Wildfire-resistant construction costs are similar to typical costs

Camp Fire drone photo
Photo taken on the Camp Fire by a drone in Magalia, California near Indian Drive.

With tens of thousands of homes being destroyed in the last year in California wildfires it should be a very high priority for home builders and local governments to swiftly adopt the practices that can greatly reduce the vulnerability of structures. It is not a given that if a large rapidly-spreading wildfire approaches a house it will ignite and burn to the ground.

Media reports sometimes marvel at how an occasional structure will be spared, and may describe it as miraculous or random. Instead, it is based on science. Some structures are designed, built, and maintained to be less vulnerable than others. The other half of the equation is what is within the home ignition zone — what will become fuel within 100 feet. If there is continuous vegetation or other flammable material in that zone that can carry the fire, especially close to the structure, it stands less chance of survival.

But for now let’s think about the structure itself. There are several useful reference guides for architects, home builders, and zoning boards containing information that can lead to designs and building codes that can help keep a fire from turning into a disaster.

• International Code Council’s International Wildland Urban Interface Code (IWUIC),
• National Fire Protection Association’s Standard for Reducing Structure Ignition Hazards from Wildland Fire (Standard 1144), and
• California Building Code Chapter 7A—Materials and Construction Methods for Exterior Wildfire Exposure.

Headwaters Economics compared the costs of new construction of a typical home vs. one with wildfire resistant standards for a three-bedroom, 2,500-square-foot, single-story, single-family home representative of wildland-urban interface building styles in southwest Montana. Below are excerpts from the article:

compare costs wildfire resistant homes

We examined costs in four vulnerable components of the home: the roof (including gutters, vents, and eaves), exterior walls (including windows and doors), decks, and near-home landscaping. Overall, the wildfire-resistant construction cost 2% less than the typical construction, with the greatest cost savings resulting from using wildfire-resistant fiber cement siding on exterior walls, in lieu of typical cedar plank siding. While cedar plank siding is typical in the wildland-urban interface of western Montana, fiber cement siding is already a common choice in many regions because of its relative affordability, durability and low maintenance needs. Wildfire-resistant changes to the roof resulted in the largest cost increase, with a 27% increase in gutters, vents, and soffits. The following sections describe the wildfire-resistant mitigations for each component.

Some home insurance companies refusing to renew policies in wildfire-prone areas

Firewise defensible space structure

One of the most serious problems facing firefighters today is the movement of residents into the Wildland/Urban Interface, the WUI. As a wildfire spreads toward flammable structures that are near or in some cases surrounded by burnable vegetation it can be very difficult to protect them. Often as a fire grows in a WUI area containing dozens or hundreds of homes there are not enough firefighters to park a fire engine at every house.

Some structures are easier to protect than others. “Firewise” refers to homes that are designed and maintained to be fire resistant. A few burning embers (that can be transported in the wind for a mile) in most cases will not ignite a home built to withstand fire. It is the other homes, with flammable siding, roofs, and decks, and that have brush or trees providing an efficient path for the fire to spread up to the structure, that is a nightmare for the fire department. In some cases as a fire approaches, this second category of homes will be written off since it may not be possible to save them, even with a fire truck parked in the driveway. Without vegetation clearance of 30 to 100 feet, it can be unsafe for firefighters to remain at the site as an intense fire approaches.

Gunbarrel Fire
Firefighters at the Gunbarrel Fire west of Cody, WY apply foam and install sprinklers at Goff Creek Lodge, August 26, 2008. Photo by Michael Johnson.

A difficult to defend home is not only a problem for the owner, but it also affects the community. As it burns in a wildfire, it creates huge amounts of radiant and convective heat. Combined with the airborne burning embers put into the air as it burns, it can ignite other homes nearby. If multiple unprepared homes burn, the effects of the conflagration are multiplied making it difficult for even Firewise structures to survive. In addition, unprepared homes suck up more firefighting resources, which can make it difficult or impossible for there to be enough firefighters, crews, engines, and aircraft to suppress the wildland fire — they are often tied up because of some irresponsible residents.

In a perfect world all structures in a WUI would be Firewise. Inevitably, however, a sizeable percentage of homeowners will do nothing to make their structures defensible. There are two ways to encourage, or even force, them to take action before a fire strikes. Zoning laws and insurance companies. Laws can, for example, ban wood shingle roofs, and require vegetation clearances up to 100 feet, as well as other requirements. Many jurisdictions do this.

Insurance companies have an extremely powerful tool at their disposal that is rarely used. According to the NW News Network, at least two companies in Washington and Oregon are refusing to renew the policies for some home owners, or for structures in wildfire prone areas.

Below is an excerpt from NW News:

Some insurance companies are choosing not to renew policies in wildfire-prone areas of the inland Northwest. That’s sending home owners scrambling to find new coverage for their properties. Northwest-based insurers such as Pemco and Grange Insurance are getting choosier about how much risk they’ll take on. This according to property owners who’ve been dropped recently and posted about their frustrations online.

One customer from Chelan, Washington, complained Pemco refused to renew her homeowners insurance despite 17 years with no claims. The common thread among the non-renewals is location in wildfire country.

Oregon’s insurance regulators looked into this and said some insurers updated their wildfire risk rating models.

“There have been some non-renewals, rate increases, and moratoriums on new business, because updated risk models showed certain areas to be at especially high risk of wildfires,” wrote Jake Sunderland, a Department of Consumer and Business Services spokesman, in an email.

Refusing to write policies in a large area is not the best solution. Some companies will only insure structures after inspecting them to be sure they are Firewise and have defensible space.

First National Legacy Award presented to Forest Service retiree

Jack Cohan

Above: Dr. Jack Cohen makes a presentation at the 2011 Fire Litigation Conference in San Diego. Photo by Bill Gabbert.

Dr. Jack Cohen received the first National Legacy Award given by the U.S. Forest Service, National Association of State Foresters, National Fire Protection Association, and International Association of Fire Chiefs in recognition of outstanding career-long contributions to wildfire mitigation as an alternative to suppression. Dr. Cohen helped develop the U.S. National Fire Danger Rating System and developed calculations for wildland firefighters’ safe zones; created defensible space principles, which resulted in the Firewise program; the Home Ignition Zone; and conducted research on ember ignitions and structure ignitability.

His research laid the groundwork for nearly all of today’s work on wildland urban interface risk reduction. Until his 2016 retirement, he was a research scientist at Missoula Technology and Development Center. The award was presented at the IAFC WUI Conference in Reno, Nevada.

Thanks and a tip of the hat go out to Robert.
Typos or errors, report them HERE.

60 minutes: “Wildfires on the Rise”

EIler Fire Home

Above: One of the homes that survived the Eiler Fire in northern California, August, 2014. Photo by Bill Gabbert.

The CBS TV show 60 Minutes recently aired a story titled, “Wildfires on the rise due to drought and climate change“, concentrating on how to deal with the increasing number of wildfires, and particularly what homeowners can do to protect their investments.

Below is an excerpt from the transcript:

Events like [the Yarnell Hill Fire that killed 19 member of the Granite Mountain Hotshots] add urgency to the work at a U.S. Forest Service lab. In this building in Missoula, Montana, scientists study how fires spread.

And one of them, Jack Cohen, made a specialty of how to better defend homes.

Jack Cohen: Clearly we’re not gonna solve the problem by telling people they’re gonna have to move their houses into a city from being out in the woods.

Steve Inskeep: Not gonna happen.

Jack Cohen: Right? It’s not gonna happen for a whole bunch of reasons, one of which is that the population who live there, including me– aren’t gonna do it.

Steve Inskeep: Is it reasonable for a homeowner in that situation, a fire bearing down on their neighborhood to just say, “Look, I pay my taxes. There are firefighters, there’s a fire department. The forest service, if it’s public land, has thousands of firefighters. It’s their job; put it out?”

Jack Cohen: So what if they can’t? Then the question becomes one of, “Well, if the extreme wildfires are inevitable does that mean that wildland-urban fire disasters are inevitable?” And my answer to that is no.

Researchers study how the Fort McMurray fire ignited homes

screen-shot-2016-09-14-at-5-00-06-pmA preliminary report report released by the Institute for Catastrophic Loss Reduction looked at how the 1,500,000-acre Fort McMurray Fire ignited some of the 2,400 structures in the Alberta city in May of this year.

Below are excerpts from the document.

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After evaluating the fire environment and clearances between homes and the forest edge, the investigator discounted direct contact from flames or radiant heat of the forest fire as being significant sources of home ignition at Fort McMurray. Instead, it was concluded that wind-driven embers were the most probable cause for the majority of early home ignitions in the zone where the fire made its transition from forest into urban neighbourhoods. Once established, the fire would have spread from structure to structure as an urban conflagration, accounting for the majority of home losses.

home ignition zone
NFPA

In all neighbourhoods studied, homes whose owners had adopted FireSmart guidelines survived much more frequently than homes where they had not, despite the extraordinarily harsh conditions.

Recommended FireSmart guidelines work. They are effective in reducing the probability of home ignition and wildfire losses. Home survival does not appear to be random or a matter of luck.

Home survival depends on conditions in the home ignition zone, for which owners are responsible.

While low total hazard rating is important, a single critical weakness can lead to home loss.

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Articles on Wildfire Today tagged “Fort McMurrary Fire”.

President signs executive order to mitigate wildfire risks to Federal buildings

President Obama today signed an Executive Order on Wildland-Urban Interface Federal Risk Mitigation, intended to mitigate wildfire risks to Federal buildings located in the wildland-urban interface (WUI), reduce risks to people, and help minimize property loss to wildfire.

For new buildings and alterations to existing buildings greater than 5,000 square feet on Federal land within the WUI at moderate or greater risk to wildfire, the Executive Order directs Federal agencies to apply wildfire-resistant design provisions delineated in the 2015 edition of the International Wildland-Urban Interface Code promulgated by the International Code Council, or an equivalent code. These codes, which encompass the current understanding of wildfire hazard potential, will help increase safety and protect the lives of people who live or work in these buildings.