Slab vs. Crawlspaces
The Build Show Podcast - A podcast by Matt Risinger - Fridays

Matt does a deep dive into foundations and why one foundation might be a better choice than another, depending on your location.Many foundation styles came about because of frost-line differences. Northern builders might have a 3-foot frost line, which means it's necessary to dig below the frost line to avoid freeze-to-thaw issues in the wintertime. In other parts of the country, there might be a 1-foot frost line so a crawlspace makes the most sense. Finally, in the South and parts of the country with almost no freeze-to-thaw issues, slab on grade works great with a foundation embedded 12 - 18 inches into the existing soil. Matt considers how a foundation should be done when keeping ducts inside the conditioned space of a home. He focuses on crawlspaces versus slab on grade, with an emphasis on HVAC systems inside the conditioned envelope.