Article No: 13
ICFs in Ottawa
By: CAROLE MCMICHAEL
If what the tract builders select as building material is the litmus test for what has gone past innovative to accepted trend, then building with ICFs has arrived in the Ottawa area of Eastern Canada.
"Use of ICFs is catching on more and more," said John Teixeira, John Teixeira Construction. "Up to this point, ICFs have been used predominantly in custom homes. When tract builders jump on board, the trend has gone to the next level."
Primarily a custom builder, Teixeira got interested in ICFs in 1996. He is an R2000 builder who focuses on providing clients with a very clean living space. Winner of the Ontario Healthy Housing Award in 1995, he noted that in the general population, there has been an increase in environmental illness, which includes sensitivity to all kinds of emissions from building products. Most of these involve allergies to volatile organic compounds (VOCs) and a whole array of different bonding materials and sealers frequently found in wood-built homes. He decided to check out concrete as a healthier alternative.
"I had a great experience in the first year I did ICFs," Teixeira said. "I already had a reputation as a healthy housing builder, so a hypersensitive client come to one of the sites I was building to look it over. We had an ICF system on slab in the dry wall stage. She came in and sniffed around for about 10 minutes. Afterward, she told me that normally if she walked into a house at that stage of construction, she would be on the floor in 30 seconds. This gives you an idea of just how clean ICF construction can be.
"Once I started using ICFs, I stayed with it. I have done only one stick-built house since then. I use the IntegraSpec wall system, which has been out for three years. This is a knockdown block, which is shipped easily in panels. It has a simple system of three components — one panel with two pieces for the corner. It is completely reversible — no top or bottom. The webs, which are made in different widths, are separate, so a builder's stocking costs are a lot less. It has been innovative the way it is constructed. The web material is high impact polystyrene so the part recessed in the block actually bonds with the polystyrene panel creating a very strong form. I have poured a 14-foot wall in one lift without any bulges or blowouts.
"The problem with using some block-style ICFs comes when you stack them — there is a compression from the pour. The weight of the concrete hitting the rebar and webs is actually causing miniscule gaps, so you have to overcompensate around doors, for example. The IntegraSpec system uses a hard contact so that there is no compression — the receiver that is embedded in the foam panel goes right to the top of the block, so each block makes contact with a hard surface, preventing compression. To the builder, that means if he has a rough opening, he can cut exactly what he needs — no compensating.
"Another problem with some blocks is they float. IntegraSpec has an interlocking web system that prevents that. Also, because the system comes in panels, it can be easily ripped on a table saw. I have had situations involving openings or certain heights where I have sliced it as thin as 2 inches high and used it elsewhere. The waste is cut enormously."
Changing to ICFs
One of the concerns when builders switch to ICFs is how high a learning curve they will face and how crews will react. According to Teixeira, the changeover to ICFs was very easy. His building style always had involved a lot of innovation, so his crew was used to trying different things. He found the IntegraSpec system so user-friendly that he has sold the system alone — just the components — to home owners. With two 11/2-hour sessions at the site, plus supervision on the day of the pour, they have successfully poured and built their own homes. The first hour and a half got them started; the second visit got them up to the pour stage. Teixeira would then do a prepour inspection and be present for the pour. With three to four hours of instruction at the most, homeowners with no building experience could build with the ICF system.
Another concern in switching to ICFs is how area inspectors will react.
"With building inspectors who haven't had experience with ICFs," Teixeira said, "I feel it is incumbent upon me to show up with all the data and engineers' stamps. In effect, it is my responsibility to train them to my system. It doesn't take long for them to realize I know what I'm doing. If you are introducing something that is not common, do your homework — you can't expect them to do all the research. They are there to protect homeowners and the public. I've had no problems with that approach. Also, I've spoken to groups of building inspectors and suggest builders offer to do this.
The two-bedroom retirement home in Perth, Ottawa, has 1,900 square feet in the basement and main floor. It was designated an EnviroHome by the Canadian Home Builders Association. To be designated an EnviroHome, it had to meet different criteria on ventilation, energy efficiency and use of VOCs in finishes. It was also an R2000 home, a Canadian concept that has been exported to other countries, including Japan and Russia.
"We have a computer program that has been developed over the years that allows us to do a complete modeling of the home for energy efficiency, involving the effects of things such as solar orientation, overhangs and heat gains and losses. It even takes into account heat gains from occupancy. In the Perth home, we calculated 2.4 kw were produced per day by body heat and appliance use, which turned out to be 26 percent of energy required to heat the house. Because we built the home with a heat recovery ventilator and a very high insulating envelope, those gains weren't being lost. Another 26 percent was provided by passive solar, so the homeowners have to purchase only 48 percent of their energy."
Some of the other energy efficient choices include: 1) R12.04 EPS insulation, ICF walls from footing to roof and ceiling R60 insulation of blown in cellulose; 2) high-efficiency argon-filled windows; 3) a superspacer — insulating urethane spacer that allows higher relative humidity in the winter without condensation; and 4) Wirsbo hydronic radiant infloor heating system in the basement and main floor.
Teixeira also had a solar domestic hot water heating system installed. There were two four-by-eight-foot collector panels filled with antifreeze solution, and a differential controller. The water is heated in a 60-gallon preheat tank. By late spring, the homeowners were getting all the hot water needs met by the sun and were using 73 percent less energy.
The storm of '98
One of the biggest challenges to energy efficiency is the old fashion ice storm. In 1998, a bear of an ice storm came and stayed, leaving people without power for 12 days, which, in the dead of a Canadian winter, is not just an inconvenience but a potential survival issue.
During the storm, a lot of temporary generators and temporary wiring that didn't meet code was called to the rescue. "Now when I build home," Teixeira said, "I automatically prewire it for generator use. We take essential circuits and put them on a separate panel that is normally fed through the grid; but if the power goes off, all we have to do is connect generators and survive. I don't even ask clients anymore.
"The owners in the Perth home had been through the ice storm and were aware of how costly running a gas generator can be over time, so they requested some kind of storage recharge system. I added a 100-watt solar panel to a 6-volt battery system. They also asked for an inverter to convert to 120-volt house current. That gives them the opportunity to be independent. Any excess of electricity is stored in the battery. Every day, they simulate a power outage. A timer set at 8:00 in morning shuts down the hydro to those two circuits and lets the bypass system work all by itself to get the benefit of the energy from the sun."
Teixeira had another enlightening ice-storm story. In an ICF house that had a radiant concrete flooring system using an 8-inch slab and an air-medium radiant heating system, the homeowners lost only about one degree a day when it was anywhere from minus 12 to 15 degrees outside. The owners were both engineers, so they monitored the temperature very closely. Internal heat didn't depend on having power because it was stored in the concrete slab and because ICFs provide such a good heat envelope.
"One of the important points when building with concrete in our climate is to couple ICF systems to radiant floor heating," Teixeira said. "If you don't have that, the discomfort of walking on cold concrete will turn people off. Another thing I find essential is to have a warm surface even at the footings. All our concrete rests on polystyrene, so we put a one-inch strip of foam over the footing, so when the floor is poured, it is completely enveloped in foam that minimizes the heat loss. In the summer, when we have high humidity, homes often get a ribbon of condensation along the footing that will breed mold and mildew and create an unhealthy living space.
"A third must is a good ventilation system. We use an energy recovery ventilator that recaptures energy to heat in winter and cool in summer. The incoming air bypasses the outgoing air through a core that absorbs heat and moisture and pushes it back out through the exhaust. The ventilator can reject 65 percent of humidity and reduce the load on air conditioners. The core does this automatically but there is a central control to handle changes.
George Brealey and his wife are the owners of the Perth home. He noted that there are a few concrete homes in area, but they haven't put together a full energy efficient approach with advantages such as radiant floor heating. He especially enjoys a floor temperature of around 74 or 75 degrees. "You don't feel any chill rising from the floor as in traditional homes and it helps prevent heat loss through the ceiling," he said. "Even with the high cost of fuel this year, we haven't spent a $1,000 yet."
Another advantage of ICFs, according to Brealey, was the soundproofing. When a noisy oil delivery truck rumbles up the driveway, they don't even hear it.
If you are wondering if this special home is a sign of growing interest in ICFs in the Ottawa area, Brealey had a telling experience: "When we had the open house as part of the "Home with a Difference" home tour, we were overwhelmed. We were expecting maybe a 100 people, but ended up having 125 every hour. It was really packed in here."