SANTA ROSA (KPIX) — Seven months after the devastating wine country wildfires in Napa and Sonoma counties, homeowners who lost everything are starting to rebuild. Some are turning to a newer type of construction that’s been billed as better at withstanding disasters. It’s called ICF – Insulated Concrete Forms – a construction method that’s been around for more than 50 years, and more commonly found in hurricane and typhoon-prone areas.
Santa Rosa resident Rene Latosa first heard about ICF several months ago after the Tubbs fire destroyed his home in the Fountaingrove neighborhood. After talking to an ICF builder, and viewing an ICF home, he’s convinced that’s what he wants for his replacement house. “The fire safety is almost 100%, the durability is 1,000 years, so they say,” said Latosa.
The claims are impressive. ICF has been billed in advertisements and articles as “virtually indestructible,” “able to withstand winds of up to 250 miles per hour,” and “fireproof.”
More than 20 companies manufacture ICF systems, and each has its own proprietary formula. But the basic method is the same: Hollow blocks of fire-resistant foam that are fitted with rebar, are stacked to form walls. They’re then filled with concrete and covered with siding. Builders then add roofs, floors, windows and other components to finish the house.
Latosa’s builder, Nicholas Nikiforuk is currently constructing an ICF home in Saint Helena that will have also have a concrete roof, and concrete floor, and other enhancements, that he says will enable it to survive the worst disasters. “It’s going to last forever,” said Nikiforuk. “It’s earthquake proof, tornado proof, hurricane proof, tsunami proof, mudslide proof, every sustainable disaster.”
Nikiforuk said that list also includes wildfires, like the 2,000+ degree inferno that roared through wine country back in October. It “will never burn,” he said.
But some question the claims that ICF homes are fireproof. “That’s not a legal term,” said Dana Buntrock, University of California architecture professor and architect. Buntrock says home construction materials are rated by the number of hours they will resist a fire and allow people inside to escape safely. While most construction materials are rated one or two, concrete is rated three or four. If ICF’s are only used for the walls – which Buntrock says is usually the case – that could mean other parts of the home, like roofs, windows, and doors are vulnerable.
“If you’ve got a gap where a fire can get in, and your finishes are flammable inside, and they probably are, that’s stuff’s still flammable,” said Buntrock. Wind-blown embers are blamed for spreading the North Bay wildfires to many homes.
David Horobin, a partner at Estudio Verde Architects in Napa, is careful not call ICF homes fireproof. “I’m encouraging people to call it highly fire-resistant, which it is,” said Horobin. “If for some reason the house were to burn from the inside, there would be problems.”
Or, if someone left windows open and a fire roared past, the home could burn from the inside. But Horobin contends that when made with equally protective components, ICF homes are very strong. “We can combine all these materials to make an entire building envelope that’s as fire resistant as possible,” he said.
A home in Santa Rosa with ICF walls did burn in the October firestorm. The home was built in 2010. The owner told KPIX 5 the concrete was degraded to the point that it could not be reused.
At least one ICF home builder says some builders may be going too far, trying to create an all-concrete house. “To me a concrete roof is foolish. They’re swinging the pendulum too far,” said Chip Gauthier, a general building contractor who has built two ICF homes in Grass Valley. Gauthier says metal, composite shingle or tile roofs that are fire-rated are effective and produce the best return on an investment. He also says gutter guards (now required by the state of California for new home construction) and special exterior paints can also increase fire resistance.
“People are getting too fanatical about this,” said Gauthier. “Just do some common sense things.” He also advises using a siding like stucco, cement, or metal, not wood shingles.
Proponents of ICF say it has other benefits besides durability. Horobin says they’re much more energy efficient than wood frame homes, because the concrete regulates the homes’ temperature. “Your energy bills will be the thing that pays for it many, many years in the future,” said Horobin. In addition, ICF homes absorb sound, so the homes are quieter. “Very little outside sound gets through,” said Horobin.
Many ICF builders also claim lower insurance costs. People with ICF homes could see a 40% reduction in their insurance, according to Nikiforuk. However, Janet Ruiz of the Insurance Information Institute cautions, “You might get a discount.”
Ruiz says insurance rates are based on a variety of factors and advises people considering ICF to call their insurer directly to see ICF construction is considered a factor when determining rates.
Unbiased information about ICF homes is hard to find. The Insurance Institute for Business & Home Safety (IBHS), a non-profit concerned with sustainability and resiliency, says it hasn’t studied ICF specificially. An IBHS spokeswoman told KPIX 5 that ICF is considered one component of a home. To be protective against fire, “the whole house has to be built as a system.”
Underwriters Laboratories, an independent safety and consulting company, also said it could not provide information about ICF.
What about costs? Horobin says ICF walls typically cost 3 to 5% more than standard walls. That’s $20,000 for a $500,000 house. But many other factors determine home building costs including home location, labor availability, finishes and the myriad details that go into completing the structure.
Adding more concrete will add to the price, said Buntrock. Finding laborers skilled in ICF could also be an issue. “There are not a lot of people that know how to do it,” said Buntrock. “There are tricky things about it.”
But Buntrock says it’s no surprise interest in ICF is increasing. “I think it’s understandable that people would feel like concrete might be safer,” she said. But she claims they may not actually be safer than in a well-constructed home made of other high-rated fire resistant materials. “The extra cost of the concrete isn’t going to get you anywhere,” said Buntrock.
LaTosa is hoping for the best result for his rebuilt home in Santa Rosa’s Fountaingrove neighborhood. After his ICF home is completed, LaTosa said he never wants to rebuild again. “I might pay a little more, but I think it’s worth it.”