Hey, I'm Matt Blashaw. Today we’re talking about structures—specifically how homes are built and the materials that hold them together.
Most homes today are still framed with sticks—two-by-fours or two-by-sixes. It’s a tried-and-true method, but that's starting to change. More often now, you’ll see homes framed differently: full wall sections, complete with sheathing and insulation, all pieced together at once. At Premier Building Systems in Seattle, Washington, they custom-make these prefabricated panels, known as SIPs.
SIP stands for Structural Insulated Panel. It’s an alternative to traditional framing. Since SIPs are essentially pre-built wall sections, building a structure with them becomes incredibly fast. Literally, a couple of people can put up an entire house. It saves time, saves energy, and is a much greener solution. It’s definitely the next step beyond conventional framing.
While SIP framing does cost a bit more upfront, the energy savings over time are significant. You can expect 50–60% savings on your energy bills over the lifetime of the home. That’s real payback.
So, how are SIPs made? Let’s take a look.
At the core of a SIP is expanded polystyrene (EPS) foam. The specific foam used here has a one-pound density. It’s lightweight, strong, and extremely efficient. Unlike traditional fiberglass batt insulation, which traps a lot of air, SIPs eliminate almost all the air gaps inside the wall. That tight construction boosts energy performance.
Another advantage is that with SIPs, all the openings for wiring and electrical outlets are made at the factory. They use a hot wire cutter that works like a giant cheese wire to make precise cuts through the foam. After cutting, you can simply push the piece out, creating clean, ready-made channels for wiring.
Once the foam core is ready, it’s covered with OSB (Oriented Strand Board). While your local hardware store might carry small OSB sheets, Premier uses enormous, custom-cut pieces to ensure the wall strength remains consistent from top to bottom.
The next step is assembling the "sandwich"—combining the OSB skins, EPS foam, and a structural laminate using a strong adhesive. Once assembled, the panels are placed in a press for curing.
When the panels are complete, they’re marked according to architectural plans and cut to custom sizes. Interestingly, even with all the high-tech machinery, they still use a chainsaw for personalized cuts—because sometimes it’s simply the best method for the job. It also looks pretty cool!
For stock panel production, they use a CNC router inside a safety enclosure, since router bits can occasionally hit a hard spot and shatter—or at the very least, send foam bits flying everywhere.
Even though SIP panels are lightweight, they’re about 40% stronger than conventional lumber. Premier tests every batch by first checking the bond between the foam and OSB—making sure the glue holds tight—and then testing the foam's strength itself. In one test, the sample held until 93 pounds of pressure—well above the passing standard.
Although SIPs have been around for decades, they're just now starting to gain significant momentum in the building industry. The number of homes built with SIP panels has doubled since the late 1990s—and if Premier Building Systems has anything to say about it, that growth will only continue.
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