Living Off Grid: Insulated Concrete Forms

| 3/30/2012 2:28:03 PM

A lot has been written about insulated concrete forms (ICFs) the past few years but mostly by manufacturers. We have two winters and one summer assembeld icfunder our belts now and it’s time to weigh in from a home owners point of view. Our temperature extremes run from 105F in the summer to -9F in the winter so we have a pretty good idea of how well this insulated building system has performed.

ICFs are usually 2’ long x 1’ high x 2 1/4” wide Expanded Polystyrene panels that are stackable and fit together like Legos. Plastic inserts hold the inside and outside panels together creating a space to be filled with concrete. The end result is a concrete wall with 2 ¼” insulation on both the inside and outside.

I’m not going to get into a lot of the selling points for ICFs in this blog. I’ll let the marketing departments and you or your contractor figure out what is and isn’t true about the so called advantages for using this system to build the walls of your home. I will say there are some advantages for sure but not all of their marketing claims are accurate. I would rather speak to my own experiences as a home owner and general contractor about the results we got in our home.

There is no question this is a good building system over all but as with any system there are items in both the Plus and the Minus columns. Those are what I would like to focus on for this article.


  • ICFs are fairly easy to work with and I would put more emphasis on labor than skill for their assembly. That’s good news for people who may want to do the work themselves or for contractors who are not familiar with this system. However, the marketing claims of “fast and easy erection” will only be realized by experienced installers.
  • ICFs are great for soundproofing. Our home is very quiet but keep in mind that part of the reason is the large amount of insulation we had blown in our attic, not just the ICF walls.
  • Properly braced they work just fine as concrete forms.
  • VOC free – no contaminants are released into the air we breathe inside our home and that is more important than ever before with the new energy codes that require our homes to be sealed.
  • More resistant to mold and rot than traditional wood framing
  • The insulation is more continuous than wood stud framing with insulation between the studs.
  • Electrical and plumbing turned out to work pretty well with this system.


8/11/2017 1:21:06 PM

Thank you for posting your findings , I will heed your advice in a upcoming build.

James Van Damme
4/15/2012 12:34:00 AM

Having the insulation on the inside makes the temp fluctuate more. This is good if you leave it unheated for hours as you go to work, perhaps. However, if you have a variable heat source like solar or wood, more heat storage is a good thing.

Tom H
4/14/2012 3:42:42 AM

i think the unsustainable ingredients could be offset by the significantly longer life span of this type of construction. Roman concrete structures not protected from the elements still stand thousands of years after construction. Science tells us foam and plastics will last eternity in a land fill. Imagine how much longer they will last under brick or concrete siding. The only structural thing to wear out in this type of construction should be the roof.

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