Mid-century modern Eichler X-100 house with steel facade and lush surroundings in San Mateo.

Eichler X-100: Iconic Steel House in San Mateo Highlands Resurfaces on the Market

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Written by Seth Sebastian

2026-10-13

Revisiting a Modernist Masterpiece: Eichler X-100 San Mateo

The iconic dwelling, nestled in San Mateo Highlands, is once again capturing attention as it returns to the real estate market. Originally designed in 1956 by architects A. Quincy Jones and Frederick Emmons, this house was a pioneering project for developer Joseph Eichler. Known for his wood-framed family homes, Eichler used this steel-framed prototype to explore revolutionary residential construction possibilities.

Exterior view of the Eichler X-100 showcasing its distinct geometric design.
Eichler X-100

Architectural Innovation and Design

Described in its launch brochure as a “new living form,” the X-100 served as a venue to experiment with cutting-edge design concepts, materials, and construction techniques. Featuring exposed steel, generous glass expanses, garden courts, and built-in furniture, the house seamlessly integrates indoor and outdoor environments. These modernist elements captured the imagination of over 150,000 visitors shortly after its unveiling.

For more innovative architectural designs, explore Surreal Italian Alpine Bunkers Transformed by Time to see how structures can be altered by nature over time.

Interior of Eichler X-100 with open layout and mid-century furnishings.
(Image credit: Sabrina Huang, Boyenga Team. )

A Glimpse Into the Future

Spanning 2,310 square feet, this modernist masterpiece comprises three bedrooms, two expansive living areas, and an open kitchen. Two bathrooms are centrally situated, while interior gardens introduce natural elements throughout the home. Glass sliding doors along the rear façade enhance the sense of openness with stunning views of the Santa Cruz Mountains. This steel house is a prime example of modern architecture.

Detailed view of Eichler X-100 exterior, highlighting steel construction and angular shapes.
Eichler X-100

Historic Recognition and Restoration

Selling initially for $47,000 in 1957, the house has changed hands among three additional owners. Listed on the National Register of Historic Places in 2016, it’s the only Eichler home with this designation. Under the X-100 Renewal Project, it was faithfully restored to its original condition. Current owner Marty Arbunich, director of the Eichler Network, occasionally opens the home for educational tours, preserving its legacy.

Architectural details of Eichler X-100, emphasizing its unique steel structure.
Eichler X-100

Now available via Boyenga Real Estate, the residence stands as a lasting testament to the modernist ideals that shaped Californian architecture, inviting yet another custodian to contribute to its storied history.

Mid-century modern Eichler X-100 house with steel facade and lush surroundings in San Mateo.

Source: wallpaper.com

Frequently asked questions

What makes the Eichler X-100 house architecturally innovative?

The Eichler X-100 house features exposed steel, generous glass expanses, garden courts, and built-in furniture, integrating indoor and outdoor environments. It was described as a “new living form” to experiment with cutting-edge design concepts, materials, and construction techniques.

When was the Eichler X-100 house listed on the National Register of Historic Places?

The Eichler X-100 house was listed on the National Register of Historic Places in 2016, making it the only Eichler home with this designation.

Who opens the Eichler X-100 house for educational tours?

The current owner, Marty Arbunich, director of the Eichler Network, occasionally opens the home for educational tours, preserving its legacy.