Concrete is among the most widespread building materials in the world. Its low cost and easy customization make it an extremely versatile component of many structures. Despite its strength and durability, however, concrete isn't invincible. There are a number of issues that can affect concrete, making it less stable and more prone to structural failure. And while it can be inexpensive to mix and pour, fixing or replacing a concrete surface or structure could be expensive. According to Angie's List, the average 750-square-foot residential concrete driveway would cost about $1,700 to resurface. With special features added on, costs can easily rise to $3,000 and above.
Even if you might be tempted to throw in the towel and completely replace an old, cracked concrete driveway, sidewalk or wall, it might be useful to have a professional home inspection to determine the cause of the damage because a home inspector may be able to recommend the best method of repair.
Concrete is actually a general term that can describe a few different building materials. In all instances, it is composed of a coarse, rock-based substance called an "aggregate," along with a fluid adhesive material like lime. It is mixed as a thick liquid before being poured into a mold, allowing it to take any number of shapes and sizes.
Like any other building material, concrete will eventually break down for one reason or another. Fortunately, a trained inspector can spot if your concrete is experiencing issues and suggest the proper method of treatment.
Common reasons for cracks
Ingredients: The binder or aggregate used in the concrete can impact how it tends to degrade. According to the International Association of Certified Home Inspectors, among the most common binders is Portland cement. Without a certain additive, Portland cement could slowly form holes as it gets exposed to moisture. These holes allow more moisture and potentially chemicals to enter the concrete, breaking it down further.
Water: A key ingredient in concrete is water. The ratio of water-to-cement paste varies from 25 percent up to 45 percent. More water content in the cement allows for the final concrete product to be more easily maleable when poured. However, more water in the cement also makes the concrete more able to accept water even after it dries. According to InterNACHI, porous concrete can lead to small "capillary" cracks forming as the water evaporates repeatedly. This makes damage from ice and chemicals more likely.
Mix, quality and other factors: How the concrete is mixed, poured and handled can have just as much impact on its quality as what it's made out of. InterNACHI noted that even weather conditions like temperature, humidity and cloud cover can affect drying and thus ultimate durability.
When the concrete is poured or applied, reinforcing steel must be adequately covered. InterNACHI noted that this is a common issue regarding concrete quality. The concrete must also be properly layered and set into place with a vibration mechanism. Failure to perform these steps carefully will result in a honeycomb pattern forming in the concrete, according to InterNACHI, which will cause it to break down faster.
Ultimately, every step of the process counts when creating and applying concrete to a surface. Homeowners or those renovating should ensure they take steps to research and find the best concrete specialists for their area and budget. It's also important to care for concrete surfaces by keeping them clean and preventing the buildup of standing water whenever possible.