Although sink holes are the given names of many things in different areas of the country, here in metro Atlanta sink holes are technically just burial pits. For many years it was common practice for all types of debris to be buried instead of hauled off and disposed of. The one thing that most sink holes have in common is the presence of land clearing debris; that is stumps and brush. We have also discovered logs, construction debris, tires, and quite a few other things. We classify these holes in three different categories or types.

The first type of sink hole is what we call the development hole which is generally the largest and most expensive type to resolve. This type of burial pit was done during the original development of the neighborhoods. Often times this type of hole will exist on a property in the front yard and is typically parallel to the road or to a storm water easement. At this point in development the very largest equipment was on site and digging a large hole was very easy and inexpensive compared to hauling off the debris. Many of these holes cross property lines and some are extremely vast containing tremendous volumes of debris.

The second type of sink hole is what we call a lot clearing hole. This is by far the most common. Many neighborhoods in the Atlanta area which were developed and built between 1975 and 1991 have this type of burial pit at almost every house. This type of hole will generally be in a location that is consistent with it having been done at the same time as the foundation of the house was prepared. They can also be extremely large and deep and always contain land clearing debris. They are also often in the back yard where they are very hard to access with the necessary equipment.

The third type of hole is what we call a clean up hole. This type of hole was typically done when the lot was being cleaned up to prepare for landscaping near the end of construction. These holes are often times not very large having been done with just a small skid steer piece of equipment and contain construction debris along with some stumps and brush.

Today we have large equipment that can turn whole trees into wood chips and dispose of stumps in a matter of seconds. Also today is the widely used practice of hauling debris in temporary dumpsters which can carry more than twice as much debris than the dump trucks which were the common tool of hauling at that time. The smaller portions of trees were typically burnt when the season permitted and the large trees were used as pulp wood and lumber. The stumps were the one thing that they simply had no good way to get rid of back then. The typical landfills still today will not accept tree stumps as they are problematic in their operations. Nowadays we typically are hauling the debris either to private land fills that will accept that type of debris or to places where the debris is ground into mulch and utilized as mulch or composted into soil products. Those options simply did not exist during the time period when burying the land clearing debris was common place. It is becoming more and more expensive to dispose of our debris.

The impact to the existing yard can be vast. The proper manner to repair a sink hole involves digging out the same exact hole that was dug in the first place, removing any and all organic matter inclusive of tree debris and whatever else that may exist that can decompose and lose its mass. The process takes quite a bit of space to stage equipment, access the site to haul in and out and stage excavated materials to allow for the organic matter to be cleaned from the soil so that it can go back into the hole, and compacting the soil/fill materials back into the hole in a manner adequate to support the needs of what features will go back in place in the area of the sink hole. This varies a lot depending on whether the sink hole happens to be under a driveway or if it simply in an area of the landscape. The local lawn and landscape including patios, sidewalks, driveways, and the list goes on must be removed and replaced.

Sinkholes are generally easy to identify. They are typical to houses built during a certain period of time. They demonstrate certain characteristics. They can often times be detected with a soil probe. The debris in sink holes has not finished decomposing because it has been 20 years. For decomposition to occur it has to have the right mixture of moisture and air. These conditions may only occur a few weeks out of a given year. We have dug up pine straw that was still green after being buried for 20 or more years. It simply does not decompose without the right conditions.

I have heard many times from customers, “I had somebody add dirt to the sink hole last year and it just seemed to sink faster”. It didn’t seem to sink faster, it did sink faster. When dirt is added to the already sinking and settling area, this adds weight to an already failing situation and it will sink faster just about every time especially when it gets good and saturated during periods of wet weather.

Yes you can continue to add dirt over and over but the area will virtually never really finish settling. We have cleaned out sink holes where dirt had been added multiple times and others that had been in the ground for over 40 years and still the debris is in tact to a great extent.

We do not feel that any effort other than excavating and cleaning out the original hole is a valid repair. The common denominator is wood and wood will eventually decompose.