There are several parts of our workshop where strawbales don't make sense for insulation—mainly places where we have 2x4 framed walls (e.g. the pony wall and the west wall). So, we hired the same company that insulated our cottage's pony wall to spray foam these. Even though these parts of the building are only 3.5" thick, they'll be somewhere between R18 and R24. Pretty cool! (...in summer. Warm in winter!)