I plan on building a home with a basement. Based on Oregon insulation requirements, what is the cheapest method?
In meeting Oregon’s (or Washington’s) energy code we have used three methods. They are: 1) a concrete wall with foam insulation on the exterior conc. wall; 2) a conc. wall with a standard 2×4 stud wall stepped 2″ off the interior conc. wall with R-21 (OR) or R-19 (WA) batt insulation; 3) the use of foam block forms filled with concrete that give typically give an R value of around 22 depending on the specific foam block company.
