Concrete driveways are usually made in sections. Quite often one or more of these sections will sink. In most cases this is due to a poor foundation, often exacerbated by poor water drainage. Concrete will also settle due to ground movement, heavy loads being placed on that section or a large vehicle being constantly driven or parked there.
These problems can be repaired.
First of all, any drainage or water problems need to be addressed. Water that flows toward the affected area or tends to pool on or close to the driveway, as well as water that may be coming from down spouts, will need to be channeled away. A good rule of thumb is for the water to be discharged approximately 15 feet away from the affected area.
Repairing
There are then two options for repairing the sunken slab.
The first choice is to remove the offending slab and pour new section of concrete. This involves a lot of work and takes time and tends to be expensive.
If there are concrete slabs adjacent to the one being repaired there will be a color difference between the new and the old concrete for quite a while.
The second choice is to have a concrete leveling company raise the slab by concrete lifting also known as “slab jacking”. This option is for slabs that are in good condition, slabs with numerous cracks or crumbling concrete cannot be lifted successfully. This lifting process involves drilling one or more small holes through the slab and a special concrete mix or crushed stone slurry is pumped under pressure into the area under the sunken slab.
As the new concrete is pumped in it raises the slab, returning it to its original height or position.
In most cases “slab jacking” is substantially cheaper that replacement and is done in a matter of hours.
NOTE: If the driveway settles or sinks with a slope that sends water toward the house, repairs must be undertaken immediately.
This type of excessive water flow will over time undermine the foundation of the home.
