Filling hollows under a concrete floor is done through a process called slabjacking.
Is there a void under basement floor.
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.
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.
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.
You may also feel a slight tremor in the concrete as well.
Small cracks may also be visible in.
Sometimes floor number 1 may be the lowest basement level.
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.
There may also be a storage floor called cellar below lower ground.
In that case the ground floor may be numbered 2 or higher.
Tile is available in many different sizes and styles and the price range is equally broad.
You can usually tell there is a void under your garage floor by hearing it or feeling it.