U.S. Building of the Week

Ridge House

Mork Ulnes Architects
7. October 2019
Photo: Bruce Damonte

Three staggered concrete volumes follow the gentle slope of a property in Sonoma, California, their roofs lifting up to views of the sky and a canyon. The guesthouse, designed by Mork Ulnes Architects, is also a sturdy house that was put through a test last year. Casper Mork Ulnes explained by answering a few questions.

Project: Ridge House, 2018
Location: Sonoma, California, USA 
Client: Withheld 
Architect: Mork Ulnes Architects 
  • Design Principal: Casper Mork-Ulnes 
  • Project Manager: Alicia Hergenroeder 
  • Project Team: Greg Ladigin, Lexie Mork-Ulnes, Kyle Anderson, Erling Berg, Phi Phan, Signe Madsen, Simon Reseke, Monika Lipinska, Kristina Line  
Structural Engineer: ZFA Structural Engineers 
MEP/FP Engineer: Interface Engineering 
Landscape Architect: Surface Design 
Lighting Designer: Revolver Design 
Interior Designer: The Office of Charles de Lisle 
Contractor: Nordby Signature Homes 
Concrete Supplier: Partners Contracting, Inc. 
Site Area: 18.43 acres 
Building Area: 1,400 sf (840 sf conditioned)
Photo: Bruce Damonte
What were the circumstances of receiving the commission for this project?

We had previously designed an extensive remodel for a house in Sonoma. When the house was sold, the new owners enlisted us to design a pool and a guest house.

Photo: Bruce Damonte
Please provide an overview of the project.

In this compact Sonoma guesthouse, three board-formed concrete sculpted volumes carve into dry earth, suspending guest rooms over a plateau’s edge. The building is composed of three small volumes that step down with the changing grade, nesting into the site’s natural contours so that the mass of the building is softened into the hillside. Concrete blends with the rich, rusty colorations of the property’s rock, warmer concrete retaining walls, and a dynamic landscaped setting to enhance the impression of its rootedness. A continuous, multi-gabled roof joins the private units into a coherent whole. Solid concrete walls and roof shield the interior from the sun during the harshest times of day. The roof’s oblique ridges direct views from within the house out to the remarkable hills beyond and shade the windows to protect from the intensity of the summer sun.

Photo: Bruce Damonte
What are the main ideas and inspirations influencing the design of the building?

Views, the natural landscape, and topography were the design drivers for the project.

How does the design respond to the unique qualities of the site?

While the project is firmly rooted on the entrance side of the building, it perches on the ledge of the ridge and reaches outwards towards the canyon and sky on the view side. The guesthouse’s siting, form, and materiality craft dramatic – yet peaceful spaces within the three concrete volumes to give private access to the view.

Photo: Bruce Damonte
How did the project change between the initial design stage and the completion of the building?

The initial concept of the building did not greatly change, with the exception of structural design that developed through the detail design phases through collaboration with the structural engineer and contractors. This affected the way the buildings meet the ground plane.

Photo: Bruce Damonte
Was the project influenced by any trends in energy-conservation, construction, or design?

We see a turn to simplicity and a desire for serene environments from clients who come to us seeking a refuge from daily life. With that in mind, we attempted to keep the materials and color palette to a bare minimum so that the focus of the guesthouses was a serene place to enjoy the views of the canyon and the peacefulness of the environs. With regards to energy conservation, radiant heating and cooling were deployed in addition to utilizing the thermal mass of concrete.

Photo: Bruce Damonte
What products or materials have contributed to the success of the completed building?

As the project was almost entirely built of concrete – chosen for its permanence and fire resistant qualities – the project was literally tested with the Sonoma County wildfires of 2018.

Email interview conducted by John Hill.

Photo: Bruce Damonte
Photo: Bruce Damonte
Photo: Bruce Damonte
Site Plan (Drawing: Mork Ulnes Architects)
Floor Plan (Drawing: Mork Ulnes Architects)
East Elevation (Drawing: Mork Ulnes Architects)
North Elevation (Drawing: Mork Ulnes Architects)
South Elevation (Drawing: Mork Ulnes Architects)
West Elevation (Drawing: Mork Ulnes Architects)

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