The Costs to Repair a Sinkhole

Formation

• Sinkholes form when sediment or rock moves into empty spaces created when water-soluble rock dissolves. Areas prone to sinkholes are those with thick carbonate deposits deep underground. Changes in weather and increased water usage due to urbanization and the formation of suburbs contribute to increased sinkhole formation.

Signs of a Sinkhole

• To minimize damage, it's necessary to detect sinkhole activity as soon as possible before the damage intensifies and costs increase significantly. Cracks are the most visible sign of damage and occur in floors, on walls or in pavement. They also form around the corners of windows and doors and, while they begin small, can spread to much larger proportions if ignored. Smaller signs, but equally important, are when doors and windows don't close properly anymore, which signify that the foundation may be shifting.

Testing

• Before you can take action to repair damages to your home, you must determine whether or not the damages are actually a result of a sinkhole. A professional geologist or engineer must come to the premises to perform tests including floor evaluations, ground penetration radar and standard penetration test borings. The average cost for an insurance company to perform the necessary tests was approximately $9,466, while the cost for individuals ranged from $8,061 to $10,116, at the time of publication.

Stabilization Techniques

• Geologists employ two primary techniques for stabilizing the area, grouting and underpinning. Grouting involves injecting a mixture of grout, which is various amounts of cement, sand, flyash and water, into the ground to stabilize the subsurface soils. In underpinning, steel pipes are drilled into the ground to stabilize the home's foundation. Both procedures are pricey, with the average cost for grouting a $150,000 home at $75,000 and underpinning costing an estimate of $35,000, at the time of publication.