Decentralized urbanization coupled with a growing demand for housing in California has led to the creation of Wildland Urban Interface (WUI) zones, where suburban and low-density housing intermingle with undeveloped, vegetated lands. It is in these zones that wildfires cause massive property loss and result in the disintegration of entire communities.
As housing communities grow and expand into undeveloped areas, they perpetuate high-risk conditions that leave homes prone to inevitable wildfire damage. These conditions include building homes in densely vegetated areas which border on wild forests, and building homes in close proximity to each other - enabling a fire to easily jump from one structure to the next. After fires consume entire neighborhoods, the majority of residents are unable to rebuild homes on their existing foundations, forcing them to move elsewhere, leaving ghost towns in their wake.
We propose a WUI-specific housing typology, which allows evacuated residents to return to their homes after a fire has been neutralized and contained, without having to rebuild their entire home from the ground up.
This proposed typology divides the home into two separate buildings that share a common wall: the Bunker and the Pavilion. While the Bunker is a fixed design with a rigid shell, the Pavilion, constructed from pre-fabricated cold-formed steel framing, can be tailored and customized by its residents to create unique and open living spaces, using a modular system of 5-foot by 5-foot bays.
The prototype demonstrated here includes a Bunker with 4 bedrooms, a detached garage, and a pool. The Pavilion extends off of the kitchen and has a raised flat roof that glides over the Bunker. At the kitchen, the Bunker and Pavilion share a common wall, which has an opening that allows the kitchen and dining areas to be connected. An operable fiber cement panel closes off the kitchen, keeping the Bunker sealed and protected even if a fire managed to penetrate the Pavilion.
The Bunker houses the sleeping, bathing and kitchen areas, as well as essential infrastructure like mechanical equipment, electrical panels and plumbing mains, contained in a utility room off of the kitchen. Its shell is constructed entirely of non-combustible materials: exterior walls of autoclaved aerated CMU are clad in fiber cement panels and roofed with concrete T-beams. Openings are kept to a minimum and armed with a system of roll-down fire shutters and moveable fiber cement panels.
The PAVILION houses open living spaces, in a prefabricated cold-formed steel structure clad in fiber cement panels and infilled with tempered glazing units. This steel structure is strengthened by braced walls using cables, which are clad in fiber cement panels at the perimeter but left open and unfinished at the interior - allowing visibility through the length of the space. The light-filled openness of the PAVILION stands in stark contrast to the protective nature of the BUNKER.
The non-combustible cladding and tempered fenestration of the BUNKER+PAVILION conform to WUI code requirements. When the residents evacuate, the BUNKER can be completely sealed to protect the home’s valuable infrastructure. While the BUNKER will withstand a major firestorm, the PAVILION will likely require rebuilding, and the BUNKER will provide residents with temporary housing during that process.