Article No: 75
Concrete Dome is St. Louis' Party Central
By: Carole McMichael
Football fans may not have heard of the "Concrete Dome." It is the Hoette family's nickname for their new, 8,000-square-foot ICF home, which hosted a
Superbowl party for about 150 people. Ironically, the roof is the only part of the two-story home that is not concrete.
Joe Hoette is the president of Hoette Concrete Construction Co., located in a St. Louis, Mo. suburb. He is a concrete contractor who specializes in foundations and a variety of colored, stamped flatwork used for structural decks, driveways, garage floors barrier walls and entry porches.
According to Hoette, St. Louis has been extremely conservative about building; so there haven't been that many ICF-built homes in the immediate area. Further north in Hannibal, there have been around 80 ICF homes. About five years ago, Hoette saw a presentation on ICFs put on by the Concrete Council in St Louis, and that got him started. Since then, he has built four houses and two commercial buildings using ICFs. The last of the four houses was his dream home.
"I've wanted to build my own house for years," Hoette said. "When ICFs came along, I thought it was the perfect opportunity for me to build a concrete house. It is big, so I wanted something energy efficient. I'm on the end of an airport runway, so I wanted something that was quiet. I'm out in the woods, getting water from a well, so I wanted something that was relatively fireproof. What better product could I do it with than the ICF?
"Arxx is the ICF I chose. That is the only ICF I've used and I love it. There is a local supplier, so production wasn't held up when I needed to order extra blocks. You can submit your plans to Arxx and they will figure the number of and which blocks required for you, or they will give you some software so you can estimate them yourself in-house. That is what I did.
"Arxx also gave us a thick spec book and all the support we needed as the architect had not worked with ICFs before. That wasn't the problem. We didn't design the house to fit Arxx dimensions, but rather made Arxx fit the plans. It is not that I didn't think about the specifications; but I didn't take into account all the waste from making the blocks fit the measurements of my plans. Arxx, with a typical block of 16 inches by 4 feet long, will fit any design you have, but that is not the most efficient approach to the process."
Building the dream
Two-plus acres of the 3.5-acre site are the bluff, overlooking the Missouri River, so Hoette had to create a pad, a process that took two and one-half months. The house is 60 feet deep and 120 feet long, plus a circle drive and two garages connected through a port cochere. Basically cutting off the top of the bluff, he had to make a 24-foot deep cut and move a tremendous amount of dirt.
The first floor consists of a great room, a hearth room, a large kitchen and eating room, an entry foyer, a library, a dining room, a guest bedroom and the master suite. The lower level, which is two-thirds walkout, consists of another kitchen, a great room, two bedrooms, a big game room and, off the game room, outside, a hot tub large enough to accommodate 20 people.
The house includes seven baths and five fireplaces — two of which are outside. There also are two concrete bars with colored, stamped faces. The lower-level floor is colored and stamped with wood planks so it looks like 12-inch-wide barn boards. The walls are 16 inches thick (12 inches of ICF and 3 inches of brick exterior) and 13 feet high. They sit on 4-foot-wide footings. Below the structural slab floor of one of the garages is Hoette's 12-foot high golf room.
"I have a driving range with a net," Hoette said, "and in the floor, I poured three cups and put down Astro turf. The rest of the space under the garage is a safe room. It is totally surrounded by concrete with 12 inches of concrete overhead, 16-inch-thick walls and a steel fireproof door."
"I considered using a concrete roof and talked to people about the specialized mix for the Northern climate, but they said that St. Louis has a severe freeze-thaw cycle. Further North, the temperature may go down to 0 degrees F and stay there for months. We have several snow storms in winter; and between each one, we get back up to 50 or 60 degrees F. After consulting engineers, I went with traditional wood trusses, using an architectural shingle that has the appearance of cedar shake, but is a 30-year asphalt shingle. I decided on 100 percent brick exterior except for soffits, which are maintenance-free vinyl.
"The house is not totally fireproof without the concrete roof, but I have a sprinkler system around the entire perimeter of the house. What isn't concrete has sprinkler protection. I also water my forest. It would take a heck of a fire to get to the house.
On the job
The lower-level walls were done in a single pour. The main floor, which had walls that were 10 feet, 11 feet and 14 feet, was also done in a single pour. "There were no blow outs," Hoette said. "We used a six-and-one-half sack (concrete per cubic yard) concrete mix with a small-sized aggregate. We kept the aggregate small so we could vibrate it around the steel, which was a number 4 rebar, 16 inches on center, horizontally and vertically.
"We poured the concrete in January at 18 degrees. ICFs create perfect curing conditions — staying moist in spite of the cold. The tester who came to measure the strength of the concrete was so excited because of the strength it developed in a short time. He would come out every few days and plug his computer into it. Within a week, he was getting 6,000 to 7,000 psi strength readings."
One of the challenges of becoming an ICF builder is dealing with a certain amount of inexperience with architects, crew, subcontractors and code inspectors. In most cases, the ICF distributors have excellent training programs, onsite tech reps and thorough information to aid all parties that need to be educated upfront. This does a lot to ease the process.
Hoette's lead man is his cousin, Les Hoette. He went to a seminar to learn the system; then he and another key crewman were certified during the building of the first Arxx house. These two did all the setting, cutting and lining on Hoette's home with the help of two other crewmen, who were experienced with concrete but not ICFs.
"They love the ICFs," Hoette said, "because the polystyrene is a lot lighter than wood. Also, they can keep working during the winter under almost any conditions — as long as the concrete doesn't freeze in the trucks.
"Everything but the foundation and other concrete work was subcontracted. I talked at length with the plumber who had no ICF experience before he bid the job. The electrician had done one house previously with ICFs, so his bid reflected that he knew what he would be doing. It is a natural tendency in the industry, if you don't know what you will be facing, you add dollars.
"In St. Louis county, conduits are not required for installing wiring in ICF-built homes. The electrician used a hot knife and staples. The electrical box is the same thickness as an ICF block, so he would either glue or shoot it to the concrete wall after he removed the foam. It was simple, almost easier than the traditional hole-drilling method."
There were two places where bathrooms were on an outside wall. Even though it was an R-50 wall, the plumber did not feel comfortable putting the pipes in the block, so Hoette's crew furred out a wall. On interior walls, a sleeve was placed in the wall before the pour.
The local fire department, which also was unfamiliar with ICFs, was in charge of code inspection. Hoette met with them, and went through all the code requirements. Arxx supplied materials and specs upfront. According to Hoette, as ICFs do such a superior job of fire protection, it caught their interest right away.
Keeping warm, keeping cool
"I was going to have an all-electric house," Hoette said, "but the largest electric heater I could find took too long to heat up, so, I went with propane. I buried a 1,000-gallon tank under the planter areas on the lower level. There are three zones: propane heat; a gas cooktop; and a gas fireplace. The rest of the fireplaces are wood-burning."
Hoette decided against radiant floor heating because the furnaces are so energy-efficient. But because of the fireplaces and the tightness of the house, there was concern about having enough fresh air. To circulate the air, he installed an air exchanger that works randomly — run by computers — bringing in outside air and exhausting stale air outside. The goal is to keep positive air pressure in the house.
"I have 142 canned lights," Hoette said. "I can practically heat the house by just turning on the canned lights. In fact, I had to beef up the air conditioning (4 tons) for times when we have large parties — we can easily accommodate 200 or so people. In eight months, we have had seven large parties. You could call it 'party central.'"
Down the road
"ICFs are absolutely a wave of the future," Hoette said. "It is my understanding that about 40 percent of homes in Canada are built with them and about 20 percent in our northern states.
"There is beginning to be a lot of excitement and interest in ICFs among the St. Louis homebuilders. They host an enormous show in February where the local supplier puts on a huge display of ICFs. There also has been a lot of interest from people who are looking for a builder. But I don't have a name for them. This area needs someone who can pick up that ball.