When Concrete Slab Meets Rotting Stump: Why Paving Over Stumps is Bad News
If you are planning to build over land that currently has—or soon will have—tree stumps, you might be wondering what you should do with the stumps. No matter what you build, be it a shed, a driveway or a garage, you are going to be laying concrete slab as the foundation. Cutting the stumps to ground level, then pouring the concrete over them would be a huge mistake.
Before you pour your concrete base, you should seriously consider having any stumps ground out. If you go ahead and pour the concrete anyway, as a contractor, you may be liable to pay for the repair of the structure when it fails in future. As a homeowner, you could be horrified to find the earth opening beneath your feet, releasing hordes of termites and ants.
Tree Stumps Cause the Ground to Settle
Large tree stumps may take around 10 years to fully decompose. However, as they decay under the soil, they cause the ground to settle. A concrete slab placed over a tree stump then, will eventually crack in several places, rendering the building, driveway or path that you construct useless.
No matter how tight your budget or how much pressure you are under to get the project under way, you would be wise to spend the time and money to grind out any stumps beforehand.
Tree Stumps Bring Termites
Another reason that building over rotting tree stumps is bad news is bugs. In Australia, you are never too far away from a hungry subterranean termite colony. Since termites are able to detect the presence of rotting wood via the way that it affects soil conditions, it may only be a matter of time before termites locate the stump under the concrete slab.
Combine termites with cracking and sinking concrete slab and you have a recipe for disaster.
Remove the Stumps and Compact the Soil
Although it will cost you more to hire someone to grind the stumps out, doing so will prevent the possibility of the ground swallowing up your construction project. Grind out any stumps, fill in the resulting cavities, and compact the ground where you plan to pour the concrete slab.
Buried tree debris such as tree stumps and branches can even cause sinkholes, like this one, that could put lives at risk. Don't cut corners by laying concrete over tree stumps. Hire a tree stump grinder and save yourself—and everyone else, the trouble that could result in a few years time.