Frequently Asked Questions
What is ICF?
In a sentence, the most superior method of building construction ever invented.
ICF is a concrete shell that offers the greatest protection against hurricanes, tornadoes, fire, and termite (as well as other insects) damage. An extremely “green” (tree-saving) technology, ICF offers tremendous energy savings and due to its airtight insulating panels and solid, reinforced concrete walls, ICF is many times more soundproof than conventional building methods. ICF is even bulletproof!
Insulating Concrete Form (ICF) houses are so superior to conventional wood-frame building construction, one has to wonder why everything we build isn’t ICF.
The #1 reason more people aren’t building with ICF is that they don’t know the technology exists. The #2 reason is that, even though they know that the technology exists, they don’t understand it or the many advantages of ICF over conventional building. The #3 reason that more people aren’t building with ICF is they believe it costs much more than conventional building. It was once true that ICF could cost as much as 5% to 10% more than conventional building. However, with the rapid rise in lumber costs, ICF and wood-frame buildings are nearly equal in cost, and in many cases, ICF is slightly less in cost than conventional building. One thing is certain – once you calculate the operating savings of ICF into the equation, ICF is much less expensive than conventional building. And, those are savings that continue every day for the life of the home, which, since ICF homes are made of reinforced concrete, is also far superior to their conventional counterparts.
ICF forms are expanded polystyrene (EPS, which we know as “styrofoam”) blocks, as pictured above. The central cavity contains a plastic webbing system that performs two primary functions: it connects and secures the 2 ½” insulating panels together and contains “chairs” to accept the reinforcing rebar. The blocks stack like Legos, using the locking pins visible on the top of the forms. Into this cavity, which is available in widths from four to twelve inches, the concrete is poured, creating the finest, strongest, most energy-efficient building that money can buy.
ICF is an ingeniously simple building system that is far superior in every way to the conventional “stick building” method of construction we have been using for centuries.
Any home plan can be converted to ICF. If there is a particular wood-frame home plan that you are in love with and you just wish it was an ICF house, rest easy, it can be converted to ICF.
From a quick visual inspection, there is only one way to tell an ICF house from a conventional house – the exterior walls are thicker, which can be seen in the depth of the door and window jambs. Standard pre-hung doors and windows can still be used in an ICF house. Your builder will simply need to install jamb extensions to accommodate the extra wall thickness, a very simple matter.
Fireproof
In terms of fire resistance, an ICF home is far superior to a conventional wood-frame home, which is, basically, fuel. We can bore you with testing data and technical jargon, but nothing proves the point like photographic evidence! Can you spot the three ICF homes in the photo, below? Pretty easy, huh? Modern-day wildfires are destroying much of America, especially California. The following photo is of a San Diego, California suburb, which was ravaged by a wildfire in October, 2007.
Hurricane-Proof
Category 5 Hurricane Katrina, one of the most powerful hurricanes in history, flattened a neighborhood near Pass Christian, Mississippi. The only surviving home, still under construction, belonged to Scott Sundberg, an engineer and ICF advocate. Scott has since designed many ICF replacement homes for his neighbors, who lost everything during Katrina.
Rated to withstand winds of up to 250 miles per hour, even Category 5 hurricanes are no match for ICF, as evidenced in the FEMA photo of the Sundberg house, below.
Tornado-Proof
The mother of all storms, tornadoes pack four times the destructive energy of even the most powerful hurricane. Thus, if you can protect your family and your belongings from a tornado, then you have protected your family against any catastrophic storm event. As documented in the photo, below, a tornado can turn a subdivision into kindling in mere seconds. The lone survivor of this tornado was an ICF home under construction. The EF3 tornado that ripped through this neighborhood in Stoughton, Wisconsin on August 18, 2005 was so powerful that debris from the neighborhood was found 75 miles away. Yet, surrounded by the wreckage of its neighbors, this ICF house survived, losing only its windows, garage roof, and a small amount of roof sheathing.
Bug-Proof
Insects hate Styrofoam and they can’t bore through concrete. Where conventional, stick-built homes are a bug buffet, ICF homes are an exercise in frustration and starvation.
Energy Efficient
To set the backdrop for the following thermal study, consider this – in 2017, CLEB Laboratories was hired by the Insulating Concrete Forms Manufacturers Association to perform a study comparing the thermal performance of a 6-inch ICF wall to a 2”x6” conventional, stick-built wall. Keep in mind that nearly all stick-built homes in the United States are built with 2”x4” exterior wall construction, typically insulated with R-13 fiberglass batt insulation. Therefore, a 2”x6” stick-built wall insulated with R-19 fiberglass batt insulation would be considered super-insulated.
I have personal experience with 2”x6”/R-19 insulated exterior walls, as I built my own home in 1997 in the mountains of Virginia with 2”x6”/R-19 walls. At nearly 5,000 square feet, our electric bill never exceeded $200 and was typically around $150, even in the hottest part of summer. Winter was much less expensive as we heated with a heat pump, but used backup propane heat instead of the more expensive electric strip heaters in the heat pump for sub-freezing weather. Standard 2”x4”/R-13 exterior walls could not come close to that performance. Owners of 5,000 square foot ICF homes are reporting monthly heating and cooling bills of under $50 per month. Thus, a 6” ICF wall is vastly superior (60%) to a super-insulated (2”x6”/R-19) stick-built wall, as demonstrated in the following CLEB study. ~ Tony Blasioli, Deep Green Construction
THERMAL STUDY PROVES AN INSULATING CONCRETE FORM WALL CAN ACHIEVE UP TO 60% ENERGY SAVINGS AND 58% GREATER R-VALUE/RSI FOR HOME AND BUILDING OWNERS
The Insulating Concrete Forms Manufacturers Association (ICFMA) recently commissioned CLEB Laboratories (formerly known as Air-Ins Inc.) to conduct the first in a series of accredited whole wall thermal studies. This installment compared a 2” x 6” traditional insulated wood frame cavity wall to a standard 6 inch (150mm) core insulating concrete form (ICF) wall. The study was overwhelmingly revealing; confirming dramatically superior energy-efficiency performance and an overall better R-Value/RSI demonstrated by the ICF Wall assembly.For decades, the ICF Industry has been asked to provide definitive proof that thermal mass, the air-tightness and continuous insulation features of ICF walls deliver real, quantifiable benefits in terms of overall energy-savings and achieved R-Values/RSI. Many studies have been conducted in the past by the Portland Cement Association (PCA), the Canada Mortgage and Housing Corporation (CMHC) and the Department of Housing and Urban Development (HUD) all of which were either based on limited field comparisons or thermographic computer modeling. This is the first time a SCC & IAC Accredited, and Internationally recognized testing facility has been commissioned to evaluate a realistic side-by-side comparison of the two types of wall assemblies within a single study.
The test results confirm the following:
● The tested ICF wall assembly provided 58% better effective R-Value/RSI than the tested 2” x 6” wall assembly*● The tested ICF wall assembly generated up to 60% energy savings compared to the tested 2” x 6” wall assembly*● The measurable contributions of the ICF wall assembly’s thermal mass and the interior and exterior layers of continuous insulationWhat does this mean for consumers? Consider two typical homes, each with 2,000 square feet of wall area – one constructed in wood frame to permitted code*, the other constructed using ICF technology and subjecting both to the same test condition. When incorporating the average kWH value for all North America, this study indicates that in many climate zones that during the most extreme cold conditions an ICF wall can save between $140 and $190 per month in equivalent electrical consumption when compared to a traditionally constructed wood frame wall.
Quiet Living
Probably the least-expected but most-appreciated benefit of living in an ICF home is its sound attenuation quality (sound blocking or soundproofing). ICF walls block 75% or more of the normal, daily noise that penetrates a conventional, wood-frame wall. Hotels and theaters are raving over the soundproofing qualities of ICF.From ICF Builder Magazine: “Most ICFs with a six-inch concrete core (10- or 11-inch ICF wall) advertise STC ratings of 50 to 55. A Sound Transmission Class (STC) rating is a measure of how much sound travels from one side of the wall to the other, and is measured in decibels. Uninsulated 2×4 wood stud walls have an STC rating of about 33. Insulated with 3 ½ inches of fiberglass batt, the STC rating increases to near 38. The difference between an STC rating of 38 and 50 may not seem like much, but the decibel scale is logarithmic, meaning that 50 decibels is ten times as loud as 40 decibels. In real-world terms, only about one-quarter to one-eighth as much sound penetrates an ICF wall when compared to wood frame.”
ICFs are popular for hotel construction because they not only quiet exterior noise, but also eliminate noise between rooms.