Hi, Given a typical ICF corner wall (6" core), how close can a window be installed to the corner? Is 4" too close?

According to the prescriptive method yes. However, with a little engineering assistance you can easily accomplish- even to the point of having all glass window corners. Regards

Where are you building? Canada's Building Code doesn't allow openings in ICF walls to occur withing 1200mm (4 feet) of a corner. It is a terribly restrictive part of NBC. Similar restrictions are not placed on design if building under the umbrella of an ICF manufacturers design (or get an engineer to review/approve your plans).

Thanks for all the answers.

The home will be in S. California. It will be contemporary in style so no trim, casing around the window opening. The window in question is floor to ceiling is 12' x 4'. I was just wondering how much room i would need from the corner.

I recommend you download and read the prescriptive method. Also many of the block manufacturers have their own engineering documents that may shed some light on things. If your desires fall outside what is allowed by either of these documents, you can alter the design or hire an engineer. It might take a while to read and understand these, but they are written in laymen's terms. You won't regret it.

Thanks rvalue.