Placer County contractor build its first concrete home in Santa Rosa-area fire zone

From the sidewalk on Willow Green Place, Bill Fredrickson and Michael Russo’s new house looks like a concrete replica of the wooden frame houses on the block destroyed by the Tubbs fire two years ago.

Like the other homes, it’s got multiple gable walls, eaves with pronounced overhangs and steep, pitched roofs - but all these features are made of poured concrete.

When all the stucco and ornamental detail are put in place, you won’t be able to tell the difference, Fredrickson said. Using concrete to rebuild instead of wood was a no-brainer, he said.

“Who in their right mind would build a wood house in a wildfire area, if you could build the same house for the same budget?” Fredrickson said.

Fredrickson and Russo’s home, one of the 5,300 Sonoma County homes destroyed in the October 2017 wildfires, is located off Old Redwood Highway just south of the Larkfield-Wikiup burn zone. The destructive force of the Tubbs inferno left no question in Fredrickson’s mind how he and his husband would rebuild.

“I wanted to rebuild it in concrete the second I knew it was available,” Fredrickson said.

Despite its fire-resistant qualities, there are only a handful of concrete homes being built in Sonoma County. Greg McDonagh, the contractor building the Willow Green Place home, hopes to change that. McDonagh, president of Roseville-based Savior Structures, said the high cost of traditional wooden frame construction now has made homebuilding with concrete a more viable option.

McDonagh, who entered the construction business straight out of high school, has been building residential and light commercial structures for 40 years. In late 2006, he invented a concrete wall-forming ?system using special separators to create narrow plywood boxes for pouring concrete.

Within Santa Rosa city limits, there are only four or five fully concrete homes built since the fires, said Jesse Oswald, the city’s chief building official. Tennis Wick, director of Sonoma County’s permit and resource management department, said Savior’s project is the only concrete home proposed, permitted and constructed in burn zones in unincorporated areas of the county.

Another concrete building technique that’s been used in Fountaingrove homes involves the use of insulated concrete forms, which use a permanent mold for poured concrete. The method produces a single-cast reinforced concrete structure that is also fire-resistant, and the polystyrene mold remains a permanent part of the home.

With McDonagh’s concrete system, the plywood forms or boxes are removed leaving only the concrete, the special separators and reinforced rebar. Expanded polystyrene foam board is inserted into the plywood boxes for insulation.

McDonagh, who was working in Utah in 2006, developed his Spider Tie separator system to build basement walls and not have to rely on concrete contractors. Two years after he devised his concrete building technique, the U.S. economy crashed and the bottom fell out of the homebuilding industry.

McDonagh, whose concrete forming system was already being used by pool builders, turned to designing and constructing city pools, aquatic parks and water tanks. The versatility allowed for the design of unique concrete designs and extreme curves.

“We learned that we could build a concrete structural pool for the same, if not less money, than gunite,” McDonagh said. “The versatility in forming shapes is where we really shine. We had a motto: ‘No one bends concrete like we do.’?”

In 2012, as the economy improved, McDonagh returned to homebuilding, taking what he learned from pool and aquatic projects and applying it to home design.

One of his first projects was a home in Webb City, Missouri, near Joplin, where a powerful tornado in May 2011 killed 158 people, destroyed thousands of buildings and homes and caused billions of dollars in damage.

After the Valley fire in 2015, McDonagh, who is originally from California, turned his attention to the North Coast. The Tubbs fire two years later convinced him he needed to open an office in Santa Rosa.

The Willow Green Place concrete home for Fredrickson and Russo is his first fire rebuilding project here, but he’s designing another house on Boulder Point Place, off Fountaingrove Parkway. That home has a flat roof allowing for the addition of a usable rooftop patio space similar to what’s included on some commercial and residential buildings in urban cities.

Though concrete is more fire-resistant than wooden frame buildings, it isn’t totally “fireproof,” said Mike Renner, director of development recovery services for 4Leaf, a municipal engineering firm contracted by Wick’s county department to do fire reconstruction permitting and inspection services.

Renner said the primary concern when reviewing a concrete home is ensuring its structural safety. Even concrete structures begin to fail when exposed to intense heat for long periods, he said.

One effect caused by extreme temperatures is called “spalling,” in which the surface of concrete, masonry or brick is weakened to the point of chipping or pitting. Concrete structures exposed for a lengthy time to extreme heat can appear to retain their structural integrity but actually become brittle, Renner said.

In areas of Sonoma County that are at higher risk of wildfire, a number of steps can be taken to reduce fire risks in traditional construction, he said.

“What will help, along with stronger building codes, is complying with the state’s longstanding defensible space requirements,” Renner said, adding that homes surrounded by at least 100 feet of clear space have a better chance of surviving a blaze.

That said, concrete homes are inherently more fire-resistant than a traditional wooden frame home, he said.

“I just don’t like the word fireproof,” Renner said. “Just like when they built the Titanic and said it was unsinkable - the only thing that’s fireproof is water.”

McDonagh said his price for building a concrete home starts at about $400 a square foot, comparable to what other builders are charging for traditional wooden frame homes. The cost of home construction has sharply increased since the 2017 wildfires, because of increased demand for homes and labor plus materials shortages.

“Contractors are making an exorbitant amount of money,” McDonagh said. “In some cases they’re charging $530 a square foot up in Fountaingrove.”

Fredrickson and Russo’s concrete home, which has a $890,000 price tag, will be completed by the beginning of November. Russo, whose orchid farm in the backyard of the former house was destroyed by the fire, will move that flowering area to the attic of the new house.

The pitch of the concrete roof was increased to about 30 degrees to add another 1,400 square feet of usable space in the attic, McDonagh said. The space will be heated and cooled with no vents.

In traditional wooden frame homes, attics are vented near the eaves. That feature poses a common fire hazard, he said.

Aside from offering greater fire resistance, the Fredrickson and Russo home will be equipped with solar generation and a storage system that will allow it to go off the PG&E grid during power failures and the utility’s public safety shut-offs to curtail wildfire threats.

McDonagh called the couple’s house his company’s “first foray into Santa Rosa,” but said he’s confident there will be more.

You can reach Staff Writer Martin Espinoza at 707-521-5213 or martin.espinoza@pressdemocrat.com. On Twitter @pressreno.