Here is a link you might find helpful.
http://www.forms.org/content.cfm?act=constructioncostHow much does an ICF house cost?
Houses built by experienced contractors cost about .5-4% more than wood frame houses of the same design.
Typical new U.S. homes cost $60-100 per square foot. Building walls of ICFs adds $1.00-$4.00 to this figure. But since ICF houses are more energy-efficient, the heating and cooling equipment can be smaller than in a frame house. This can cut the cost of the final house by an estimated $.75 per square foot. So the net extra cost is about $.25-$3.25.
Why is there such a big range in the costs?
The cost of using any construction product is pushed up or down by dozens of factors that change from house to house. But for experienced crews, the major influences on ICF cost are fairly predictable.
To begin you can assume that your house will cost $2.00 more per square foot to build with ICFs. This is near the middle of the historical range. Then adjust this cost premium according to the particular features of your construction project:
If you can buy ICF forms for $2.00 per square foot Subtract $.50
If you buy ICF forms for $3.00 per square foot Add $.50
If you will finish the exterior with stucco Subtract $.50
If you will finish the exterior with individual shingles Add $.30
If you will build the house to resist high winds Subtract $.50
If you will build the house to resist earthquake Add $.15
If the cost of wood rises to $4 per stud Subtract $.20
If the cost of wood falls to $2.25 per stud Add $.12
If you can buy concrete for $35 per cubic yard Subtract $.16
If you buy concrete for $65 per cubic yard Add $.13
If your design includes cantilevered floors or walls Consult an engineer