Rau Haus by Feldman Architecture: Sustainable Cottage in Portola Valley

The project was developed by architects Feldman Architecture, Rau Haus is a calm modern cottage located on the hills of Portola Valley, California. 3433 square feet of living space reflect the characteristics of the terrain with low environmental impact and eco-friendly design, allowing enjoyment of panoramic views of Coal Creek Open Space Preserve and distant views of the San Francisco Bay.

This L-shaped house was conceived as a secluded space for the family to avoid urban hustle and bustle. The clients, a couple with a young child, were looking for a peaceful sanctuary that provides both seclusion and space for guests. Feldman Architecture studio created a sculptural, naturally lit home where the boundary between interior and exterior spaces blurs.

Architecture in Harmony with Landscape

The house design softly integrates into the eastern slope, creating cozy interior courtyards and opening up unlimited views in all directions. The architecture is designed to minimize visual intrusion from neighboring lots while maintaining full immersion in nature.

Double height defines the kitchen and dining area, creating vertical connections with the Loft office and bedrooms on the upper level. Clerestory windows and light wells let in morning sun, providing privacy and close connection with nature.

The perpendicular part — a single-story building with a green roof, offers multifunctional space next to the pool terrace — an ideal place for sports, games and parties. The modern infinity pool blends with the cultivated area and wild meadow landscape, highlighting the architectural pursuit of seamless transitions.

Interior and Material Strategy

The material palette is based on modesty and durability. The second floor is covered with cement plaster, while the first floor uses locally restored Monterey cypress siding, left unfinished for natural aging. These elements are organized in clean geometric forms, smoothly transitioning from the exterior space to interior and maintaining a consistent modest modern aesthetic.

Inside, the finish is minimalist, allowing architectural form and surrounding nature to take center stage. From the main roof, guests can enjoy rare northern views of the bay — an important feature for owners who wanted shared access without compromising privacy of their primary bedroom.

Sustainable Living by Design

Rau Haus is designed to be beautiful and functional. The house features several eco-friendly technologies:

• 6.24 kW photovoltaic system, producing 9777 kWh/year

• Two Heliodyne solar panels, heating a 119-gallon tank

• All electrical appliances and heat pump heating system

• Passive solar strategies, including deep overhangs and interior windows

• Cross-ventilation through operable windows, skylights and doors

• Concrete with 30% fly ash, reducing carbon emissions

Additionally, external terraces provide varying degrees of shade throughout the day, increasing comfort and usability all year round.

Architectural Concept

"This project allowed us to create a space of tranquility, well-balanced in design that creates horizontal and vertical connections within and to the landscape," said Steven Step, AIA, lead project engineer.

"Under the calm design lies strict attention to form and space details, precisely worked within a carefully selected material palette," added Anjali Iyer, LEED AP, lead architect. "The house embraces the spirit of the site and creates a backdrop for everyday life."

Rau Haus is an elegant example of sustainable residential architecture, where materials, form and environment are seamlessly integrated — one of many complex projects by Feldman Architecture.

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