What are ICFs?
Insulated Concrete Forms are foam block systems (typically EPS) that when installed create a sandwich of foam and concrete. Standard ICFs have a layer of 2"-3" of foam on either side of a concrete core that is typically 4-6", some have even larger "concrete cores" available. This system creates the most energy efficient, structurally stable and sound resistant system on the market today. Other products may advertise a few of the qualities that ICFs offer, but none of those products have everything in one package that has been rigorously tested for many years and is approved by nearly all building, energy, green building and fire codes.
Energy Efficiency is paramount in today's society. Few products can compete with ICFs. A standard 2x4 wood stud wall with fiberglass batt insulation will have an advertised R-value of about 13-15. An ICF wall with 4" of concrete will perform as an R-32 to R-50 depending on the block system & climate. The reason it is noted as "perform as" is due to the fact that the comparison is not a true apples to apples comparison. A wood frame wall transfers hot/cold air at a different rate than the foam & concrete due to the Thermal Mass the concrete provides. R-value is the resistance of heat thru an object. EPS has a very high R-Value yet concrete has a very low R-Value. The difference is that fiberglass insulation resists the transfer of heat well, concrete absorbs and then dissipates that heat which creates the thermal mass. There is more that goes into the physics of how air transfers but that is the simplified version. A quick Google search will give you a more detailed analogy for those that would like additional technical data. Click on the “Images” button below to see diagrams for a comparison between a 2x4 frame wall and an ICF wall.
ICFs are more than just energy efficient. They are also in a league of their own when it comes to Natural Disasters. A 4" core ICF wall will have a fire resistance rating of 3-4 hours and is able to withstand a projectile traveling at over 200mph with little more than a dent (see video below). Earthquake damage can also can be minimized with the system. In addition, the blocks have been tested by the military for use in combat areas and have proven to be resistant after numerous ballistic tests. See our “Safe Design” page for more information about this.
ICF's are rapidly gaining popularity due to their structural integrity, ease of use and energy efficient design. RKD is recognized as an industry leader when it comes to designing structures with ICF systems. This experience will save you time and money during the construction process. Lower on this page there is an example of an ICF project and how we helped a client save over $70,000 on their home. With many different ICFs on the market, let us help you evaluate and decide which system will work best for your next project.
We specialize in ICF design
“Concrete homes will revolutionize American life. They will be fireproof, insect-proof & easy to clean. Extra stories could be added with a simple adjustment of the molding forms. Best of all, the $1,200-dollar houses will be cheap enough for even the poorest to afford.”
---Thomas Edison, 1906
ICFs can be one of the best choices to use when building any new structure, However, we all know that nothing is perfect. When you understand the challenges, the more likely it is that your project will succeed. One of the biggest challenges we see time after time is Structural Engineering. This happens when you have an engineer that is not familiar with the systems or one that is apprehensive to engineering anything but frame or masonry construction. When this occurs, they have a tendency to take on the attitude of if 1 is good, 5 is better. When this happens, it will cost YOU more money. The following is a real project we had and is a prime example of this happening.
A few years ago we had a potential client that discussed a new 3,500 square foot custom home with us and he wanted to use ICF. We explained the pros and cons and showed him different types of block systems. He chose a system he liked and we started the design. The design was very unique and it was for a lot that had some hillside challenges. When it was time, we recommended that he use an engineer that we have worked with many times on ICF projects. However, they had an engineer that was an acquaintance and wanted to use him instead – we explained the challenges but in the end we followed the adage "the customer is always right" and proceeded with their engineer. The plans and engineering was completed and the project went out for final bid & when the bids came in the project was over budget by nearly $75,000. The client was upset and wanted to kill the project. I persuaded him to give me a week to find out what the issue was.
I met with the general contractor and he stated that the majority of the overage was in the concrete and rebar per the engineering specifications. Upon learning this, I immediately had the original engineer I recommended review the plans. He came back with a solution – he would re-engineer the plans and if he didn’t shave at least $25,000 off the budget he wouldn’t charge for his services. The client agreed. The plans were engineered again then re-bid. The design of the home didn’t change and when the new bids came in, the reduction for the labor, concrete and steel was nearly $70,000. The owner further helped the budget by selecting less expensive finishes, cabinetry, plumbing and electrical fixtures – this added another $30,000 in reduced costs totaling $100,000 reduction from the original bid.
This proves how important having the right team is integral to any project. While a few dollars may be saved early on, it could result in thousands in unnecessary fees later on.