This article appears in the May 2005 issue of Concrete Homes.
Customers Drive ICF Market
By Carole McMichael
Many contractors in the residential building industry are encountering clients who are asking for a concrete home. The power of “word of mouth” is undeniable: Many builders consider former customers, now happily living in concrete homes, their best marketing tool.
The first concrete house built by Joe Bailey’s Polysteel of Austin is an excellent example of the power of word of mouth. The 3,500-square-foot house, costing about $150 per square foot, added about $15,000 to the upfront price in comparison to wood-frame construction, an increase of $67 a month in the mortgage payment. However, the owner is saving $100 a month on energy costs. And because he needed only one ton for every 1,000 square feet, the HVAC cost $4,500 less than it would have in a stick-built house. The upshot: The owner passes on that he is living in a better home and it is costing him less.
“The Austin market for ICFs is definitely on the rise,” Bailey says. “One of the reasons is that we are hitting a lot of the shows and getting information to the homeowners, who are the primary beneficiaries of this technology. It appeals to the owners more than to the spec-home builders, because the builders don’t know they have a sale until they have a contract. The market targets the custom-home customers and energy-conscious, educated consumers who go on the Internet.”
First time with ICFs
Joel B. Katz, president of Katz Builders Inc. in Austin, has been building and remodeling stick-frame houses for 20 years. Although he had seen concrete housing systems at builder shows, he was deterred by the price differential. Unless a customer asked for concrete, he wasn’t going to take the chance – which, of course, is exactly what happened.
Because the homeowner’s builder was comfortable with the Polysteel distributor, Katz soon met with Bailey to investigate the product. “We have a three-day, hands-on training program for builders and crews to become certified,” says Bailey. (For more information about the program, visit masterbuilderhomes.com.)
For the first house, there is a learning curve,” Katz says. “But like any project, the more of them you do, the more efficient your crew becomes, and the more comfortable with the system the trades are. So this brings the price down somewhat. All in all, [the first Polysteel experience] went very well.”
Katz points to one specific area in which the concrete system was particularly useful and cost-effective: “From the architectural point of view, what I like about using the ICF is the thickness of the walls,” he says. “A lot of the houses in this area are Old World-style, where you have 12-inch walls. In wood, that would require double framing; the ICF wall is thick to start with. I also like ICFs because they are sound-deadening and energy-efficient. It makes a strong wall.”
Another place ICFs are more cost-effective than wood is below grade. “We can do the below-grade concrete walls cheaper than slab contractors can,” Bailey says. “We have hundreds of walkouts done every year. The [slab contractors] use steel forms that have to be put up and torn down two weeks later. Then they have to waterproof. If you build that wall with our system, we are two to three dollars cheaper per wall surface area, and the electrical can be run right in the polystyrene, saving more time. The longest it has taken us so far is five days.”
The only subcontractor Katz had to find was for the Polysteel framing, and he turned to Bailey for help. At that point, Matt McCoy’s South River Construction joined the team. Katz had worked with the other trades for years, and most of them had some experience with concrete block walls. Because they hadn’t worked specifically in ICFs, however, he trained them in making attachments and doing the routing in foam with a chainsaw for the electrical. The only complaint he heard from the ICF crew was that in the bright summer sun, the white forms were blinding.
“None of the trades had a hiccup, and the house worked out well,” Katz says, “but we had some challenges. One was that we were told the walls would be within 3/8-inch tolerance. Some weren’t. A second challenge was that window openings needed to be bigger. Knowing what I know now, I would make openings at least 1/2 inch to 3/4 inch wider than called for so there is a little wiggle room.
“In the planning stage, we were on a restricted budget architecturally, so we had to find a plan that we could modify. The plan we found was for a house that had a stone veneer around it, so that made it easy to accommodate a 9 1/4-inch wall using Polysteel and stucco. With a typical plan, we would have had to add to the foundation.
“Once we modified the plan, we met with the key players: the stucco people, the electrician, the plumber, the HVAC guy, the sheet rocker, the trim carpenter and interior and shell framers. It is more cost-effective to have different framing subs. Originally, I wanted to go with just one. The Polysteel contractor was good to work with, and his crew was able to do the framing, but his price was more, so I got my own framer, who had done a concrete house prior to this and was familiar with some of the challenges we had. The reason for including all those subs in planning is that they have to interface with the Polysteel wall. If they know going in what is involved, they are in a better position to bid the job.”
The total framing for the Polysteel project is 4,500 square feet, with an air-conditioned area of 3,372 square feet. It is a two-story home with stucco and some stone around the front entry and a portion of the three-car garage. It has a composition roof and vinyl windows. There are three bedrooms, a media room, an exercise room, a study and a storage room upstairs.
Erection began with a monolithic slab, pouring footings and slab together. The rebar comes out of the slab 24 inches on center vertically and is installed 32 inches on center horizontally. The Polysteel courses are stacked up to ceiling height – 10- and 11-foot ceilings on the main level and nine-foot ceilings upstairs. Using a pumper, the entire first floor is done in one pour. The stacking for this project took about two weeks. Katz noted that they ran behind a comparable conventionally framed house at this stage, but finished the house about a month ahead.
“We do the second wall right after we do the first wall,” Katz says. “Typically, there is seven days before we do the second pour. It cures while the second wall is being stacked. Total building time was eight months.
“To attach the roof, we put in a wooden top plate on top of the blocks – a flat nailer. The rebar goes up through drill holes, using anchor bolts. The roof trusses are attached using special metal hangers. You have to be really careful because it is critical to get the proper height and position of these hangers.”
Expanded foam insulation was installed wherever insulation was needed, including in between the rafters in the attic. This created a sealed attic, making it a conditioned area. This allowed the duct work to be installed in conditioned space, rather than in the grueling Texas heat. Between that and the ICF wall, the house required only one 3 1/2-ton HVAC unit; a wood-frame home of the same size would require at least two.
“The only unusual design feature in this house was the litter box that went through the wall,” Katz says. “In the water heater closet, in the garage, adjacent to the utility room, they were able to block out a hole in the ICF wall to build a space for a litter box.”
Floors of choice
“All the floors were stained and scored concrete,” Katz says. “To install concrete floors, you pour the slab, and wait about seven days. When you come back, you score it, depending on the pattern. We have what I call the ‘concrete policemen.’ During the erection process, you don’t want the crew to mark the slab or drop screws, etc., but you also don’t want to cover it at this stage because there would be too much moisture building up. So you keep it uncovered and try to keep it clean. We have done it for so many years that we are comfortable with it.
“You have to score the foundation before you frame. The framer has to come in to layout the walls. After he snaps lines, the flooring people will come in and do their pattern with a handsaw with a special blade, and put the grooves in the concrete. I don’t like to score concrete when it is hot, because it sets up a lot faster and has a tendency to shrink.
“We use a penetrating stain – a two-step process. Different concrete mixes absorb the color differently, so we don’t use retarders in our mix because it affects the stain. The weather here usually doesn’t get cold enough to affect the staining. It is put in right before the sheetrock, and then we cover the floor until the last weeks of doing the house. For that, we lay down a thermoply – 3/8-inch sheathing – but not all the way up to the studs. You don’t want it under the sheetrock. It is lined with paper and lapped under the stud. When the sheetrock is installed, all we have to do is cut the paper, and keep our fingers crossed that when we pull it off, there is no serious damage. Concrete flooring is very energy-efficient and probably the most cost-effective hard surface, and it adds a lot of character to the floor.”
Will Katz be doing more ICF homes? “Yes,” he says “you always need to add to your portfolio. The more things you can do, the more products you have to market. I imagine [the future ICF market ] is going to be good. It goes back to making people aware of the product. Innovation in home building needs to be consumer-driven. If someone comes to me to do it, no problem. It is duck soup.”