What is a Sinkhole?
Sinkholes — sunken layers in the land caused by changes in material beneath the land’s surface — are a serious problem in some areas. Particularly in Georgia and Florida, sink holes are a common landscape blight.
Though most are only 10 to 12 feet in diameter, sink holes have been known to expand to hundreds of feet in diameter and can appear with disturbing speed. Depending on the cause they can range from small, easily repairable nuisances to major landscaping problems.
What Causes Sinkholes?
Most sinkholes occur where debris such as trash, stumps, tree branches and other building materials were buried during a construction project. Over time, the debris decays, leaving an empty space under the ground.
Hidden under a layer of soil, this space goes unnoticed until it finally caves in, leaving in a sunken area in the landscape. Less commonly, sinkholes may be caused by broken water pipes or cisterns.
Georgia and Florida Sink holes
Georgia and Florida sinkholes have their own unique cause: sinkholes in this area are brought on by the slow, natural process of erosion in the area’s underground limestone caves. Although the decay happens over thousands of years, when it reaches a critical level, land within a few hundred feet above the limestone collapses — sometimes literally overnight.
How to Recognize a Sinkholes
If you discover that a section of your landscape is sinking, determining the cause is the first step towards repairing it. Avoid walking onto the sunken area. From the stable edge of the sinkhole, use a shovel or stick to dig through the surface layer. If you continue to hit earth, rather than a hollow space, the problem is likely due to normal settling of the ground, rather than a sinkhole. If you can dig through, inspect the inside with a flashlight. See a bunch of old building materials or decaying branches? Then what is have is a construction sinkhole that you’ll probably be able to take care of yourself. If you see standing water or a pipe, though, the sinking land may be related to a broken sewer line. (Needless to say, in this case, contact the county or city water department immediately.)
How to Repair a Sinkhole
Different types of sinkholes require different treatments. Most small construction sink holes can be repaired without a professional, while other types require a landscape contractor.
Test the hole with a stick or garden tool to determine if the bottom and sides are solid. If they are, you’ll be able to fill the hole yourself by simply adding layers of soil, a foot at a time, and packing each layer down firmly as you fill the hole. Once the area is refilled, you can safely plant on it again.
If you can push through the sides or bottom seem soft and ready to give way, you’ll be safer calling in a contractor. The sinkhole may be much deeper than you think and you risk injuring yourself or doing extensive damage to your lawn and garden if you repair the sinkhole incorrectly.
Is it necessary to repair a sinkhole?
We strongly recommend home owners repair sinkholes by excavating and removing all the decay material found in the hole. Some municipalities, like Roswell city, are very strict and are now enforcing covering the sink hole as well as requiring digging out to remove all the debris.
My yard is settling…do I have a sinkhole?
Maybe. But a number of other factors can cause holes, depressions or subsidence of the ground surface. Expansive clay layers in the earth may shrink upon drying, buried organic material, poorly-compacted soil after excavation work, buried trash or logs and broken pipes all may cause depressions to form at the ground surface. These settling events, when not verified as true sinkholes by professionals, are collectively called “subsidence incidents“. If the settling is affecting a dwelling, further testing by a licensed engineer with a professional geologist on staff or a professional geology firm may be in order. Property insurance may pay for testing, but in many cases insurance may not cover damage from settling due to causes other than sinkholes.
I think I have a sinkhole. What should I do?
Small holes often require only filling with clean sand or soil. If the hole is under or very near a structure or swimming pool, your property owner’s insurance may cover assessment and repair. Mark and secure the hole and keep children and pets away. If the hole is directly impacting a house, and sinking, sagging, or cracking walls are apparent, stay out of the dwelling. Call us immediately!
Do I need a permit to fill a sinkhole?
In general no permit is needed to fill a new dry sinkhole.
How long does it take for a sinkhole to stop growing?
When an underground cavity enlarges to the point that its ceiling can no longer support the weight of overlying sediments, the earth suddenly collapses into the cavity. A circular hole typically forms and grows over a period of minutes to hours. Slumping of the sediments along the sides of the sinkhole may take approximately a day’s time to stop. Erosion of the edge of the sinkhole may continue for several days, and heavy rainfall can prolong the stabilization. In the less catastrophic cover subsidence type of sinkhole, sediments slowly settle into underground voids in the bedrock. A bowl-shaped depression forms at the surface, typically over longer periods of time (sometimes as long as years).
Can a retaining wall improve my property value?
Block walls can improve the value of your home by adding a sense of prestige. If you are looking to accent your landscaping designs, make grade changes, or solve erosion control problems, we are qualified to install any different styles of block and colors to suit your vision.
When is a Retaining wall permit required?
Retaining walls over four feet high must be engineered and permitted. Walls greater than 6-feet require Certification from Engineer that the wall was constructed in accordance with the approved construction plans