Mill Valley, California

Site Size: 8,210 square feet

Project Size: 1,487 square feet

Program: A family in Mill Valley, California had Japanese firm Koji Tsutsui & Associates design a structure that would function as both an office and a home so the family could spend more time together.

Solution: Since the property, situated at the edge of a steep, heavily wooded slope near a Bay Area national park, is replete with wildlife, Tsutsui wanted to minimize the building’s impact on the natural habitat. Tsutsui designed the house as a cluster of 10 wood-framed volumes lifted off the ground on stainless steel columns.

Visitors enter the house at the crest of the hill, where a path from a garage leads to the house. From here, the cascade of boxes follows the contour of the hill. Inside the interlocking volumes, an uninterrupted path fosters interaction between family members.

The upper level spaces include two bedrooms, a study, a kitchen and dining area, a living room, and access to a rooftop terrace. The lower level, also accessible by an entry at the south side, contains a foyer, a living area, and another bedroom. Interiors are minimal, with small sections of plywood steps leading to each separate cube space like a terrace.

Koji Tsutsui & Associates
Address: 3-28-10-304 Kyodo Setagaya-Ku
Tokyo, 156-0052


Koji Tsutsui

Koji Tsutsui & Associates
Address: 3-28-10-304 Kyodo Setagaya-Ku
Tokyo, 156-0052

Personnel in architect's firm who should receive special credit:
Koji Tsutsui (Partner in Charge ' registered architect in Japan)
Satoshi Ohkami (Project Manager ' not registered architect)

Structural Engineer:
Jon Brody Structural Engineers

Civil Engineer:
AYS Engineering Group, Inc.

Title 24 Compliance:
Gabel Associates, LLC

Geotechnical Consultant:
Herzog Geotechnical

General contractor:
Radco & Associates, Inc.

Iwan Baan



Structural system
Concrete Foundation, Steel Piloti, Wood Framing.

Exterior cladding
Minerit HD (American Fiber Cement Corporation)

Moisture barrier:
WallShield (VaproShield)

Built-up roofing:
Modified Bitumen Class 'A' Roof Assembly

Metal frame:
AlumaTherm, Inc.

Insulated Glazing

Wooden Doors

Interior finishes
Floor and wall tile:
Grade-A Plywood with white-wash stain finish