ICF stands for Insulating Concrete Form and are used to build structures of any size.
Basically, ICFs are molds. The builder will stack and shape these forms to create a shell and then that shell is filled with concrete. This technique was invented after World War II as an inexpensive and durable way to repair damaged structures. ICFs would take their next leap in the 1960s with the use of modern foam plastics. And it wouldn't be until the late seventies that ICFs would be recognized in building codes.
However, most people will give you a funny look if you told them that you would be using what is essentially "Styrofoam" to build their home. Actually, Styrofoam is just a brand of polystyrene foam and the type of polystyrene used is an expanded form with various advantage over your average Styrofoam plate.
Enough science and history, let's dive into some advantages of ICFs.