Episode 2 of Build Science™ 401 walks through how to design a high-performance foundation by keeping the four control layers—water, air, vapor, and thermal—continuous and aligned, using a real-world ICF foundation as the example. Matt Risinger and Steve Baczek break down how components like insulated concrete forms, Glavel, drainage layers, and compatible waterproofing work together to manage moisture, air leakage, and heat flow below grade. They challenge common myths around vapor barriers, slab drying, and air sealing under slabs, emphasizing risk management and real-world performance over theory. Ultimately, Matt & Steve emphasize while details may vary, building science fundamentals stay the same, and systems that do multiple jobs tend to be more resilient and efficient.