In this particular application, here’s what we’re looking at: there’s a joist sitting on top of the mud sill, with the rim board, subfloor, and bottom plate all layered above it. The bottom plate is the part that gets encapsulated by the SIP panel.
If you look closely, you’ll see that the SIP panel skins extend down on each side of the bottom plate, flush with both the finished floor and the exterior sheathing of the structure. This is important because, in SIP construction, the skins take the load—they bear the gravity loads, shear loads, and more. That’s different from traditional stick framing, where the sheathing usually just hangs past and isn’t structural.
You’ll also notice that the foundation wall continues upward, allowing the joists to be hung from the plate line. In this setup, there are two treated plates stacked. The first treated plate supports the top-flange joist hangers, and the second one provides space to clear the bolts, like the J-bolts anchoring the framing to the foundation. Then, as before, you have your finished floor sitting above and your bottom plate ready for setting the wall panel.
When installing the SIPs, the crew measures where the vertical chases are located and marks them out on the plate line before drilling through. This allows electricians to run wiring up into the vertical chase—from underneath if there's a crawl space, or from above if it’s a two-story structure (bringing wires down through the floor joist and rim area into the top of the wall panel).
All of these chase locations are pre-drilled based on careful measuring from the SIP panels themselves or by reviewing the shop drawings to ensure accuracy.
Finally, the crew preps the SIP panel for installation using a spline-style connection. Earlier, we looked at a lumber connection, but here they’re prepping specifically for spline installation, which helps tie the panels together securely.