Building with Resources in Mind
Architect David Horobin break ground on a new family project with his wife, Lynn, and boys, Andrew, 16, and Chris, 12, right, and Chelsea, the Retriever, to build a “green” home. Milton/Register
Right now it appears David Horobin is building a dream igloo, instead of a dream house, in Alta Heights.
Few curious onlookers realize that the white foam blocks — technically known as insulated concrete forms — all over the place are a significant part of the Oxford-trained architect’s long-planned “green” home for his family in Napa.
“People think I’m a nut case,” said Horobin. “One woman said to me, ‘I can’t believe you’re building a house out of those.”
No stranger to green architecture, Horobin, who moved to the U.S. from England in 1978, has been designing with the environment in mind throughout his career. Many of the ideas and materials he’s used over the years are being incorporated into the house he’s designed for his wife, Lynn, sons, Andrew, 16 and Chris, 12, and dog, Chelsea.
In fact, the project he and contractor Patrick Bentley of Bentley Construction and Concrete are building on Montecito Boulevard has so many interesting innovations, the Register has decided to follow the project over the next six months — the target date to finish is December so the family can celebrate the holidays in their new home — and pester Horobin and Bentley with questions about just what it means to build “green” in the year 2008.
Defining ‘GREEN’
“Green,” Horobin said, “is the weaving together of many disparate, energy-efficient, resource-efficient, people-friendly practices in the design and construction of our buildings.”
Horobin, who lost a home in the Los Gatos fire of 1985, said, “It means it will last and sustain the elements, including fire.
“When we moved here in 2001, we had a plan to buy a piece of property and build a house,” Horobin said. When they found a site, he developed the plans and broke ground in early June.
“One thing I believe is that if you affect people around you, (the design) should be sensitive,” Horobin said. In his case, it meant coming up with a plan for a hillside house that that wouldn’t destroy the view of his neighbor, who’s been living in her home for more than 40 years.
“I designed something to maximize the views for everyone,” he said. He even generating computer images of the proposed project as it would be seen from the deck of his neighbor’s home.
The 2,700-square-foot house is built on a lot where there the slope descends 40 feet very quickly. “Laying the foundation on a graded hill is the slowest part,” said contractor Bentley. “We hit bedrock on the second day.”
Insulated Concrete Forms & ARXX Green Build System
With the foundation in place, however, the innovative walls are going up swiftly. The building material is, indeed, blocks, which look like the environmentally unfriendly Styrofoam, but Horobin explained, are no relation (“We don’t ever want to use the word Styrofoam,” he said.) This, rather, is a form of polystyrene “which has no CFCs (chlorofluorocarbons),” he said.
The insulated concrete forms lock together like giant Lego blocks, and then are filled with cement, Horobin explained. Presto, you have a wall that’s insulated and fire-proof to boot.
“One of the biggest things for me about the house is I want to protect my family,” Horobin said. “The shell will be as fire-resistant as you can get.”
The house is being built from insulated concrete forms produced by Arxx Building Products, but the garage and retaining walls are using blocks that Horobin designed, called H-Forms.
Insulated concrete forms are easy to assemble, Horobin said. He and his family put together the retaining wall on the building site and would be helping raise the walls.
“It’s the old concept of the owner/builder,” said Horobin. “Like the barn-raising, this brings it back to where it can be a family project.”
“It saves hours and hours of labor,” said Bentley.
The Pool as part of Energy Efficiency
Another part of the plan — and one Horobin said had city of Napa Planning Department officials scratching their heads — is the innovative heating and cooling system the house will use: It’s all based on the swimming pool. This system — which will be the subject of an more in-depth article later — use heat from pool water to warm the house in winter and then reverses to take heat from the house to heat the pool in the summer. The heating will be in the form of radiant heat, which, in Horobin’s design, it will be channeled into the ceiling. “The pool becomes part of the energy efficiency of the home,” Horobin said.
The first time Horobin used this technology — in 1984 — it worked so well the pool became too hot to swim in, he said. But he’s been able to make adjustments.
“I believe that all the energy we need to heat and cool (our buildings) is in the ground and comes from the sun,” he said.
“It’s a true clean system,” said Bentley, who is using the same system in the house he’s building for his family and which is also being constructed from the insulated cement forms.
A Family Project
Bentley, Horobin and his family all met with the Register to discuss the project. “We’ve talked to the kids,” Horobin said, “Not many people get to build their own house — to design their own house and to use their own projects.”
While the boys climbed around the building equipment and threw rocks, Lynn Horobin said, “We’re having a blast. The more we get into it and see the design, in my heart I feel like I’ve already moved in.”
“The most interesting client to work with is your wife,” observed Horobin. “I’m smart enough to know that the kitchen and interior stuff belongs to Lynn.”
“Good call,” said Bentley.
The Green House Project will run the fourth Saturday of each month. Forward questions for David Horobin or Peter Bentley to Sasha Paulsen, spaulsen@napanews.com. Next month’s topic: Building green and friezes.
ICF Wall Systems
Buildings Home > Sustainable Design > ICF Wall Systems
Wall system offers energy efficiency, durability, safety—and sustainability.
Insulating concrete forms (ICFs) have been gaining steam in the residential market during the last 10 years: concrete homes currently account for about 16 percent of single family construction. Lately, more architects and builders are also exploring ICFs as an option for light commercial construction, capitalizing on the system’s energy efficiency, durability and ease of construction. Commercial structures built with ICFs are poised to reap the environmental benefits of the building system on a grand scale, creating longer-lasting, more comfortable businesses that will provide healthy environments for employees.
ICFs are stay-in-place forms for casting concrete walls. The foam forms are available in a variety of sizes and configurations, which are placed in the shape of the structure and connected with plastic ties. As the forms are placed, reinforcing steel is installed to provide additional support. Concrete is pumped into the forms and allowed to harden. The resulting wall typically has two inches of foam insulation on each side, sandwiching approximately four to six inches of concrete. The interior and exterior of these walls can be easily clad with many traditional materials.
Energy Savings Help Achieve LEED Credits
In a typical ICF home, energy savings are significant, usually in the neighborhood of 15 to 35 percent less than conventionally framed construction. The ICFs’ heavy-duty insulation and concrete’s thermal mass help even out temperature swings in even the most dramatic climates. And HVAC systems can be designed on a smaller scale, further cutting costs at the front end of construction.
Research conducted in the U.S. has shown that the bigger the ICF home, the bigger the efficiency benefit. Proponents of the system’s use in light commercial construction say there is an obvious correlation: commercial buildings stand to benefit greatly, says Ed Alsamsam, PhD, PE, SE, LEED-AP, and manager of PCA’s buildings group.
“Most commercial buildings pursue LEED certification based on at least meeting the applicable ASHRAE requirements or exceeding them. In those cases, they are mostly improving mechanical systems’ efficiency and design to achieve enhanced performance over ASHRAE,” says Alsamsam. “ICFs are a building system that can achieve similar gains in building performance and potential LEED points in the Energy and Atmosphere category,” he explains.
“As designers try to get low-rise commercial buildings LEED certified, they need to tackle the issue of energy performance,” Alsamsam continues. “They have been honing their skills in terms of mechanical, electrical and piping equipment to minimize water, heating, cooling, and lighting needs. A building designer has the ability to make the single greatest impact in making the building envelope efficient, and ICFs provide superior thermal performance.”
Durability: Buildings That Last
As the sustainable movement grows, more emphasis is placed on life cycle assessment and analysis, an examination of the long-term costs of building green compared to conventional techniques. When it comes to optimizing life cycle costs and benefits, ICFs are a great fit, providing unmatched durability that ensures the structures will last for generations. Many structures built with concrete are designed for 100 years of service or more, and ICF buildings are no exception.
In fact, the government is starting to embrace ICF technology for its durability and strength, using it to meet blast resistance requirements on projects like the Florida Armed Forces Reserve Center, a 140,000-sq-ft multi-use complex in Pinellas Park, near St. Petersburg. “Since September 11, all military buildings must have force protection built in,” explains William Murray, project architect with URS Corporation, designers of the complex. “ICF construction was the most cost-effective way to achieve that.”
Speed and Ease of Construction
On the job site, construction is quick and simple, says Joseph Lyman, executive director of the Insulating Concrete Form Association (ICFA). “For large commercial jobs, speed of construction is one of the biggest reasons for using the technology,” he says. Materials can be stored on-site during construction, and leftover forms can be used on other projects, so there is little construction waste. Fast erection times minimize truck traffic and disruption to the surrounding community.
Quality of Life
Beyond increasing energy savings or ensuring durability and safety, ICFs offer some basic benefits that boost employee productivity and enhance the health and well being of building tenants. The thermal mass of concrete walls ensures evenness of temperatures, providing a comfortable working environment no matter the season. The monolithic construction method reduces air infiltration, boosting indoor air quality. Solid concrete walls help reduce sound transfer, providing a quieter work environment. All these benefits add up to more comfortable, inviting workplaces, which help businesses attract—and retain—the best employees.
Poised for Growth
According to the ICFA approximately 22 percent of today’s ICF construction is commercial work, concentrated in markets including schools, light construction, strip malls, agricultural projects, jails and prisons, and smaller public and private office buildings.
Lyman says there is real growth potential in multi-family housing developments, retirement communities, warehousing and storage facilities, hotels and government structures. “Anything eight floors and below is prime property for ICFs,” says Lyman. “This building method is really starting to make a serious dent in the way people build commercially, and I have no doubt that in a few years, ICF commercial work will equal what’s being done in the residential market.”
Alsamsam agrees, predicting ICFs will quickly take hold in the sustainable marketplace. “The range in sustainable benefits from ICF systems is tremendous. Energy efficiency and indoor air quality are attributes that support LEED points, while durability, occupant comfort and disaster resistance are sustainable qualities that reach beyond the current LEED rating system,” he explains. “They’re going to address sick buildings, employee retention, building leasing, owning and operating in the long-term, life cycle costs and their importance to the owner and developer.”
Credit: PCA Portland Association.
