ICF: An Idea Whose Time Has Come
June 2006You would think that in an industry impacted by various major issues—
- Buildings and works-in-progress destroyed by hurricanes and tornadoes, earthquakes and (wild)fires.
- Significantly rising energy prices.
- Lawsuits over mold and health concerns over sick buildings.
- Speed of construction, meeting collapsed deadlines as general contractors pant over lost dollars the longer the clock ticks.
-Concern over the environment and dwindling/increasingly costly resources would jump boots-first into using an exterior-wall construction system that delivered seriously on
- Strength against the worst nature or life can throw at a building.
- Greatly reduced energy requirements.
- Eliminating mold and insect infestations.
- Speeding up construction and earning federal tax credits for builders.
And all for a price tag ($8 to $12 per square foot, including labor and materials, with the inside wall left unfinished) that is currently only a couple of percentage points higher than the cost of building traditional wood-framed buildings—and likely to drop lower as the economics of scale enter in.
Well, this solution is Insulated Concrete Forms. It may only have represented 4 percent of the total single-family-home construction in 2003, but its market share has grown more than 100 percent in the last six years. ICF appears to be gaining acceptance, having been included in building codes after the establishment of minimum dimensions and standards, and can be predicted to changed construction methods widely and dramatically in the years ahead.
In a nutshell, ICF systems use large brick-shaped insulating foam panels as forms for steel-reinforced poured concrete. One ICF form covers more than 5 square feet of wall area.
Installers simply stack, brace and pour. The system includes insulation, vinyl window and door bucks, embedded anchor bolts and trusses, inside and outside furring, and finish-ready exterior and interior walls. The system outperforms standard wood-frame and masonry construction in just about any category you care to consider.
Gary Dillman, CEO/owner of Baylor Plastering & Drywall, Inc. in Central Florida, is certainly sold on ICF. He just acquired Titan Walls after successfully putting coatings over Titan’s ICF walls for several years. "I had even been including Titan’s pricing into several of my bids as a subcontractor,” Dillman says. "Titan Walls has well over 14 years of ICF experience and is no doubt one of the best in the industry.”
"What you hear a lot of in regard to ICF in the industry is that ICF is a great product but when GCs get to the coating, there’s a problem: They can’t find anyone to apply the coating properly. That’s where Baylor comes into play, why we created our Titan Walls division. There are many ICF installers and numerous plasterers and drywallers, but few that do both. When you can do the entire wall, the GC knows you are going to do the walls properly because you’re the one who has to make the interior and exterior coatings look good—no one to blame or pass the buck to. Doing both gives us a leg-up on contracts. Otherwise, the kind of thing that can go wrong with a lot of coating applicators on ICF for instance—usually the guys operating out of pick-up trucks—is they think they can run stucco over Styrofoam without having it fully meshed in or putting some kind of lathe on it. They just want to be in and out of there and don’t really care about the long-term effect.”
Deadline? No Worries!
Titan Walls is just finishing work on a 14,000 square-foot office build-out on Orchard Street in Ormond Beach for M.L. Underwood Construction. Mike Underwood is owner, contractor and developer. "Time is money for him, the sooner he gets the Orchard Street project up, the better,” Dillman states.
"From a clean slab, we built the 20-foot high side and front walls with 34 openings in ICF (leaving the rear wall of 13 feet, 4 inches open for forklift ingress and egress) in eight days. We probably knocked off three weeks from the schedule—poured solid, cleaned up, bracing up the walls, ready for windows, etc. There’s no masonry or any other form of construction that can match that speed using only an average of a three-man crew.”
Other projects chosen at random from various GCs demonstrate this speed benefit. A cinema owner began construction two months after a competitor nearby. He had chosen ICF because of its speed and opened weeks ahead of his competitor as a result. The exterior ICF walls of Marriott’s 49,000 square-foot Grande Lakes Exhibit Hall in Orlando, Fla., went up in two months, shaving six weeks off the total construction time.
"We used a bracing system specifically made for ICF work that goes against the wall every 6 feet and is adjustable in height up to 24 feet,” Dillman continues. "You see a lot of people using make-shift bracing that does not allow you to get the wall really level and requires a lot of work and lumber. Ours is a system of braces and ladders that doubles as scaffolding from which we can stack the blocks as well as pump the concrete. All the bracing is on the inside of the building on solid slab, so it’s all clean. Looking from the outside, all you see is these white walls going up.
"However, it still takes some skill to install ICF, but it is very user-friendly—especially in terms of lifting when compared to concrete blocks, beams. ICF forms weigh in at an average 6 pounds each, making for fewer injuries and insurance claims (and lower transport costs). The system goes together like Lego® blocks, but you do have to have concrete knowledge, shoring skills, and general building and carpentry experience to make sure everything is squared up and the walls level. Our motto is that it’s not a mistake until it’s poured, but once it’s poured, you could lose a wall.
"There are approximately 50 manufacturers of ICF; we use primarily AMVIC and Reward Wall Systems, which we consider to be the better ones. Their customer service seems to be the best, and the blocks are more substantial: straight and locking together tightly, with the integral furring lining up and the ties part of the block—whereas with other manufacturers, you have to install ties while stacking. These two manufacturers work very well technically, getting you the engineering details you need on a really fast turnaround. We are often trying to compete with buildings already quoted on masonry, and we try to convert them to ICF. That needs a quick turnaround on engineering drawings. On this Orchard Street project, three days before starting work, the drawings were already permitted for masonry. Three days later, we had the shop drawings redrawn and submitted to the city and had started construction with ICF.
A Contractor’s Delight
For the applicator, ICF combines the forming, insulating and preps-for-finishing functions in a single step. The system reportedly is user-friendly as well as easy. Says Mike Underwood: "This was my first ICF job, so there was a bit of a learning curve on the fastening details on the doors and windows, but nothing too difficult—I was comfortable with them after doing them once.”
Dillman agrees: "The system has an integral furring system that allows you to attach your drywall directly to the foam. The same is true on the outside, with furring strips every 6 inches allowing direct attachment of lathe and stucco, brick and siding. The blocks are reversible, and as long as you line up the little groove on each block as you stack them, the furring strips will be locked on automatically. Compare this one-step process to a masonry wall where you’d need to come in and install your insulation and furring strips as additional steps.
"You can save more money on the drywall because you no longer need that thickness of drywall. Typically, you’d use 5/8 or 1/2 inch, whereas with this you just need the drywall as a skin to put a coating on and can drop to 1/4 inch. There’s no void behind it, just solid concrete. If you tried to hang 1/4-inch on stud, it would be flimsy and not meet proper requirements to receive finish or textures.
"We coordinate with the electrical and mechanical trades to ensure their installation goes easily. With ICF, they just use hot knives or hot groovers, cutting a little slot to run their pipes and electrical wires. On the verticals, they just cut like they would any insulation foam. On the horizontal, you would think you’d hit the furring strips, but you don’t, because the strips start about 1 to 1.5 inches away from the edge of each block, leaving a 2-inch channel where the blocks meet for conduits to be routed.
"ICF is easily adapted to any floor plans and can shape any angles, arches or radii. Any exterior wall treatment systems can be fastened with screws or nails to the plastic or steel components holding the forms together. For TAFS (Textured Acrylic Finish Systems), because foam is already in place with the ICF, we just rasp the foam, cut any grooves we may have, base coat, mesh it and run finish. All the major EIFS manufacturers have details for ICF. We prefer Sto because they work with us very closely to come up with details and solutions for each situation.”
Underwood confirms: "When the architectural detail is completed on the building, you won’t know whether it’s block, ICF, concrete or stucco. ICF accommodates all the architectural details we want to put on the building, and the result is a very exciting-looking building.”
Dillman says that Canadian contractors are sold on ICF, especially for below-grade basements for its insulation properties. "They battled for several years to waterproof ICF properly,” states Dillman, "and finally mastered that. ICF is now used all year long in residential and commercial construction because ICF blocks can be stacked in cold, snowy or freezing environments where framing or masonry work cannot be done. You can stack ICF in really cold weather (during which the block acts as insulation, saving costs) and then when the weather warms up on another day, you can pour the concrete.
"If contractors are willing to accept the change,” continues Dillman, "they’ll find ICF to be a very enjoyable medium to work, and it will come in labor-wise at about the same contract amount. The key point is that one is working in a medium that is poised to take off like a Cape Canaveral rocket.”
A No-Brainer for Owners
Underwood is an example of an owner who has signed on to ICF: "I am the owner and GC of the Orchard Street project. The long-term plan for me is to hold and lease the property. Half already is. I went with the system from my perspective as an owner. For me as developer, it costs only slightly more, but as the owner, I wanted something that would last a long, long time and not give me any problems. I would certainly recommend the system, as a GC, to an owner because the slightly smaller upfront costs are well offset by future savings. In fact, weigh in the time factor on a larger project, and compare a month of income from a tenant with the cost of longer construction for conventional masonry, even the dollar difference up front becomes negligible.”
From the owner’s perspective, there are several pluses. As Dillman recounts, "Benefits of ICF include being able to stand up to in excess of 200 mph sustained winds, and some have even held up at an F5 tornado, with winds around 300 mph. After Katrina, the only house left standing in a 3-mile radius on the Gulf Coast was made of ICF. Its shell was completely intact despite the winds, rain and floodwaters, whereas the masonry and wood frame houses all around were leveled. Part of the reason for this strength is that the stay-in-place forms allow concrete to cure up to 50 percent stronger than concrete in traditionally poured walls.
"Also, steel strapping members fixed into the top of ICF walls create secure attachments for roof framing. One man reported half the trees in his yard being lost during Hurricane Ivan in 2004, but his ICF home ‘never shook or rattled’ and ‘was not damaged at all by the 160-plus mph wind gusts.’ ICF seismic ratings are also superior.
"When it comes to wild or other fires, the foam is treated with a fire retardant and will not support fire. The concrete, naturally, is a fireproof material. The resulting 3-hour fire rating on an ICF wall after it is poured, four hours after hanging drywall, will defeat all but the most persistent of conflagrations. All these tested safety factors qualify ICF structures for insurance reductions.”
Energy and Environment
As if the assurance that one’s building will remain standing bar a direct hit from an asteroid or atomic bomb, there’s the remarkable energy efficiency to enjoy.
With an equivalent of up to R50 (compared to the R12-17 achieved by 2x4 wood-frame construction), due to tight construction, thermal mass and insulation on the weather side of the concrete, a 50-80 percent reduction in heating and cooling bills is the norm—meaning A/C units must be downsized by about 50 percent from normal requirements, or the units won’t run. Think of monthly electric bills around $50 for an 1,800-square foot home.
Two movie theatres in the North with similar heating systems were measured against each other for heating costs one winter. The ICF building consumed 3,229 therms heating 54,000 square feet (16.72 square feet per therm) while the other used 5,938 therms to heat only 40,000 square feet (6.73 square feet per therm). The ICF system has the added benefit of keeping interior temperatures constant throughout the building. All the above qualifies ICF buildings for energy rebate programs.
Low environmental impact is another ICF characteristic, Dillman reports. "ICF helps architects meet LEED requirements in part because they put a lot of fly ash in the concrete, which is then kept out of the waste stream,” he says. "Some manufacturer’s forms are made of 60 percent by weight of recycled materials and employ no harmful processing techniques or chemicals, such as CFCs or formaldehyde. The average ICF residence saves about 10 trees in exterior wall construction, reduces construction waste (a mere 1 percent construction wastage that itself is 100 percent recyclable in some ICF systems), and energy consumption and emissions by the owner. The new energy efficiency act offers federal tax credits to the builder, not the owner, for using energy efficient products, and ICF is one of the major products that contributes to energy efficiency. The credit is up to $1,800 for a residence and $1.80 per square foot for commercial buildings. It takes a little homework to get that credit, of course.”
As there is nothing organic in the wall systems, bugs—especially termites—won’t be found in ICF buildings. The absence of airborne dust and allergens, and the moisture conditions for mold spores and mildew to develop, makes good air quality another major benefit. ICF walls are so tight that outside pollution and moisture cannot penetrate the walls. The danger here, of course, is that without airflow, any air pollutants in the house will not be able to exit, requiring fresh air exchangers or air ducts to lower indoor pollution levels that can build up.
Noise elimination is another benefit, especially important to buildings near to road and air traffic, as well as hotels, motels and hospitals. ICF has a Sound Transmission Coefficient rating of 54-plus. With exterior, demising and partitioning walls between units made of ICF—meaning 2.5 inches of foam on the outside, then 4 to 6 inches of concrete (depending on the form you use), and 2.5 inches of foam on the inside—you’re not likely to hear a gunshot outside. This was important to the owners of Florida’s 144,000 square-foot Pinellas County Federal Reserve Building, recently constructed with ICF. In addition to energy efficiency, their reason for selecting ICF was not just eliminating the sound of a gunshot, but any bullets that might be directed their way. In actual fact, bullets are hardly an issue, either: When 50 pounds of TNT was detonated just 10 feet from an ICF wall, it didn’t even crack.
Another obvious market for ICF from the soundproofing perspective is cinemas. One GC reported that only one layer of wallboard (instead of the normal three layers) was used on either side of the demising walls in a cinema he was building. The savings in terms of labor required to install wallboard in an area with sloped floors and stadium seating was significant.
ICF has been available on the market for about three decades, its beginnings in Europe. "The system is beginning to pick up in the States,” Dillman notes. "There’s the usual liability of poor workmanship giving a product a bad rap. We’ve fixed a lot of projects installed sub par by someone not properly qualified in ICF. But once we have done one ICF job for a builder—properly of course—they are sold on the system.”
Maybe ICF is one of those ideas whose time has come as the right-now viable answer to an army of problems. As the Frenchman Victor Hugo once said, "There is one thing stronger than all the armies in the world, and that is an idea whose time has come.” An idea that can withstand hurricanes and tornadoes, head off lawsuits, and keep owners, GCs, subs, accountants and tree huggers happy, has got to be worth a look-see.
About the Author
Steven Ferry is a free-lance writer based in Clearwater, Fla.