Written by Bryn Garrett
Across the United States, and especially along the west coast in California, Oregon, and Washington, wildfires pose a real threat to life and property. According to the National Fire Protection Association (NFPA), more than 25,000 structures were lost to wildfires in 2018 alone, over 18,000 of which were residential properties. Clearly, many homeowners want to take whatever steps possible to decrease the risk that these fires pose to their homes.
While it may not be possible to build a fireproof home, there are a number of factors that can help to make your home more resistant and protected from the threat of wildfires. Below, we discuss these factors so that you can make more informed decisions in designing and building your home.
Design Considerations for Fire Resistant Residential Design
1. Site Selection
Where you choose to build your home is one of the most important factors that will determine how susceptible the home will be to wildfires. This is due to the fact that certain areas—especially undeveloped areas or those adjacent to them—are simply at a greater risk than others.
As it relates to fire resiliency, these sites typically fall into three categories: Greenfield, Brownfield/Urban Infill or WUI. Greenfield sites are those that have not been developed previously; they have been left to nature, and are often overgrown with plantlife which can become combustible during periods of drought. Brownfield of Urban Infill sites are previously developed lots often with utilities, and adjacent to other developed areas (whether dense or not). Wildlife-Urban Interface (WUI) Zones, on the other hand, are not undeveloped, but they are adjacent to those undeveloped areas.
In most cases we recommend that our clients should consider the benefits of building in an already developed site or a brownfield site, whether in an urban environment or in a less densely populated suburban lot. We prefer to be involved early in the process with our clients, where we can help to evaluate sites and explain the pros and cons of different properties they are evaluating early on in the process. While fire resistance is not the only concern, it is something that should be seriously considered, especially given the recent events in California.
If you do choose to build in a WUI zone, it’s important to understand the risks involved, as well as the specific regulations that you will need to meet that are enforced by the state of California. While this list is extensive, one example is roofing. If you choose to build in a WUI, your roof would need to be built to be fire resistant, leveraging construction techniques, design, and materials which would lower the chances of a stray ember igniting the structure.
2. Fire Resistant Building Materials
Naturally, the materials that you use to build your home will also play a role in determining how susceptible it is to combustion. Some materials, such as stone, concrete, and masonry are naturally non-combustible, and lend themselves really well to a modern design. Of course, other materials, such as wood, are more combustible. Leveraging the right materials for the right uses and in the right parts of your home can go far in reducing your fire risk.
If you are set on including wood in your design, the good news is that there are a number of options that you can use which will still reduce your susceptibility to fire damage. Shou sugi ban, for example, is a charred black wood that is common in Japan. In addition to being visually compelling, shou sugi ban is naturally fire resistant due to the fact that the outermost layer of the wood has already been charred.
Additionally, there are many products on the market that consist of wood which has been impregnated with a resin material to make it non-combustible, and these sorts of wood are an acceptable building material in many WUI zones. When we use materials which have been treated in this way, we always lean towards materials which have been created with sustainability in mind. Though fire resistance is important, it’s also important that the chemicals used to treat the wood will not be toxic to the environment in the event that it does burn.
3. Fire Resistant Landscaping
In addition to being something that is beautiful and that is meant to be enjoyed on a daily basis, intelligent landscaping plays a very important role in protecting the home from the threat of wildfire.
Everything from the layout of a yard or site to the variety of plants leveraged throughout the yard to the upkeep and maintenance of those plants can contribute to making a home more or less susceptible to fire, so it’s a crucial piece of the puzzle to get right. As just one example, consider that a eucalyptus tree can quite literally explode if it ignites, due to the oils and gases that the plant produces. This, paired with the fact that the plant is an invasive species, will often lead us to recommend that they be removed from a site.
One of the most important things that we consider early in the process of designing the home and the landscaping is the concept of creating what is known as a defensible space. This is the clearing between the home and the combustible material in the landscape. Fire needs fuel to grow and spread, so by removing this fuel around the home, it becomes more difficult for the fire to reach the structure.
This is why you’ll often see structures like decks, pergolas, patios, and other hardscape near the home, while the landscape itself is pushed further away. The goal is to create that protective barrier of empty space. Collaborating with landscape architects, who really are at the forefront of landscape design in fire prone areas, can be extremely beneficial in this respect.
Protecting Against a Known Threat
Across the western United States, and especially in California, wildfires are a real and present threat—and one that climate change is making more common. While it is impossible to build a home that is truly fireproof, taking the appropriate steps now to make your home more fire resilient is simply the smart thing to do. Everything from location to building materials to landscape can be leveraged to decrease the risk that fires pose to your home, so it’s important that you consider them.
