Insulated Concrete Forms - Building Innovation

Rica and Gary LaVerda get it all the time, people walking the Moraga-Lafayette trail, passing their home, stopping and asking “what are you guys doing here?” The home they are building does not look anything like the wood frame skeleton we’re used to seeing. The white blocks structure has been drawing so much attention from passers-by that the LaVerda have printed a flyer that explains why they’re using ICFs to build their new home.

ICFs are Insulated Concrete Forms. Imagine hollow polystyrene blocks, interlocking together like Lego pieces, reinforced with steel rebar and filled with concrete, and you’ll have an idea on how to build an ICF wall. The technique was created in the 60’s in Canada and has been used in the United States for about 20 years. “We had been living in our Lafayette house for 30 years,” explained Gary LaVerda, “and when we decided to rebuild it we met with Marty Diefenbach. He introduced us to the concept of ICFs.” The LaVerda were particularly impressed by the durability of the material, its thermal and acoustic insulation performance, and by its safety both from a fire and earthquake points of view.

“These homes made with ICFs are built to last 300 years,” says Marty Diefenbach, partner in Diefenbach and Barrett, the contractor building the Lafayette home, “they are resistant to fire, don’t attract termites, resist to mold, provide superior sound insulation and keep the house cool or warm.” The LaVerda worked with EnergyWise, a consultant specialized in sizing and saving energy for family homes and as a result they ordered heating and cooling equipments sized for a 1200 square feet home, when theirs will be 2800 square feet.

“The insulation rating of a home built with ICF is R60, compared to a R13 for a wood home,” claims Diefenbach. In fact the insulation is so good that a special automatic ventilation system has to be installed to make sure the house is properly ventilated. “That may be one of the disadvantages of the ICFs,” says Chris Avant, President of Canyon Construction a local leader in sustainable construction, “you have to think carefully about your aeration because ICFs are so tight.” Avant thinks that ICF is a good system, especially considering the energy gains over the operating life of the building. The drawback for him is the foam, a petroleum based product that surrounds the concrete. Concrete itself is a material that requires a lot of energy to manufacture. “We recommend the use of at least 30% fly ash in the concrete,” says Bill Juhl, President for the Pacific Region of Amvic, the company that manufactures the ICFs, “70% in weight of the foam of our blocks is made of recycled material and the steel rebar is 100% recycled.” Juhl said that in any green rating system ICF homes get points for thermal performance, ventilation, no emission and use of local material (in the concrete).

Besides the thermal performance, what sold the LaVerda is the safety aspect of this type of construction. “Both wood based homes and our ICF homes are engineered to maximize occupant safety in an earthquake,” says Juhl, “a wood frame will twist and shake but shouldn’t collapse. ICF frame doesn’t twist, it rides the earthquake like a wave and won’t collapse.” According to the Amvic Director both types of homes are safe, but the ICF ones won’t require as much repairs. With fire, he is even more convinced of the advantage of his product. “Our system helps with compliance to the new fire codes,” he said and added that when all the wooden homes burn down, the concrete ones stay up.

If you plan to look at the ICF blocks being installed in Lafayette, you’ll have to hit the trail quickly. Once built and covered with whatever finish they choose the LaVerda’s home will look like everyone else’s. “We’ve chosen a craftman style looking house that will be classic in looks but will incorporate 21st century technology,” said the LaVerdas.