3 Ways to Make Your Home More Fire-Resilient

Whether you are rebuilding after a wildfire or simply looking to make an existing home more resilient, there are several design decisions that can significantly reduce a building’s vulnerability to fire.

For homeowners in wildfire-prone areas such as the Pacific Palisades, Altadena, and other parts of Southern California, fire resilience is increasingly becoming a central part of residential design. Material selection, ventilation, glazing, and even the framing system itself can all affect how a home performs during a wildfire. Here are three strategies we are currently incorporating into fire-resilient residential projects.

1. Eliminate Combustible Materials From the Building Envelope

One of the most important steps in designing a fire-resilient home is reducing the amount of combustible material on the exterior of the building. Painted wood shiplap and board-and-batten siding are common on traditional homes, but wood siding can ignite when exposed to sustained flames or intense radiant heat. Even durable hardwoods such as Ipe will char and burn under prolonged fire exposure. There are a number of noncombustible or highly fire-resistant alternatives that can achieve a similar architectural character, including:

• Fiber-cement siding

• Steel panels

• Aluminum siding

• Stucco

• Stone

• Brick

Fire resilience also does not mean that a home has to look industrial. On a fire-rebuild project we are currently designing in the Pacific Palisades, for example, we are using a printed aluminum siding product that closely replicates the appearance of natural wood. From only a few feet away, it can be difficult to distinguish from the real material.

We are also incorporating U-Stucco, a high-performance exterior plaster system that has been tested in assemblies subjected to extremely high temperatures for extended periods.

Windows deserve similar attention. Wood window frames introduce another combustible element into the exterior envelope, but the glazing assembly itself is equally important. During a wildfire, radiant heat and direct flame exposure can cause glass to fail, creating an opening through which flames and embers can enter the building. For this reason, fire-resilient homes should consider aluminum, fiberglass, or steel window frames combined with dual-pane assemblies and tempered glazing.

2. Install Ember-Resistant Baffled Vents

Wildfires do not spread only through direct flame contact. Wind-driven embers can travel long distances ahead of the main fire front and are responsible for a substantial percentage of home ignitions in Wildland-Urban Interface areas. These embers can enter a home through attic vents, crawlspace vents, roof openings, and other small gaps in the building envelope. Once inside a wall or attic cavity, an ember can smolder for a long period of time before visible smoke or flames appear. Conventional attic and crawlspace vents are often protected by only a single layer of mesh. While this screen may prevent larger debris or pests from entering the building, small embers can still pass through.

Ember-resistant vents are designed differently. Many use a combination of multiple layers of metal mesh, internal baffles, or other tortuous pathways that make it much more difficult for burning embers to pass directly into the building. Some systems also incorporate intumescent materials that expand when exposed to high temperatures, helping close off the vent during extreme heat conditions. Because vents are necessary for many conventional roof and crawlspace assemblies, improving their resistance to ember intrusion can be one of the most important details in a wildfire-conscious building envelope.

3. Consider Light-Gauge Steel Framing

For homeowners rebuilding from the ground up, the structure itself presents another opportunity to improve fire resilience. Most homes in Southern California are framed with wood. While wood framing is familiar, economical, and widely available, it also provides additional combustible material once fire enters the building envelope. Light-gauge steel framing offers a different approach. We recently toured a light-gauge-steel home in Altadena that survived the Eaton Fire. Portions of the home were exposed to fire, including areas where the roof assembly was burning, but the steel framing did not contribute additional fuel to the fire. Steel is noncombustible, dimensionally stable, and well suited to highly precise digital fabrication. Our architecture firm has been designing homes with light-gauge steel for nearly ten years, and automated steel framing has become one of our specialties. With modern automated fabrication systems, an architect’s digital building model can be translated directly into fabrication information for a roll-forming machine. The framing members are then produced to the exact dimensions required for the project. This process can improve precision while also reducing the amount of combustible structural material within the building.

Fire Resilience Is a System, Not a Single Product

There is no single material or technology that can make a home completely fireproof.

Instead, wildfire resilience comes from combining multiple strategies: noncombustible exterior materials, ember-resistant vents, resilient glazing, careful detailing, defensible space, and thoughtful structural systems. The goal is not to design a bunker.

It is to design a home that is beautiful, comfortable, and appropriate to its architectural context while also reducing the number of ways that fire and embers can ignite the building.

For homeowners rebuilding in the Pacific Palisades, Altadena, or elsewhere in Southern California, the rebuilding process presents a rare opportunity to reconsider how a home is designed and constructed. If you lost a home in the recent fires or are considering a fire-resilient new home, Form Found Design would be happy to discuss your project and the strategies that may be appropriate for your site.