In the serene landscapes of Marin County, California, the Crest Guesthouse stands as a stunning example of thoughtful architectural adaptation and innovative design. Conceived by Mork-Ulnes Architects, this project transforms the footprint of an old garage into a contemporary accessory dwelling unit (ADU) that embodies the essence of modern living and environmental sensitivity.
Crest Guesthouse Technical Information
- Architects1-6: Mork-Ulnes Architects
- Location: San Anselmo, Marin County, California, USA
- Topics: ADU
- Area: 411 ft2 | 38 m2
- Completion Year: 2023
- Photographs: © Bruce Damonte
To create a small guesthouse and rental unit on a steep hillside property in Marin County, CA, we took the foundation from an old garage and built a new Accessory Dwelling Unit on the exact footprint of the old garage. The building’s sharply angled roofline mirrors the slope of the site and gives a high clerestory window light above the cabinetry wall, while a playful flip in the roof provides a punched window from the loft viewing the trees
– Mork-Ulnes Architects
Crest Guesthouse Photographs
Innovation on Steep Slopes
The challenge was to create a small yet fully functional guesthouse on a steep hillside. The architects approached this by utilizing the existing foundation of the demolished garage, thereby minimizing land disturbance and integrating the structure seamlessly into the sloping terrain. The design leverages the steep gradient of the site, featuring a sharply angled roofline that not only complements the slope but also maximizes the internal volume of the building. This architectural choice is not merely aesthetic but functional, providing ample clerestory window light over the cabinetry wall and a distinctive punched window from the loft, framing picturesque views of the surrounding trees.
The exterior of the Crest Guesthouse is clad in fire-resistant cement board, a prudent choice considering the wooded setting. This material choice underscores a commitment to durability and low maintenance, essential qualities for structures in such environments. The addition of a front deck exploits the mild Californian climate, effectively doubling the usable outdoor space and enhancing the living experience by offering expansive views and a seamless indoor-outdoor transition.
Internally, the guesthouse is very efficient, covering just 411 square feet. The interior has a flexible design, featuring a rolling kitchen island that can be moved outdoors, a Murphy bed that folds away to free up space, and a loft accessed by a cleverly concealed ladder. These elements allow the dwelling to remain uncluttered and spacious, despite its compact footprint. The split bathroom design—with a separate toilet and a forest-green tiled shower room—adds a touch of luxury and practicality, further emphasized by the direct access to nature through a glass door.
Sustainability is at the heart of the Crest Guesthouse, reflected in its use of energy-efficient materials and systems like the Lunos decentralized HRV system for ventilation. The building’s materials were chosen not only for aesthetic quality but also for their environmental credentials, including weather-resistant barriers and vapor retarders to enhance the building’s energy efficiency.
The Crest Guesthouse by Mork-Ulnes Architects is more than a home—it is a demonstration of how modern living can be achieved in harmony with nature, pushing the boundaries of design and functionality in one of the most picturesque settings in California.
Crest Guesthouse Plans
Crest Guesthouse Image Gallery
About Mork-Ulnes Architects
Mork-Ulnes Architects, a firm with offices in San Francisco and Oslo, is known for its unique fusion of Scandinavian practicality and Northern California’s innovative spirit. Founded by Casper Mork-Ulnes, the practice is acclaimed for its rigorous, concept-driven approach that spans a diverse portfolio from tiny cabins to large-scale masterplans across three continents.
Notes & Additional Credits
- Design Team: Casper Mork-Ulnes, Phi Van Phan, Robert Scott, Lexie Mork-Ulnes, Kaoru Lovett
- Job Captain: Kaoru Lovett
- Structural Engineering: David Strandberg
- Civil Engineering: Adobe Associates, Inc. (Aaron R. Smith)
- General Contractor: Damner Construction, Axelson Builders
- Communication Partner: The Architecture Curator
