Driveways must feature a slight slope to allow water to drain off and away from the concrete. If your property contains a steep slope, however, your driveway may experience problems associated with a grade that is higher than normal. Soil beneath a steep driveway can become unstable and erode or shift. When this occurs, the concrete can sink or experience cracks.

Sometimes the soil of a slope beneath the concrete, or subgrade, can make concrete sink and crack due to poor compaction during construction. Other times a contractor uses the wrong materials. For example, crushed stone or other granular materials work best to stabilize soft areas of subgrade while the addition of a stabilizing material like lime reduces permeability and the tendency of expansive soil to swell.

Our area of North Carolina experiences many rainy days per year, with periodic heavy rain from hurricanes in late summer and fall. Runoff from precipitation, sprinklers, and other sources of water can hurt a concrete driveway over time. Often portions of a driveway will sink or crack when water cannot drain away from the concrete, or when it percolates through to the foundation.

Water that remains trapped beneath concrete eventually erodes the foundation and causes portions to sink. Additionally, runoff water that puddles on the surface of concrete acts similarly. Poor grading and pits or potholes encourage standing water to deteriorate a foundation as well.

Ask your concrete contractor about their warranty policy in regards to damage from water runoff, especially under circumstances where they fail to grade properly or install sufficient subbase.

Part of a lush landscape includes shrubs, plants, grass, and trees. When tree roots encroach upon your driveway, however, the proximity of strong roots can cause damage. Thick roots force concrete upward and cause buckling, heaving, and large cracks.

Existing trees that hurt a driveway will continue to grow and spread damage. Often the best solution to prevent more damage is to grind down the visible roots or remove the tree entirely. Both remedies can be costly and time-consuming but necessary if you want a pristine driveway.

You can prevent tree root damage too when you plan future tree sites with care. Plant new trees far away from your driveway, especially large shade tree species. If you must have trees near your concrete driveway, keep them at least six feet away, where tree roots tend to be smaller and weaker. Then, choose tree species that won't get as tall when mature.