BUILDING RESILIENCE:
Fire-Resistant Strategies for Modern Home Construction
BUILDING ENVELOPE
HYBRID HOUSE
FIRE-RESISTANT HOMES
More on why fire-resistant homes should prevent overhangs and eaves:
Fire-resistant construction begins with the components of the building envelope; the wrapper of the structure. Building envelopes have to resist primary effects of an advancing brush fire. As the fire approaches a structure, it seeks the lowest elements first, and any overhangs or discontinuities (however slight) in the plane of the house. Keep vents & openings to a minimum as these will collect embers.
This is also true of airborne embers which can land on facade projections and smolder and ignite. Therefore, facades should be kept clean and smooth where possible. Eaves are another critical weak spot which can make it easier for a fire to ignite a structure; capturing rising heat & flames.
Vegetation management: A plant-free perimeter of 5 feet should be set up around the house, with non-combustible materials such as stone, gravel and dirt instead of wood mulch type substances that can smolder. This holistic approach will unify landscaping with the defensible space.
MATERIALS
University of California has provided a wildfire mitigation guide on building materials:
https://anrcatalog.ucanr.edu/pdf/8393.pdf
https://wfca.com/wildfire-articles/top-fire-resistant-materials/
The best material options are metal, concrete (both non-combustible) and class-A fire-resistant siding.
Traditional wood siding, shingles & panels are unacceptable in a fire-safe home.
Metal panels come in formed sheets and flat panels, providing excellent protection from ground fires. These sheetmetal options are pre-finished and easy to install, often used in commercial structures.
Glazing: two layers of tempered/ laminated glazing is recommended.
Concrete panels = sheets and precast ‘tiles’. These provide excellent protection from laterally advancing ground fires and ember casting. Fiber cement panels, a composite of cement and admixtures, are also an excellent option for fire-resistant construction.
Some synthetic composite siding options provide wood-look elements with an ASTM class A fire rating, the highest rating provided by the National Fire Protection Association. These combine superior fire resistance with the appearance of true wood cladding, when exposure to adjacent combustibles is limited. One such product is a composite of rice husks, common salt and mineral oil.
STRUCTURE
Learn how steel structure can achieve high design in a fire prevention conscious manner:
The final line of defense against a residential fire is the structure itself. The wall framing & major structural elements (beams & columns) can save a structure if they, too, are non-combustible. Though not common in residential construction, metal building shells (beams, columns & wall framing) will not burn.
This option is surprisingly affordable, and can be beautiful, practical and economical.
Pre-Engineered Metal Buildings are shipped to the site, ready to assemble, for much less than the cost of traditional framing. Their frames bolt together on site quickly, and save on time & labor costs.
When exposed inside, the steel elements can be stunning, adding a rhythm to the space and a dynamic sense of structure.
A steel structure can also reach interior heights that are much more difficult for traditional framing systems. All for a fraction of the cost of standard framing.
LOOKING FORWARD
"A great misconception is that regular houses cannot survive wild fires because of scope and intensity, but properly designed buildings can indeed weather the challenges."
~ NATHAN WITTASEK
Fire Protection Engineer & Fire Investigator
Simpson, Gumpertz & Heger
In sum, halting the process of a rapidly approaching fire is a difficult task. Often it is impossible. And another fire in this climate and this region is surely inevitable. But intelligent design choices and materials specifications can greatly reduce the flammability of a structure and greatly increase the chances that it will survive. This paper outlines some of those design strategies and materials selections in the hope that more structures can survive the next fire.
RESOURCES
Further resources to learn more about fire safety strategies and how you can help:
CALFIRE:
https://readyforwildfire.org/wp-content/uploads/2024/05/Low-Cost-Retrofit-List-Updated-5_1_2024.pdf
https://readyforwildfire.org/prepare-for-wildfire/
University of California:
https://ucanr.edu/sites/Wildfire/Links/
California Fire Safe Council:
https://cafiresafecouncil.org/
Webinar by the Coalition for Clean Air:
https://www.ccair.org/wildfire-and-smoke-safety-resources/
Standards and Updates:
https://ibhs.org/risk-research/wildfire/
https://laist.com/news/climate-environment/how-to-help-la-fire-victims
https://laist.com/news/climate-environment/los-angeles-fires-faqs-laist
