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Discover Frame House designed by Mork-Ulnes Architects

Frame House designed by Mork-Ulnes Architects
Photography by © Bruce Damonte

This 4,600 square foot home was designed by Norwegian/American architect Casper Mork-Ulnes after the former mansion on the property was damaged in a wildfire, which are now so common in the Sonoma Valley. The new house, which is perched on a terrace above a forested canyon and vineyards, is supported by a concrete framework that determines its structure and rhythm. Between the columns, which also serve to organize the internal areas, concrete shear walls are wrapped with a sacrifice layer of aging wood siding to protect the new house. This sturdy concrete structure provides a vantage point from which to view the land and beyond. The warm interiors of the house are lined with Douglas Fir, in contrast to the outside, which is covered in a fire-proof armor. The house connects the inside to the California climate in practically every room through an extroverted interaction to the California landscape. The interior is set up around a double-height space over the kitchen that unites the two floors and is divided by a floating catwalk that runs between the two bedroom wings upstairs. Discover more after the jump.

Frame House designed by Mork-Ulnes Architects
Photography by © Bruce Damonte

From the architects: Atop an idyllic perch in the Sonoma hills, a San Francisco based family had found the perfect retreat fortheir family and friends. In 2016 they had commissioned Mork-Ulnes Architects to design a compact, three-bedroom guesthouse to compliment the main house. Just after the guesthouse was complete, a wildfire engulfed the property.

The forested canyon and hills above were devastated, but the all-concrete guesthouse survived the event. Re-investing in the land after the property fell victim to this natural disaster was important to the owners who enlisted Mork-Ulnes Architects again, this time to design the main house, ex novo. The property is part of the rebuilding effort following the 2017 Nuns Fire, an unrivaled recovery driven by community resolve and eased by streamlined bureaucracy.

Impacted by the wildfire, which fortunately did not harm anyone, the owners were very concerned about fire protection for their home and family and insisted on fire resistant building materials from the onset of the design process. They requested a great room with an indoor-outdoor kitchen and dining area, living room with views towards the manzanita canyon, a media room, primary bedroom suite, two guest rooms, and a children’s bedroom with en-suite bath. The architects came up with a simple, two-story concrete structure based on a three-dimensional grid. Firmly planted on a plateau surrounded by Manzanita groves and pine-forested hillsides, the house sits right above the pool area and the previously completed concrete guesthouse.

Photography by © Bruce Damonte
Photography by © Bruce Damonte
Photography by © Bruce Damonte

The concept

The house is built on a structural gridwork that is not based on a fixed dimension but rather characterized by a combination of modules that vary slightly in width and that are filled in with either glass or wooden walls, depending on the function of the rooms beyond. The modernist matrix acquires in this way its own elegance and a capacity to interpret the relationship between interior and exterior. The gridwork supports a loggia, providing shade from the warm California sun and extending the function of the tridimensional framework of the building.

“After the Nuns Fire of 2017 ravaged the surrounding area and damaged the property, the clients asked us to design a new house that would be armored against future wildfires.The concept was to design an all concrete house that is wrapped in a sacrificial layer of wood that gave a nod to the local vernacular farm structures in the area – so that its materiality still feels like it fits with a Northern California home despite being structurally of concrete.”

Casper Mork-Ulnes

The building asserts its autonomy by means of a contemporary reinterpretation of modernist architecture that in California, especially through the Case Study program promoted by John Entenza in the 1940s, was particularly prolific. The modernist rigor is tempered by the warmth of the wooden infills, reminiscent of local vernacular rural constructions. The rhythm of the vertical elements anthe alternation between the opacity of the walls and the transparency of the windows reinforces the impression of graphic abstraction.

“Having lived in California for a very long time, I am influenced by the West Coast modernists, Koenig, Neutra, Ain and their contemporaries. Those houses, with their sense of openness, explore issues of light and space that are fundamental for me as well; as a Norwegian, I am always drawn to the psychological importance of light and air in architecture.”

Casper Mork-Ulnes

As a response to the clients’ request to have exterior access and views from every room, the house has three flanking public spaces on the ground floor and a central stair. The upstairs program is connected with a catwalk which dissects a central void, and a central hallway which pushes all bedrooms and bathrooms to the exterior to enjoy the views and terraces above the loggia.

Photography by © Bruce Damonte
Photography by © Bruce Damonte

The exteriors

While the guesthouse for the property is an all-concrete structure, the clients still wanted the warmth of wood on the exterior and interior of the home that they would be occupying. The entirely fire-resistant concrete shell is therefore clad in with a sacrificial surface layer of western red cedar siding as a nod to the vernacular agrarian architecture in the area as well as to soften its visual impact on the site.

All materials which face the natural environment are intended to resist the potential of wildfire: concrete structure, concrete masonry unit sheer walls, cement panel soffits, and non-combustible roofing material were chosen to armor the exterior. Windows are metal clad on the outside, though wood clad on the interior. A sprinkler system is integrated throughout the interior, and a solar field and power wall battery system are connected to the well and water supply pump to ensure function in emergency.

“A deep loggia and a repetitive grid of columns creates the structure of the house. The loggia creates both a respite from the hot Sonoma sun and a rhythmic pattern that provides the order and framework for the house. The grid structure defines the functions of the house and whether they are introverted or extroverted to the site depending on if they are filled in with a void of glass or solid wall.”

Casper Mork-Ulnes

The Northern, Eastern, and Western frontages of the building are defined by expansive glass openings, allowing for a sense of continuity with the outside environment as well as ample natural light. To mitigate major solar loads, deep concrete overhangs shield the windows along the Eastern and Western frontages and the Southern facade is entirely opaque. This creates a wellcalibrated balance of natural light to shade in both levels of the home.

Photography by © Bruce Damonte
Photography by © Bruce Damonte
Photography by © Bruce Damonte
Photography by © Bruce Damonte
Photography by © Bruce Damonte

The interiors

To add warmth and texture to the interiors, the main level is clad in bleached douglas fir, while concrete floors maintain the connection to the outdoors and provide a durable surface for kids running in from the swimming pool. The wooden stair connects the main floor to a double height void that views a wooden atrium space. A cat-walk, illuminated by a linear skylight, connects the two bedroom wings, which have painted gypsum board walls, wooden floors and doors, and which are dotted with wooden wall sconces reminiscent of mid-century California craft design. The bathrooms, clad in a warm honed cream limestone, have wooden vanities and mirrors framed in wooden fins harking to the kitchen cabinetry and framework architecture. All bedrooms and bathrooms have direct access to the expansive viewing decks above the Loggia, giving the clients and their guests space to contemplate the expansive views of the Sonoma Valley and wooded canyon below.

Designed and curated by the Office of Charles De Lisle, the interior furnishings and decorative lighting reflect the client’s wish to compliment the minimal architecture by adding bold color and a casual vibe. Large slip-covered sofas are paired with simple plywood tables in the living room, and arranged on a square flat-weave carpet. A bold racetrack dining table surrounded by casual canvas director’s chairs creates a simple and carefree dining area in the center of the room. These groupings mirror the symmetry and scale of the architecture while contributing to the relaxed feeling of a weekend retreat.

Environmental strategies

The home relies on both passive and active systems to control its thermal environment and tailor the demands to the occupancy of the space. Deep overhangs and strategic glazing provide natural shading and daylighting throughout the home. The slim volume of the home allows for extensive cross-ventilation with symmetrical openings on either side. Radiant heating takes advantage of the thermal mass of the concrete slab to warm the home in the winter time. A photovoltaic system onsite offsets the total electricity usage throughout the year for the property and supplies back-up batteries to keep the property operational in the event of an outage onsite, and, more importantly to power the fire sprinkler suppression system protecting the building should it be necessary. The site is off the grid in terms of sewer and water with its own dedicated well and septic thatare also backed up by the batteries.


The property’s grading, drainage and planting strategies maintain the original topography, prevent erosion and disperse rainwater in in-grade dissipation pits. Softscape and permeable surfaces were used wherever possible within the site design to allow rainwater and irrigation water reabsorption onsite. All irrigation is from an on-site well. The landscape, conceived by San Francisco based Surface Design, includes low-water native perennials – such as Deer Grass, Giant Chain Fern, Coffeeberry, Manzanita, Toyon – that are used throughout the property to create habitat for native birds and insects while minimizing water consumption. Four Buckeye trees – a keystone species for native butterflies and moths including the Pacific Azure and Orange Tortix Moth – were planted onsite with the construction of the main house.

In addition, in order to provide slope stabilization and nutrients to the rocky soil, native grasses and wildflowers were hydroseeded around the property.

Project name: Frame House in Sonoma
Project location: Sonoma County, California
Client: Private
Architect: Mork-Ulnes Architects –

Project consultants
Landscape architect: Surfacedesign, Inc. (Roderick Wyllie and Michal Kapitulnik)
Structural engineer: ZFA Structural Engineers (Kevin Zucco and Drew Fagent)
Interior Design: The Office of Charles De Lisle
Geotechnical Engineer: RGH Consultants (Jared Pratt)
Civil Engineer: Adobe Associates (Tim Schram)
Septic Engineer: Adobe Associates (Greg Schram)
General Contractor: Nordby Signature Homes
Lighting designer: Tucci Lighting

Project data
Site size: 18.43 acres (75,000 square meters)
Building footprint: 3,680 square feet (340 square meters)
Total conditioned area: 4,065 square feet (380 square meters)
Total cost: withheld

Photographs Bruce Damonte –

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