Bracing and top plates

After a few panels are up on one wall, you can attach a brace to help maintain level. The brace can be a standard 2x material, or you can a use an adjustable brace that, once attached with screws to the deck and wall, allows you to fine-tine for level by simply twisting the adjustment bar in or out. (Note: some SIP builders don't use any braces until they drop in their top plates.)

Top plates tie wall panels together.

Panels are connected at the top with long (12' to 16') top plates. Pick through your lumber pile for straight wood with no twists. Before attaching those plates, caulk both panel edges and the foam on the three sides where the 2x top plate will be slipped into place. Starting in one corner, place a plate in the tops of the panels such that the end of the plate falls at least two feet from the nearest panel joint; this helps keep the top of the wall straight and adds some strength at the panel joint.

Top plate is both glued and nailed to both panel edges and to top of headers.

On upper level floors, be sure to brace any gable-end walls. They could be blown off the roof during high winds and are susceptible to being bumped out of level during placement of beams and SIP roof panels.

Top plates will straighten out small ins and outs in this wall.