On the sidewalk at Willow Green Place, Bill Fredrickson and Michael Russo’s new home looks like a concrete replica of the timber frame houses on the block that was destroyed by the Tubbs fire two years ago.
Like the other houses, it has multiple gable walls, eaves with pronounced overhangs, and steep, sloping roofs – but all of these features are made of poured concrete.
With all the stucco and trim details in place, you can’t tell the difference, Fredrickson said. Using concrete to rebuild instead of wood is a breeze, he said.
“Who in their right mind would build a wooden house in a forest fire area if you could build the same house for the same budget?” Said Fredrickson.
“I wanted to convert it to concrete as soon as I knew it was available.”
The devastating 2017 fire destroyed 5,300 people in Sonoma County alone. Despite their refractory advantages, few concrete houses have been built to replace them.
Greg McDonagh, the contractor of the Willow Green Place house, hopes to change that. McDonagh, president of Savior Structures in Roseville, said the high cost of traditional timber frame construction has now made concrete housing a more profitable option.
McDonagh, who joined the construction business immediately after graduating from high school, has been building residential and commercial buildings for 40 years. In late 2006, he invented a concrete wall molding system with special separators to make narrow plywood boxes for pouring concrete.
The McDonagh’s concrete system removes the plywood molds or boxes, leaving only the concrete, special separators, and reinforced reinforcement. An expanded sheet of polystyrene foam is inserted into the plywood boxes for insulation.
McDonagh, who worked in Utah in 2006, developed his Spider Tie separation system to build basement walls and avoid relying on concrete contractors. Two years after he developed his concrete construction technology, the U.S. economy collapsed and the floor fell out of the housing industry.
McDonagh, whose concrete molding system was already being used by pool builders, turned to the design and construction of city pools, water parks and water tanks. The versatility made it possible to design unique concrete structures and extreme curves.
“We learned that we can build a concrete construction pool for the same, if not less, money than Gunite,” said McDonagh. “The versatility in shaping shapes is where we really shine. We had a motto: “Nobody bends concrete like us.”
In 2012, as the economy was improving, McDonagh returned to home construction, taking what he had learned from pool and water projects and applying it to home design.
While concrete is more fireproof than timber frame buildings, it is not entirely “fireproof,” said Mike Renner, director of development rescue services at 4Leaf, a community engineering firm contracted by Sonoma County to provide permit and inspection services for rebuilding fires.
Renner said the main concern when reviewing a concrete house is to ensure its structural safety. Even concrete structures begin to fail when exposed to intense heat for long periods of time, he said.
One effect caused by extreme temperatures is called “chipping,” which is the process of weakening the surface of concrete, masonry or brick to the point of chipping or pitting. Concrete structures that have been exposed to extreme heat for long periods of time appear to retain their structural integrity but actually become brittle, Renner said.
That said, concrete houses are inherently more fireproof than a traditional timber frame house, he said.
“I just don’t like the word refractory,” said Renner. “Just like building the Titanic and saying it was unsinkable – the only thing that is fireproof is water.”
McDonagh said his price to build a concrete house starts at about $ 400 per square foot, comparable to what other builders charge for traditional timber frame houses. Fredrickson and Russo’s concrete house, priced at $ 890,000, will be completed in early November.