Article No: 12

2006-04-28 07:41:51
The Riverstone house
By: Kyle Dalton

The ICF industry, which is penetrating the home building market in the United States at an ever-increasing rate each year, has migrated north of the border to Canada. And by the actions of the Cement Association of Canada (CAC), the migration won't stop anytime soon.

According to Cameron Ridsdale, director of business development for the CAC in the province of Ontario, Canadians throughout the country are getting an up-close and personal look at the ICF industry through a variety of showcase or model homes constructed of ICFs that are both environmentally sound and energy efficient. "We are exposing the ICFs to the consumer through the showcase homes as well as through media attention," he said.

One such showcase was the Riverstone house, which opened just outside of London, Ontario in 2000. This home, as the case is for all showcase homes, was built by a builder local to the area who had some experience with ICFs or a desire to get into the concrete home sector.

The Riverstone house is built with insulating concrete forms (ICFs) from Ft. Lauderdale, Fla.-based Eco-Block. Photo courtesy of Riverstone Design/Build.

Travis Loyens, co-owner of Riverstone Design and Build Inc., said he was approached by a representative from the Ready-Mixed Concrete Association about the showcase project. "The Loyens family had decided that they wanted to build with ICFs," Ridsdale said. "They were exactly the type of builder we wanted to work with." Because Loyens' company already had previous experience building ICF homes including five in 2000, Loyens accepted the offer.

As might be expected, the construction of any home in Canada can be difficult for the builder and subcontractors because of unrelenting weather conditions. According to Loyens, the construction of ICFs reduces the weather factor to some degree because the structure can be enclosed more rapidly than a traditional wood-frame structure or other structures. "An ICF home essentially allows for year-round building," Loyens said.

According to Ridsdale, even when the mercury dips below 0 degrees Fahrenheit, which it regularly does in Ontario during the winter (it can reach minus 15 degrees), construction can continue on a concrete home. "You can extend the building season with ICFs because concrete develops heat as it sets up. It's an excellent thermal-chemical reaction. With the insulation, it keeps the heat in. It's self-heating and you don't have to buy natural gas or propane to warm it up. It does it by itself."

Photo courtesy of Riverstone Design/Build 

However, when the thermometer reaches minus 30 degrees and/or precipitation such as a wet snow is present, Loyens said it can be a little more problematic. On the flip side, he said summertime temperatures can reach 110 degrees in the same region and the ICFs provide the necessary insulation to maintain a cooler temperature where construction of the home is bearable.

While construction of homes in Canada is unique simply because of the competition with the weather and its adverse elements, the Riverstone House is equally unique in its target audience.

Riverstone Design and Build Inc. has traditionally built homes in rural or farming communities located far away from the city and neighborhoods where homes, simply because of their close proximity to each, other offer some protection from outside elements such as the wind — a benefit most homeowners take for granted. Conversely, rural homes are completely exposed to the elements with the only protection provided by the four walls on the house. As a result, homeowners in these areas are always looking for homes that rate high in energy efficiency.

Along those same lines, Loyens noted that homeowners in the London, Ontario area, which include a large demographic of European immigrants, demand a structure that will last for many years as is the case in most farming communities where families keep a property and tend to it for many years.

"They don't mind spending the extra money because they appreciate the high quality and recognize the circumstances (of living in an exposed environment). And they want a home that can be passed on to the next generation," he said.

Ridsdale said this buying mentality is true for all those in Canada who are interested in concrete homes. "Our target audience consists of people who have some money to spend and can make that value decision that they are willing to pay something to get these benefits."

Those two benefits — energy efficiency and durability — essentially describe a concrete home and in this case, the Riverstone House.

One of the main energy efficient features found in Riverstone and ICF homes in Canada is radiant floor heating. The concept is simple as warm water circulates through tubing that is buried in the floor throughout the house. Instead of conventional forms of heating that address the heat loss of the structure, radiant floor systems address the heat loss of the human body. The radiant floors take advantage of the concrete's thermal mass as they absorb and store heat, then conduct it directly to the feet and to objects in the room that then re-radiate the heat. In short, radiant heat warms objects, not just the air.

Ridsdale said to demonstrate the effectiveness of radiant floors, the radiant heat tubing supplier at the Riverstone house provided trade show bags as the people entered the house. The visitors put their shoes in the bag and carried them around through their tour of the house. Essentially, making those that entered literally and figuratively "feel the heat." "There were lots of 'oohs' and 'aahs' from people who had never felt it before," he said. "People don't appreciate it until they've actually felt it."

"The warm floors are a treat and they work really well with the ICF walls. They are another piece of mass that holds on to the heat so your house stays at a constant temperature no matter what happens outside."

Interestingly, Loyens had to make the heat in the radiant floor system even more efficient because of the basement below. The basement, which is eight feet in depth and recommended at this depth because frost can reach up to four feet below the surface of the ground, featured a ceiling that was built using open-web steel joists. Steel bars and plywood were placed on top of the joists to provide a base for the concrete pour. However, with this setup, heat loss could be considerable with the heat radiating down to the basement. To prevent this, Loyens placed a layer of bubble foil that would reflect the heat back up into the main floor and into the house. After the concrete is poured, the plywood and steel bars are removed and the basement ceiling/main floor of the house are in place.

All these careful considerations and implementations of energy efficiency earned the Riverstone house an R2000 certification, or a certification based on a federal standard developed for building energy-efficient houses.

The certification process starts when the builder hires a third-party quality assurance expert who takes the plans for the home and analyzes them using a computer program. After the computer analysis is complete, the third-party expert produces an energy budget that meets R2000 requirements.

During construction, the expert works in the field with the builder to ensure that R2000 targets are being met. Finally, upon completion of the home, the expert returns one final time to measure the air leakage in the home. The test consists of placing a blower in the doorway of the house. To the pass the test, the house must meet the minimum requirement of 1.5 air changes or less per hour. "This is a considerably lower number of air changes than the typical house," Ridsdale said. "The houses have to be really tight. And they don't get a certificate saying that it's an R2000 house until all that's done."

Ridsdale pointed out that while the overall solid structure of the house plays a large part in achieving R2000 certification, heat recovery ventilators are also a significant contributing factor. "In these homes, when they're exhausting air from the house, they use the waste heat from the exhaust to heat the incoming air. You get a lot of fresh air this way."

According to the numbers, the Canadians are quickly learning about the concrete home industry and are acting on their knowledge. In Ontario, where the Riverstone house is located, 360 homes were built with above grade ICF walls in 2000. In the entire country, 1,400 homes were built with above grade ICF walls in 2000, which represents 1.3 percent of the total single family housing starts in Canada. Since 1997, ICF housing has grown at a rate of more than 30 percent.