Is There A Void Under Basement Floor
The void that you are feeling is normally caused by repeated heaving and deterioration of the basement floor slab over many years and some erosion of the sub slab soil.
Is there a void under basement floor. There may also be a storage floor called cellar below lower ground. When you drive over a void you will hear the shallowness of the space under the floor. In this situation the lower level is called lower ground the main floor is called upper ground and floors above it are numbered serially from 1. Garage floors show the least visible sign that there is a void under them.
You can usually tell there is a void under your garage floor by hearing it or feeling it. In that case the ground floor may be numbered 2 or higher. Installing a tile floor in all or part of your basement lets you have some fun with design while still quickly covering up existing concrete floors. You may also feel a slight tremor in the concrete as well.
Filling hollows under a concrete floor is done through a process called slabjacking. As the floor slab heaves slightly usually after repeated heavy rains or due to the spring thaw it can crack and will rarely recede all the way back to its original position. Small cracks may also be visible in.