What Causes an Uneven Driveway and Sidewalk?

Having an uneven driveway or sidewalk on your property can feel like a very small issue in comparison to some of the things that you need to deal with as a homeowner. Nonetheless, these are serious issues that can be caused by problems within the soil and the concrete itself. 

Soil-Based Issues 

When an otherwise healthy structure starts to sink, sag, or otherwise deteriorate without an obvious explanation, it is almost certain that the cause will be in the soil beneath it. There is no such thing as perfect soil, of course, but there is ideal soil. The ideal soil is stable, not too loose, and has good drainage capabilities. This kind of soil is well suited to supporting even heavy structures like large homes and commercial buildings. 

Expansive or marshy soil, however, is not likely to bear heavy weight as well. The changeable nature of this soil makes it unstable, and the marshy texture when it is saturated often leads to sinking and subsidence. Loose, weak soil, or heavily sandy soil, by contrast, is prone to erosion and washout and will leave voids under a structure when this happens. This can cause damage known as settlement. Either way, your driveway or sidewalk will become uneven and depressed when these issues take hold. 

Concrete Defects 

Concrete is really just a mix of cement, water, and sand that is malleable when wet but hard and brittle when dry. If there is an issue in the mix, or it is improperly laid, damage and cosmetic deformation are very common. Defects in the concrete itself can display themselves in a number of ways: spalling, flaking, pitting, cracking, and staining are all common. 

The most likely causes of an uneven driveway or sidewalk are a concrete mix that has too much water or sand (making it weaker and more prone to breakage) or improper deployment. If the concrete is disturbed once it has started to set, a process known as hard troweling, it can leave seams in the surface that are prone to breakage in certain places. If it is improperly cured, however, the driveway or sidewalk as a whole will be weak.