We're building an earth sheltered house and after reading Rob Roy's "Earth Sheltered Houses" we want to insulate the Footings so that there won't be a condensation point. We want to use a rubble trench foundation so actually the footer would be a Grade Beam of concrete. I have probably a dozen books on building alternative houses and they either have diagrams of insulated footers OR Rubble trenches with no insulation around the bottom of the grade beam. So, I was thinking the insulation would be (for example) 2" along the southern wall, then what ever appropriate insulation for wrapping down the grade beam, under the grade beam with High compression strength blue board and back up the next side, then going under the floor. This would prevent thermal nose bleeds and a condensation point. I wonder if there is something I don't understand because I can't find anything on insulating below the grade beam when using rubble trench foundations? Here is a photo that will show the insulated footers and basically what we want to do with the grade beam.