In this third episode of the Foundation section of Build Science 301, Matt and Steve explore two “specialty” foundation systems: pier-supported floors and insulated concrete forms (ICFs). Though sometimes misunderstood, these systems offer smart solutions for challenging sites—like steep slopes and bulk water exposure—while posing unique performance and detailing considerations. Learn how to manage air and thermal control with pier floors, protect ICF foundations properly, and use site excavation clues to guide your water management strategy. If you've ever been hesitant about “unusual” foundations, this episode lowers the learning curve with real-world insights and proven techniques.