mork-ulnes architects tucks a 38 sqm guesthouse on a steep hillside in california

'we had to strive to make every square meter count and program almost every surface with some sort of function,' explains the architect.

lea zeitoun May 1, 2024 4 min

explore the Crest guesthouse by mork-ulnes architects

To create the Crest guesthouse and rental unit on a steep hillside property in Marin County, California, Mork-Ulnes Architects took the foundation from an old garage and built an Accessory Dwelling Unit (ADU) on its exact footprint. 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. Given the steepness and wooded context, the practice had to adhere to strict fire danger regulations. ‘Our aim was therefore to create a building that would be as fire resistant as possible given the tools and budget we had. This meant that there are no roof projections, the exterior cladding and roofing is cement board and the windows and doors had to be metal,’ Casper Mork-Ulnes tells designboom. Due to the incredibly steep hillside, a front deck is added to for more usable exterior space that takes advantage of the mild California climate.

mork-ulnes architects tucks a 38 sqm guesthouse on a steep hillside in california - 1 — Crest Guesthouse | all images © Bruce Damonte

a 38 square-meter and flexible programming

Designing for the utmost effective spatial layout, Mork-Ulnes deploys a 38 square-meter, flexible programming. ‘We had to strive to make every square meter count and program almost every surface with some sort of function,’ explains the architect. This gives the project an unsual twist, as the team needs to program all surfaces without taking attention away from standard architectural concerns like space and light. Mork-Ulnes describes this approach as a ‘Swiss-army knife functionality’. A rolling kitchen island can be moved in or outside when space or utility is needed, and a murphy bed hides in the wall during the day and folds down at night for sleeping. The loft space, with a window out towards the trees as well as down to the living space, is accessed by a ladder that tucks in to the wall. The bathroom is split into two smaller rooms – a toilet/sink and a forest-green tiled shower room with a glass door out to the tree covered hillside.

mork-ulnes architects tucks a 38 sqm guesthouse on a steep hillside in california - 2 — the rental unit sits on a steep hillside property in Marin County, California

Speaking of maintaining focus on space and light, the architect made sure that, despite its compact size, the Crest guesthouse still feels spacious enough for its guest by ‘allowing light to travel through the building to naturally illuminate the little house throughout the day. High clerestory windows facing the hillside while more large expansive sliding doors allow light to enter form the the deck, as well as extend the living area to the outdoors towards the view,’ concludes Casper Mork-Ulnes. The Crest Guesthouse is currently being used by the owners as their vacation cabin while their main house is being renovated.