Gone are the days when condominium living was strictly for empty-nesters. Today, not only is the older population seeking the conveniences that condominium living provides, but young professionals also recognize the value of such facilities. According to the National Association of Realtors, sales of existing condos and co-ops have dramatically increased in recent years. In 2001, there were approximately 746,000 condominiums and co-ops sold. In 2003, this number jumped to 940,000. This marks an increase of more than 26 percent. Such data demonstrates the growth that the condominium market is experiencing. However, to ensure that owners receive value on their investment, condominium facility and property managers, as well as association boards, must allocate proper funds to the repair and upkeep of the units. One such item is the repair of concrete, particularly in balconies. By arming yourself with the basics of concrete repair, you can ensure that your facility receives the proper maintenance and your community remains attractive for future buyers.
Basics of Concrete Repair
The key to understanding the best repair solution for your facility is knowledge about the basics of concrete repair. In today's lexicon, the word "concrete" has come to symbolize strength and stability. Yet, for all its seeming permanence, concrete comes under attack from both natural and man-made forces almost from the time it is first formed and poured. The relative rate of degradation resulting from these assaults depends on a wide variety of factors of which only some are controllable. This fundamental knowledge will provide the foundation for recognizing when your facility is need of repair.
There are a number of variables that can affect the strength and integrity of concrete. For example, too much water, or water with impurities or chemical compounds beyond certain thresholds, will affect its durability. In addition the relative size and coarseness of the aggregates plays a role in the size and thickness of the structural components in which they are to be used.
At some point, as the concrete hardens and sets, the material will have hardened to a stage where hydration transitions to a process called "curing." In its simplest terms, curing is the rate at which the concrete gives up its moisture content and, thus, hydrates. Proper curing is absolutely critical to the integrity and strength of concrete. According to the Portland Cement Association, "Curing has a strong influence on the properties of hardened concrete such as its durability, strength, watertightness, abrasion resistance, volume stability, and resistance to freezing and thawing."
Most, if not all, of the factors listed above, play critical inter-related roles in the degradation of concrete. Obviously, it is impossible for today's engineering team to know how the concrete of an infrastructure was mixed, poured, and cured. However, the knowledge of the basic properties of concrete will aid in determining the best repair strategies.
Conversely, man-made forces affecting degradation are often controllable and fall into two general categories: those that cause deterioration because the marketplace was less knowledgeable about concrete 40 years ago; and those that cause degradation due to obvious design deficiencies or subsequent neglect. For instance, if acid were allowed to leak into the soil around a supporting pier, it could degrade the concrete. Similarly, if chemicals or some other mildly aggressive agents spilled onto a concrete surface and were not properly cleaned up in a timely manner, they could cause degradation or exacerbate an already existing problem. High-pressure or high-temperature venting and physical forces such as flexing, overloading, or repeated impacts are other potential contributors to the deterioration process.
Foremost among all causes of concrete degradation is the internal damage caused by the corrosion of the embedded reinforcing steel, which falls under the man-made category. In addition to deterioration of the steel itself, the corrosion also affects the concrete surrounding it, which results in cracking, delamination and spalling. Since virtually all of the concrete found in structures is steel-reinforced, this is a widespread problem. The science surrounding this phenomenon is still evolving. However, it is critical to learn from previous misconceptions to avoid these same pitfalls in the repair process.
Unfortunately, the methods in which concrete deterioration manifests itself typically do not indicate the true severity of the problem. Virtually from day one, concrete comes under attack from environmental factors, and the deterioration process is both insidious and continuous. The first small crack in its protective lining invites intrusion by moisture or corrosive agents. Eventually and inevitably, the outward symptoms of scaling, cracking and spalling gradually begin to appear. Without exception, concrete degradation problems do exist to some degree. The only variables are how and when they will manifest themselves.
Heightened Deterioration
One area that frequently experiences deterioration is concrete balconies, especially in the Southeast. With an average rainfall of more than 60 inches per year that has high chloride content, the climate in Florida aggressively attacks steel reinforced materials. Typically wind-driven, the rain does not fall straight down; rather, it is blown onto exterior balconies and walkways. Further, many balconies are now carpeted, which creates problems for the concrete since carpet can retain the moisture and the inherent salts that eventually impact the steel and begin the deterioration process. Water, steel and salt create a simple battery and the steel acts as the anode that sacrifices itself in a galvanic reaction. This reaction changes iron to iron oxide and the larger molecule requires more space. Therefore, the steel expands and blows the concrete cover off, allowing for further water intrusion and acceleration of the deterioration process.
Creating a Successful Repair
Defined in the simplest possible terms, concrete repair integrates new materials with existing materials to form a composite structure that can withstand environmental conditions and operational processes, while at the same time providing extended service life. Obviously in this market, a successful repair undertaking is also one in which disruption to residents is minimized while the repairs are taking place.
In the condominium market, the need for concrete repair is typically first witnessed by the maintenance personnel. Cracking or spalling may be visually apparent, and the maintenance team alerts the property manager. Then, the property manager notifies the condominium board. Based on preliminary information from the property manager, the board then decides whether to hire a consulting engineer to assess the problem. The consulting engineer serves as an owner representative and provides an unbiased opinion about the problem. After the consulting engineer's review, he or she lists the items that need to be completed by developing a scope of work. The next step is to hire a contractor to perform the repairs that the engineer has outlined. A typical team for a condominium repair project includes the owner, contractor, owner representative (consulting engineer) and a material representative.
To ensure that the project is successful and everyone is working towards the same goal, it is important to have the entire team involved from project onset. Once the decision is made to undertake a concrete repair project, the next step involves examining repair strategies and selecting the best course of action.
Today's available technologies are advanced far beyond the simple concrete patch and a range of solutions can be utilized to implement an effective concrete repair program.
A basic understanding of these options - surface repair, protection, stabilization, strengthening and waterproofing - will allow selection of the best program for your condominium community. A concrete repair specialist also can help determine both the underlying cause of the problem and the optimal solution.