i’ve seen concrete molding made of a styrofoam material that you build the wall and just pour in the concrete. you don’t even remove them, they insulate the wall. been thinking about that for exterior walls. don’t know about it’s long term reliability
I haven’t heard of any long term reliability problems, but I suspect it is just about as reliable as a concrete foundation with rigid insulation put outside.
You are talking about ICF(Insulated Concrete Forms). The advantage of these is you can set up the forms yourself. At this point this construction method is more expensive the standard wood framing. Plus, you still need to frame out around the windows and the doors. The floors are still built conventionally. The only thing that would concern me in Maine is the potentially for carpenter ants to nest in the outer panel of foam insulation.
Keep in mind, heat rises from natural convection. Therefore, most of your heat loss is through your roof, windows and doors. It is not through the walls or foundation of the house. Frankly, a 2x4 framed wall with sprayed in closed cell foam insulation not only gives you plenty of R value, it also eliminates the need for a vapor
barrier. Other methods of construction from standard western framing lead to higher costs with your other contractors(plumbing and electrical).