Local Home Builders Association Expo is going on and some great information there. But now have questions.
I am looking at to start to build a house in 3 to 6 months. My original plans were to have ICF foundation and basement walls (walkout) and then have 2x6 exterior walls on floor above basement with icyene insulation.
When talking with different insulation installers at different times they both stated that one way to save money would be to go with 2x4 walls. Reason being that the R Value is at 3 to 3.5 inches. There is no gain until you get to about 8 inches in thickness. They both said I would be wasting money filling the entire 2x6 wall with foam and said that only 3.5 inches would suffice. But they also both said that they would suggest putting in at least 8 inches in the roof. They also said that unless I want the protection from a tornado they suggest in saving the money and use convention construction on the basement level and spray insulation.
Now the ICF contractors I spoke with said to do the entire exterior walls all the way to roof but they said average of 4% increase in cost. It would have added safety, quiet, and lower utility bills.
I want as much efficienty as possible but the best cost factor just like everyone one else.