You can huff and you can puff, but you can’t blow this house down.
That’s because it’s a concrete house, or, in building parlance, an insulated concrete forms (ICF) structure. What are these “forms” and how do they relate to the three-story, 8,000-square-foot house Willem “Wim” Roelandts and his wife, Maria Constantino Roelandts, are building in Los Altos Hills?
Wim patted a wall of their “dream house” and asked, “How do you like our Styrofoam house?”
The exterior of the structural walls is, indeed, plastic foam.
The rigid plastic-foam forms used to build this house are interlocking modular units that are dry-stacked (without mortar) and filled with concrete. The forms lock together – somewhat like Lego blocks – to create a frame for the walls and floors of the house.
Concrete is pumped into the cavities to form the walls. Reinforcing steel (rebar) is added before the concrete is poured to give the concrete flexural strength, similar to that in bridges and high-rise buildings.
The forms remain in place to serve as thermal insulation for the walls. Which brings us back to the wall Wim just patted.
Why would he want to build a concrete house using foam blocks?
“I grew up Europe and I don’t like creaking houses,” Wim said. “This will not creak.”
Obviously, that wasn’t the only reason.
Building with ICFs produces a truly green house. The forms are made from recycled plastic. Because they are lighter weight than more conventional building materials, less fuel is required to deliver them. And less waste remains at the end of the project.
The forms provide insulation and keep the house airtight, which lowers heating and cooling costs.
“There are no gaps in the walls,” pointed out Wim, an avid reader who thoroughly researched ICF construction. “The more I read about it, the more I liked it.”
No air infiltration means no dust or allergens, There are no cavity walls for mold, mildew, bugs or rodents. And there is no off-gassing of materials.
The foam material on either side of the walls can easily accommodate electrical and plumbing installations. And the walls themselves are sound deadening.
“We won’t have to do anything to the walls in our home theater,” Maria said.
Though relatively new in California, concrete houses have long been popular in areas of the country where the weather is more severe. They have a high wind resistance, won’t rot or decay and are fire resistant.
“The house is a concrete shell,” explained contractor Shad Shokralla of Brighton Builders Limited of Los Altos. “The interior walls are wood-frame construction. When the house is finished, you won’t know it’s concrete.”
“I like the solidity and the fact that it’s earthquake-proof,” Wim said as he stood in the two-story foyer of the house.
When the house is completed, a nearly 4-foot-wide Austrian crystal chandelier in a Millennium (old silver) finish will illuminate the foyer. Suspended from a domed ceiling, the chandelier is one of two in the house (the other is in the master bedroom).
“The domed ceilings are manufactured drywall and come in four pieces from Salt Lake City,” Shokralla said.
Shokralla is a principal on what Maria calls their “dream team,” which includes architect Anthony Matisi of CAS Architects Inc. of Mountain View, interior designer Benjamin Garduno of San Francisco and landscape designer Nancy Broadway, also of San Francisco.
The Roelandtses assembled their team when they decided to build after shopping around for a house for more than a year.
“We didn’t find what we were looking for, and we decided if we wanted our dream house, we would have to build it,” Maria said.
They found an ideal piece of property, with an incredible view and ancient oak trees, and started the project a year and a half ago.
In the meantime, the couple is living in a Tuscan-style house in Los Altos, which is appropriate because they spent their honeymoon in Italy four years ago and their new house will be an “Italian villa with a technology twist,” to quote Maria.
Belgian-born Wim, an electronics engineer, has been able to devote time to the project because he retired in 2008 from Xilinx after a 12-year stint as CEO. Prior to that, he worked for Hewlett-Packard for 29 years and held several management positions. He serves on the boards of several companies and charities.
Maria, a native of the Central Valley, worked 15 years as a flight attendant with United Airlines. She then worked for Integnology, an engineering consulting firm in Santa Clara.
Today, she serves as president of the Roelandts Family Foundation and a member of the Santa Clara University Board of Fellows. She spends countless hours on charity work, notably with El Camino Hospital in Mountain View and Heritage Home in San Jose.
“I’m most proud of our scholarship, the Constantino-Roelandts Engineering Scholarship,” Maria said.
The couple’s new home will have ample room to host charity events – a prerequisite in the design. It also boasts a library to house Wim’s books (5,000 or so) as well as a huge closet for Maria.
“I wanted an elegant home with lots of windows to enjoy the beautiful views of Silicon Valley,” Maria said. “I also wanted our home to be comfortable for two but large enough for family visits and entertaining. And there should be no wasted space.”
In fact, every corner and niche is being used. And there are energy-saving features, too, such as radiant-heated floors, solar panels and an electrical thermal system.
The house is tucked into a hillside. In back is a tree-studded hill (a bridge leads from an upstairs deck to the hillside) and in front the landscape opens to a view of the Bay.