Concrete slabs, also known as slab-on-grade foundations, can be easily identified by ensuring your house does not have a crawl space. Slab-on-grade foundations are placed directly onto the soil and includes monolithic slabs, supported slabs, and floating slabs.
Raised foundations involve wood or metal beams, raised above the ground, that support the floor of the house. These foundations have crawl spaces which are accessed from the exterior of the home.
Crawl spaces can be identified by their small access doors and small vents. These can be found on the outside of your home near ground level. In addition, simple things like steps leading up to a house can prove that the house is raised.