The thickness of the basement floor in an average house can vary depending on several factors, including the building's location, local building codes, and construction methods. Typically, basement floors are constructed using concrete, and the thickness can range from 4 inches (about 10 centimeters) to 6 inches (about 15 centimeters).
In regions with colder climates, where frost heave is a concern, the basement floor may need to be thicker to provide added stability and prevent damage caused by freezing and thawing cycles. In such cases, the basement floor may be around 6 inches thick.
However, it's essential to note that the specific thickness of the basement floor can vary based on engineering considerations and the load-bearing requirements of the structure. For more accurate information about the basement floor thickness in a particular house, it's best to consult the original building plans, the contractor who constructed the house, or a structural engineer familiar with the property.