houses -- initially by Anshen and Allen, later by Jones and Emmons -- that were built cheaply enough to compete with conventional tract homes. Most were timber, using post-and-beam construction. But Eichler was curious about steel. In 1955, he commissioned Raphael Soriano to build a steel-frame house in Palo Alto, which came in at $7 per square foot, comparable to wood construction. The X-100 took the experiment further: Jones designed it with advice from Pierre Koenig, a Los Angeles architect experienced in steel construction, and the house structure was prefabricated for rapid assembly.

The house has three bedrooms, two living rooms, and a kitchen arranged around the perimeter, with a central utility core containing bathrooms and laundry. The thin steel supports and glass sliding doors along the entire rear facade create a sense of openness that timber construction would have had difficulty matching. The beams protrude under the roofline at the front, and Jones turned down the steel decking to form a fascia -- a detail that gives the house its distinctive profile. Beyond the structure itself, the X-100 was designed to showcase advanced household appliances, some of them prototypes, as a vision of how Americans would live in the decades ahead. The grand opening on October 6, 1956, was as much a marketing event for the San Mateo Highlands development as it was an architectural demonstration.

Eichler sold the X-100 for $60,000 to Jesper Petersen, a furniture importer. The house changed hands several times before a group called X-100 Partners acquired it. One of the partners, Marty Arbunich, director of the Eichler Network, restored the house and became sole owner in 2013. In 2016, the X-100 was listed on the National Register of Historic Places, recognizing its significance as a pioneering experiment in residential steel construction. The roof, originally tar and gravel, has been replaced with sprayed polyurethane foam. The landscaping was designed by Douglas Baylis. In 2018, the house was made available for rent, allowing people to actually live in an experiment that is now 70 years old and still standing -- which, given what it was built to prove, is exactly the point.