What is an ICF?

ICF is an acronym for Insulating Concrete Form. An ICF block is typically 48” long by 16” high form with 2 ½” thick polystyrene walls and a 4” to 10” hollow cavity. Recycled plastic ties on 6, 8,or 12” centers hold the walls at the proper distance from each other and provide a surface to attach drywall and siding. The blocks interlock and are stacked in a manner similar to masonry, then reinforcing steel is placed inside the forms, and concrete is poured; leaving an extremely strong, airtight, very well insulated wall. Different forms have unique benefits, and we can pour walls from 4" to 24" thick concrete cores, and 5" to 16" total insulation.

There are too many to list, but some of the more significant benefits include: Up to 80% energy savings, significant noise reduction, excellent indoor air quality, very secure in severe weather, higher resale value, and long life expectancy. Call us for a further explanation of these benefits.

 This is a typical response which demonstrates a fundamental misunderstanding of ICF's and energy efficiency. Such an understanding does not fully take into account what makes an ICF so efficient.

1) Continuous insulation. Our continous insulation is at least 5" thick, not 1" over studs and headers which make up nearly 25% of a wall's surface area and have an r-value of around 3.

2) Low air infiltration. Most well built homes experience about .35 air changes per hour. The best stick builders I have heard of can get that number down to nearly .10 ach. That is, before the wood and caulk have been drying and shrinking for years. The best ICF home builders I have heard of can get that number down to .01 ach! That is 10x better than the best stick builders can do, and 35x better than most builders will ever accomplish! These are numbers from an energy rater. Air infiltration is arguably more important for comfort, health, and energy efficiency than the r-value of the insulation.

3) Thermal mass/thermal buffer. The thermal mass is the underdog of the bunch. This is called: "the ICF effect", and it cannot be measured by a HERS rating, an infrared scope, r-value, or any tool but the pocketbook. The concrete itself acts as a large heat sink to store and release energy as needed. It does an excellent job at evening out the highs and lows of the day. Thermal mass just laughs at wind chills.

An ICF home built by R-Value in cooperation with the Grand Valley School of Engineering has been outfitted with temperature sensors embedded in the concrete core for the full height of the home (basement + two stories above grade). Preliminary results show that the core temperature of the concrete significantly lags any change in outdoor temperature. We are talking days, not minutes! We also noted that the difference in the core temperature (averaged out over the basement and 2 above grade stories) of the concrete from the winter to the summer was only 23 degrees. The numbers don't lie. And there is another layer of foam yet before that 23 degree difference reaches the living environment! Thermal mass is a battery of energy that no one takes into account.

Doug Barr of Venture Design and Construction summed it up well for us. He recently built his own home with ICF's installed by R-Value. He was skeptical about how much better ICF's could be than sprayed foam, but after a winter in the home, his mind is made up. He explained to me that there are two rooms in his upstairs which are over garages, and thus stick framed with spray foam insulation; but there was: "a big difference between those rooms and the ICF portion of the home". To view his 2007 gas bill, click here and scroll down to the bottom.

The measured r-value of forms we normally use ranges from r-22 to r-24. We can use forms with up to r-68. This measurement does not take into account the continuous insulation, the thermal mass of the concrete, nor the reduction of air infiltration. When combined, these three elements contribute to a wall that performs better than a stud wall insulated to R-50 would! A 2x4 stud has an R-value of 3, and between the studs and headers, wood accounts for 25% of the wall area. This reduces the net R-value of a 2x4 wall from 13 to 9. 2x6 stud walls aren't any better. For a more in depth discussion click here.

 Since a completed ICF home doesn’t look any different than a wood framed house, you can’t see that it is built of ICF’s—you can only feel the difference! ICF’s are expanding rapidly, but in some communities people are less concerned with the environmental impact of their home, and more concerned about up-front costs. In other portions of the country, energy codes and other local conditions contribute to widespread use of ICF’s. Lubbock, Texas now uses only ICF’s for their low-income housing; realizing that while the home may cost slightly more to build, it is much less expensive to live in. Several developers across the nation are constructing communities entirely of ICF’s.

An ICF home can usually be built in the same amount of time as any other type of home. Commercial structures can often be built quicker, due to the combined steps of framing and insulating. Large sections of wall with few offsets and openings also contribute to the speed of building with ICF’s.

No, any blueprint will do; although we highly recommend one specifically drawn for ICF’s. See our “Building Process” page for more information.

 Costs vary widely depending on the specifics of the project. In some cases, ICF’s may be cheaper; but usually the project total will be around 7% higher than with stick framing. The walls themselves may run up to 20% higher than another system, but costs are recovered in insulating and moisture barriers, as well as smaller HVAC systems. Since the walls are only a small portion of the total cost, the total job costs are usually 6-7% higher.

If the entire home is constructed of ICF’s, the answer is a definite yes! The airtight nature of an all ICF home does not allow for natural ventilation of water vapor from breathing, cooking, bathing, and plants. Fresh air needs to be drawn in to replace the stale air, which often include gasses from drying paint, plastics, and other causes. A heat/energy recovery ventilator is the best method of ventilation, as the amount of air is controlled, and the incoming air is heated (or cooled) to match the ambient temperature of the home. Merely building a house with thousands of little leaks (like a wood-framed home) will allow fresh air in, but in uncontrollable amounts that must be heated or cooled at a cost to you!

We work as a subcontractor with you or your builder. We build anything concrete—footings, walls, floors, sidewalks, patterned concrete, etc.; but our specialty is ICF walls and Lite-Deck floors. We meet with you to determine your needs and desires, select an appropriate form, and get comfortable with each other. We also generate heat loss calculations to show you just how much you will save, and we work closely with your subs to educate them and make the installation as smooth as possible.

Owner-built homes are becoming quite common, and they can be done with ICF homes as well. We stongly recommend against this, as there is a lot to learn, and only one chance to get it right. There are many horror stories out there about ICF walls being out of level, crooked, and bowed. These come from inexperienced people setting and pouring the walls.

We have found that knowing the ins and outs of the ICF building process allows us to save money in certain areas, as well as avoiding problems. In addition, we purchase the concrete, rod, and forms at a significantly lower cost than a homeowner or builder trying ICF's for the first time could, due to our volume; thus making our installed cost similiar to a do-it-yourselfer.

Hiring a professional installer gives your home insurance coverage while we are working on your site, moves the project along much more quickly, reduces quality problems, and gives you a warranty for your peace of mind. A professional such as R-Value also makes getting permits and inspections easier, and construction loans are not considered as risky when professionals are hired. Installed costs for an expert are in line with do-it-yourself installed costs. With all of these reasons, why wouldn't you use a pro?

That depends. Technically if the area is not “habitable” space, it does not need a thermal barrier; but the authority for this decision rests on the local inspector. R-Value Concrete Structures LLC can work with your inspector to provide the documentation he/she may require. R-Value has published a bulletin addressing this issue which you may find quite helpful.

Yes, any finish you can think of can be used with ICF’s, there are no limitations; and in fact, a stucco, TAFS, or EIFS finish is less expensive to apply over an ICF wall.

Yes, a company that specializes in cutting concrete can be called to cut a rough opening in, then treated lumber is fastened to the wall, and a window is fastened to the lumber. The cost and amount of disruption are similar to adding a window to a wood framed structure.

Yes, there is no reason ICF’s would be a problem in either of these cases. And they do make sense even for small additions, because they save so much in energy costs.

R-Value can apply cement-based product is applied with a trowel over fiberglass mesh which is attached to the ICF wall. This gives it protection from stones, water, and other hazards. Sometimes builders install a wide piece of fiber-cement trim board at ground level to dress up this area.

We can use nearly any block made, but have found that some are more trouble than they are worth. We have installed Amvic, Reward, Logix, BuildBlock, Nudura, Standard, and Phoenix; and have relationships with Fox, TF system, Greenblock, and others. Since we are not affiliated with only one block manufacturer, we can objectively assist you in finding the best block to suit your needs.

Lite-deck is a polystyrene form that is used to form concrete floors and decks. It can be designed to clear 40’ spans, and support nearly any amount of weight. It is most popular for two level garages, where a precast concrete floor would otherwise be used. Advantages include: easy attachment of ceiling finishes, simplicity of electrical and plumbing installation, easily accommodates floor drains and slopes, and, due to its nominal R-30 rating, perfect for radiant heat.

Yes! An energy efficient mortgage (EEM) is an excellent way to take advantage of the energy savings of an ICF home. For some homebuyers, it may be the only way they can afford an ICF home, since it really levels out the playing field. We have information on a local lender listed on our Find a Builder page; and an internet search will turn up a lot of information.