Lichen House

The Lichen House is nestled among the fog and oaks in the hills above Sonoma Valley. The branches of the site’s trees support veils of draping Ramalina Lichen that filter sunlight, capture moisture and nutrients for their host oaks, and remove pollutants from the air.  A hypersensitive organism, Lichen retreats or dies in adverse or contaminated environments but quickly expands its net with advantageous conditions.  It is a bellwether for the environmental health of this unique microclimate. The precise symbiotic relationship between lichen and their host environment provides inspiration for an architecture specifically tailored to its site — both as a response to it and an expansion of its best attributes.

 

The site’s prevalent lichen communities establish an ethos of fostering symbiotic, rather than dominant, relationships between the built and unbuilt worlds.  The lichen’s ability to freely seek out and extend its net towards sustainable conditions also inspires a fluidity of movement and gesture in the architecture.  We harness this opportunistic mindset to allow the building form to find its shape. In the heat of the day we gravitate towards the filtered light of the oaks; in the foggy mornings and breezy evenings we extend toward the clearings and views. At the entry driveway and edges of the site the structure shields specific views. The home’s ends pull toward long expansive views to the south and west with the freedom to precisely dial in orientation to focal points in the landscape.  The form bisects at the natural entry point revealing views to Sonoma Mountain and dividing the house into public and private zones.

 

The divided plan is connected via a circulation spine along the inner edges.  Each room is carefully tuned to its own spatial “microclimate” considering, privacy, views, solar orientation, quality of light, and air flow.   A series of gardens and open spaces work in concert with each zone of the house interior. A kitchen garden utilizes the sunny edge of the site and helps screen the neighboring property. A shady play courtyard and dog run lines the northern bedrooms while a more natural southern garden is filled with the dappled light of the trellis “net” above.  The master suite is centered on a protected spa-like courtyard that brings the landscape directly into the home.

 

Rather than battle against the perceived heaviness and thickness in the roof as many Modernist buildings do, here we work in concert with the needs of structure and water flow to define the roof topography. The frayed and porous edges of the roof are filled with undulating metal fins: both a formal reference to the surrounding lichen’s geometry as well as a spatial reference to it –recreating the dappled light of the lace lichen’s net.

The Lichen House works in concert with nature’s mechanisms, not to mimic them blindly, but to expand our understanding and experience of them through architecture.

Design Challenge

In order to take advantage of the site’s position on the lush hillside, a goal of the project was to maximize the dramatic views of the valley and surrounding landscape from the house. Due to the nature and orientation of the site, the best views were towards the west and south, creating a solar heat and exposure challenge that would need to be integrated in the design of the house.   We developed a shading trellis on the southern edges of the roof, strategically positioned to filter the high summer sun while allowing heat gain in the winter when the sun is lower in the sky. Inspired by the breathable filter of the lichen's net, the trellis mitigates the exterior effects on the south-facing space with a series of operable windows along the private wing of the home. A series of undulating metal fins fill the trellis surface, acting as both a formal reference to the surrounding lichen’s geometry as well as a spatial reference by recreating the filtered dappled light of the lace lichen’s net.   Integral to the design of the trellis, the regular pattern of aluminum fins use the natural flexibility of the material to introduce a series of snap-rivet connections that create the undulating lichen pattern.  Trellis sections were laid out precisely for the fabricator; while appearing highly complex, each section was based on a simple geometric system.  While the pattern of rivet connections stayed constant, the overall frame shape varied, thus compressing and expanding the density of the pattern along its length.   The trellis detail highlighted again for us the collaborative spirit of architectural design.  At first, the fins were imagined as rebar sections (client rejected), then concrete board (contractor rejected), then steel (budget rejected) until finally aluminum held sway.  To test its effectiveness we created a full-scale mock-up.  Once the sun came around and the shadows began to play, the team knew we had hit our target; creating something that referenced nature but also expanded upon it. Not only did the trellis mitigate and filter the effects of the sun in order to meet the needs of the south-facing facade, but it also created an opportunity to study and design an innovative way to do so that harnessed the spirit of the project.

Physical Context

The precise symbiotic relationship between species of lichen on the site and their host environment provides inspiration for an architecture specifically tailored to its site -- both as a response to it and an expansion of its best attributes. The lichen’s ability to freely seek out and extend its net towards sustainable conditions also inspires a fluidity of movement and gesture in the architecture. We harness this opportunistic mindset to allow the building form to find its geometric shape.   Beginning with the strategic solar orientation and geometry, the Lichen House owes its form to passive thermal tactics ‐ the maximization of daylight and expansive southern views protected by a deep overhanging shade trellis. The lichen trellis filters the high summer sun and allows solar heat gain in the winter when the sun is low in the sky. Inspired by the breathable filter of the lichen's net, a south facing unconditioned hallway space with a series of operable windows along the private wing of the home serves as an interstitial buffer zone. This buffer zone simultaneously protects the sleeping quarters from direct southern exposure, dampening heat loss and heat gain while also promoting natural airflow‐effectively minimizing the conditioned floor area and required heating/cooling loads of the house. Similarly, the roof itself acts as a protective buffer zone. Taking its formal cues from the slopes required to direct the flow of rainwater run‐off, the resultant roof form of low sloping ridges and valleys is vented though the fascia, pulling heated air out through the attic cavity. The cushion of cooled air within the attic buffers and protects the conditioned spaces of the home below.   The home’s ends pull toward long expansive views to the south and west with the freedom to precisely dial in orientation to focal points in the landscape. Each room is then carefully tuned to its own spatial “microclimate” considering, privacy, views, solar orientation, quality of light, and air flow. A series of gardens and open spaces work in concert with each zone of the house interior. The roof’s southern edges are filled with a series of undulating metal fins, which are both a formal reference to the surrounding lichen’s geometry as well as a spatial reference by recreating the filtered dappled light of the lace lichen’s net.