Rigid foam
Ensure the rigid foam insulation chosen is rated for below-grade use. Cover it with flashing as soon as possible to protect it from being damaged during construction.Foundation, p4
Rubble and Forms
Once the trench has been filled with stone, run a mechanical compactor over it several times to ensure settling. Next, two sets of grade beam forms are placed, one on the outside of the trench perimeter against the foam and the other on the inside perimeter. The spacing between these two forms (here 2X8s were used) should be the width of the bales plus the thickness of the foam insulation. In this case that sum was 20 inches. Ensure the top of the form boards are level with each other all around the foundation. Then use a handsaw to trim away any foamboard protruding above the forms. This will bring the foam and the forms to the same level and make screeding the foundation easy.
Trench being filled with "rubble", or, broken stone.
Once the trench is formed, calculate and mark the forms for placement of j-bolts, which will be set during the pour. These will secure the post bases as well as the bale curbs to the grade beam. This grade beam was designed to sit 2 inches above floor level. The 4X4 pressure treated bale curb then sits upon the grade beam raising the bales an additional 3 1/2 inches above the floor, for a total of 5 1/5 inches. This "doubling" of the raising of the level of the base of the bales above the floor is redundant and optional.