Condominium One at The Sea Ranch: Ten Homes, One Architectural Idea

By Matthew Martinez, Founder, CEO & Managing Broker, Diamond Real Estate Group. California DRE #01869679.

The Sea Ranch is often pictured through a single weathered house set against grass and ocean. One of its most influential early buildings tells a more collective story: ten homes brought together into a compact architectural group.

Condominium One makes the relationship between a residence and its surroundings the central design question. Its importance lies in how a cluster of homes can form a place while leaving room for landscape.

A demonstration of the development’s ambitions

Turnbull Griffin Haesloop’s project archive credits Moore, Lyndon, Turnbull and Whitaker with the 1965 design. The firm describes ten model units grouped closely to encourage community and retain as much open site as possible.

The archive also records the project’s National AIA Twenty-Five Year Award. That recognition concerns enduring architectural quality, suggesting a design whose influence continued well beyond its initial presentation.

The compact arrangement is an important part of that legacy. Open space and residential density were treated as connected decisions. Bringing buildings together could make room elsewhere for the setting that drew people to the coast.

The building works with a changing landform

The National Register nomination describes a heavy timber-frame building wrapped in redwood siding. Its form rises with the slope from the cliff edge and culminates in a pair of towers.

The nomination identifies the work with the Modern Movement and the California Third Bay Region tradition, including its role as a vernacular Shed prototype. These classifications connect a distinctly modern building with an interest in regional materials and familiar forms.

The resulting architecture offers something more specific than a general preference for wood. Structure, surface and silhouette work together, so the group has a recognizable presence without needing an ornamental façade.

For someone interested in coastal homes, this is a valuable design lesson: a building’s relationship with a slope can be as expressive as its finish materials.

The original planning vision had several residential patterns

The Association’s fiftieth-anniversary historical essay describes a wider planning team led by landscape architect Lawrence Halprin. Studies of ecology, soils, wind, sun, forest and water informed the early concepts.

Within that vision, single-family houses were associated with protected locations near cypress hedgerows. The narrow, treeless southern area was envisioned with condominium groups and sheltered courtyards.

The distinction explains why Condominium One should be understood as a particular response within The Sea Ranch. Its compact form was one way of relating housing to local conditions, alongside other building patterns.

The essay also records the tension between early ideas and later development. That history makes the surviving demonstration building especially useful: it preserves a clear expression of one ambitious approach.

Architectural recognition attaches to a residential place

The National Park Service listing records Condominium One’s addition to the National Register on July 29, 2005, with 1965 as its significant year.

The homes remain a residential setting. Enjoying the architecture therefore includes respecting household privacy and using appropriate public routes.

For people considering The Sea Ranch, the project supplies a more precise vocabulary than simply calling a home coastal or modern. It brings attention to clustering, shared land, section, shelter and the way individual rooms contribute to a larger composition.

Those ideas help explain why a small group of homes has remained such a large part of the community’s architectural identity.

A shared composition can give each dwelling a distinct role while making the whole landscape easier to understand.

Explore real estate and home for sale in The Sea Ranch, or contact Diamond to discuss a location that fits your plans.

Sources checked October 28, 2026. Historical details are attributed to the linked primary records and site operators. Check the operator for current visiting arrangements.