transforming the 1962 hillside home in Mill Valley

transforming the 1962 hillside home in Mill Valley

“Often when thinking about preserving a thing—a structure, an object, a landscape, a city—one talks about preserving its ‘heart’ or its ‘core’. But in this case, it was the opposite—we were trying to preserve the periphery, while completely reimagining the core,” says SAW co-principal Dan Spiegel.

Very rarely do unusual and somewhat radical ideas like this make it off the page. This was not the case with The Middle Half house in Mill Valley, United States. San Francisco-based Spiegel Aihara or SAW was very successful in taking a congested 255.1117 sqm home with apportioned rooms and dramatically opening its core to create interiors that are awash in natural light and flow into the surrounding landscape. Post transformation the home enjoys a larger 321.1658 sqm space that boasts an open-plan central living space connecting to its surrounding sceneries.



  • Front façade at the street level; rear façade facing the alley | The Middle Half | SAW | STIRworld
    Front façade at the street level; rear façade facing the valley Image: Mikiko Kikuyama






  • Section showing progression of levels from the street side to the valley facing side | The Middle Half | SAW | STIRworld
    Section showing progression of levels from the street side to the valley facing side Image: Courtesy of SAW



SAW makes this connection between the inside and the outside spatially as well as with the materials they use in the residential architecture. The façade design of the house at its front starts on the street level and drops two levels at the rear end of the house where it faces a steep green valley. The front façade hangs low and is well rooted to its surroundings. Once inside, the new circulation path visually connects the entryway to the rear deck of the house and becomes the spine connecting the more public areas such as the living room, dining room, family room, kitchen, and the outdoor deck. The more private areas such as bedrooms, bathrooms, guest suite, and offices are placed to the left and right of this central axis. “A basic premise of the design is to use a landscape gesture—a corridor between the front yard and the valley views—to resolve the tension between building elements,” says SAW co-principal Megumi Aihara.



First floor plan with the central axis | The Middle Half | SAW | STIRworld
First floor plan with the central axis Image: Courtesy of SAW


The kitchen and dining area enjoy open tops with the use of strategically placed skylights in the exposed beam ceiling. This open dining-kitchen area also flows into the living rooms and family rooms that are lined with floor to ceiling windows and glass doors opening into the rear deck to reinforce openness of the core and continuity of spaces into the landscape.



  • Kitchen and dining space with a living edge dining table | The Middle Half | SAW | STIRworld
    Kitchen and dining space with a living edge dining table Image: Mikiko Kikuyama






  • Kitchen with a skylight and exposed beam ceiling| The Middle Half | SAW | STIRworld
    Kitchen with a skylight and exposed beam ceiling Image: Mikiko Kikuyama



The private spaces such as the primary bedroom and bathroom are also spatially and visually connected with the outdoors. The bedroom opens into the lush front garden through the use of a new 16-foot-wide sliding door and the bathroom connects with the camphor tree in the front yard with a window.



Bedroom opening into the garden with a glass sliding door | The Middle Half | SAW | STIRworld
Bedroom opening into the garden with a glass sliding door Image: Mikiko Kikuyama


SAW amends the lack of a connection between the upper and lower level of the interior design by tucking away a stairwell behind the open bookshelf in the family room. It leads to a bar/lounge, guest room, and office. The lounge mirrors the connections on the upper level and features floor-to-ceiling sliding glass doors that open into the lower deck. The wide upper deck, the lower deck, and the lowest deck featuring the swimming pool, are all connected by a robust cedar staircase.



The lounge with the connecting staircase | The Middle Half | SAW | STIRworld
The lounge with the connecting staircase Image: Mikiko Kikuyama


The use of textured materials such as rough-sawn cedar cladding, cast in place concrete, and galvanised steel is strategic and ingenious as this particular combination of materials successfully roots the home in its surroundings without letting it get lost in the landscape. This is not an easy task as the landscape itself is spectacularly designed in levels featuring a myriad of plants such as an array of azaleas, lilies, and grasses that lend a textural and visual depth to the entire setting. The building materials used in the landscape architecture highlight this fluid and charming landscaping by visually framing it.

“The most critical building elements—the steel and wood beams and columns—break free of the constraints of the interior walls to carve out and define volumes of exterior space, framing views as pictorial scenes,” says Aihara of the connection between residential design and landscape design across the project.



The visual and spatial connection between the inside and the outside | The Middle Half | SAW | STIRworld
The visual and spatial connection between the inside and the outside Image: Mikiko Kikuyama


The interiors of the private residence, designed collaboratively by SAW and one of the homeowners and interior designer Kina Ingersoll, is a reflection of the envelope. The floor-to-ceiling white millwork, crisp gypsum wall, and the reclaimed white oak flooring create a sense of buoyancy which is further accentuated with fixtures like the long-stemmed pendant lights hanging over the minimal kitchen bar. The furniture, such as the live edge dining room table is carefully selected by Ingersoll to further this feeling of lightness. 

Editing the core of the building without losing its soul is not an easy task but SAW managed it beautifully by connecting the deepest insides of the home to its outsides. The result is a much more refined and open, yet rooted home.



Inside meets the outside across all levels | The Middle Half | SAW | STIRworld
Inside meets the outside across all levels Image: Mikiko Kikuyama


Project Details

Name: The Middle Half

Location: Mill Valley, USA

Area: 321.1658 sqm

Year of completion: 2022

Architect: Spiegel Aihara Workshop (SAW)

Architecture & Landscape Architecture: SAW

General Contractor: Perfection Construction

Structural Engineer: GFDS

Civil Engineer: Benjamini Associates

Millwork: Marco Hernandez Custom Cabinetry

Geotechnical Engineer: Nersi Hemati

Interior Design: Kina Ingersoll