Prep the foundation

On a wood floor system:

1. Use a laser to level your floors before you set your first panels. A level floor allows the bottom edges of panel facings to fully bear on the floor while allowing vertical spline joints between panels to be flush to one another. Then spent on your floor prevents the telescoping of problems on up through the structure.
2. Glue and nail or screw your sole plates, holding them in from the outer edge of the deck 7/16" (typ.) so that the outer OSB facing of the SIP will be able to rest fully on the floor deck.
3. At corners, leave space between the intersecting plates to allow for the inner facing of one panel to slip down between the plates.

On a slab:

1. Again, use a laser to check your slab for level. If you have major problems with it, you'll have to put down a treated plate, level it, then glue and nail or screw a bottom plate to it. In fact, most applications are done this way, since the panels shouldn't rest directly on a slab. Alternative: place a 5-inch wide EPDM gasket on the slab, then install a bottom plate that isn't treated wood; this allows you to directly attach panels to that bottom plate.
2. Drill your plates for your anchor bolts; drill a 1-inch hole for countersinking the washer and nut down into the plate.
3. Your wood plate material in direct contact with the slab has to be either treated material or other type (e.g., redwood) suitable for direct contact with concrete. Rip some suitable material that will be wide enough to carry the full-width of the panel (e.g., 6.5 inches for a 6.5" panel).
4. Either apply an adhesive or slip a small EPDM gasket between the foundation and sole plate to seal against air leaks at this joint. Then tighten your bolts.

Leveling a rim joist for panel placement above. SIP houses require either a very level foundation (better) or considerable leveling of rim joise (okay) prior to placement of wall panels.