Crawl spaces can be tricky to master, so how do you know that yours is built correctly? Matt Risinger takes us a crawl space crash course, where we learn what to do, what not to do, and how to build them better. So a crawl space is a very tight and narrow area beneath a house, usually made obvious by a vent seen from the outside that is low to the ground. Common things you might find in a crawl space includes insulation, dust, mold, and vents. Risinger warns that thought these are extremely common, they're wildly inefficient, unnecessary, and downright gross to crawl into. What happens when air ducts run through a crawl space? Leaky air from a dusty, moldy, and moist area comes into your home, which is not ideal for air quality. Risinger poses a good question through, why not just build a basement? Where there is positive air quality and ducts that provide a clean and accessible place to maintain. Plenty of houses in the north do that and it works! Watch the full video to get the inside scoop on crawl spaces.