The customer asks you what to do. “Should I replace my concrete drive or can it be repaired and saved?” “My garage floor is severely pitted from salt damage and water. Can it once again be made to look new without having to dig out and replace the old floor?” “My parking lot has several prominent cracks. Can they be repaired and made to look aesthetically appealing or does the entire parking lot need to be replaced?” Depending on the project and a few variables, the answer, unfortunately, to these questions is often subjective.
“Ten years ago, replacing damaged concrete was often the preferred solution to repair,” relates Ardex Engineered Concrete Repair Systems Field Specialist Dennis Layne. “The ensuing decade, however, changed that. Economic realities made less-expensive repair options more attractive, as has the push for a more sustainable, greener building environment. Being able to repair existing concrete instead of removal and replacement seriously reduces the carbon footprint.”
He emphasizes that technology has kept pace, allowing repair products to be faster drying, stronger and more durable than their predecessors. “Contractors are becoming more savvy about these products and can offer repair solutions that might otherwise have been overlooked.”
Still, Layne says it comes down to the extent of damage and whether to repair or replace has to be determined case-by-case. His counterpart on the East Coast, Chuck Knight, agrees. “First, ask yourself if you can restore it to its original integrity. Consider how deteriorated the concrete actually is. Is there spalling, which refers to exposed aggregate on a concrete structure? If so, the concrete will likely have to be replaced. Is the damage caused by poor installation? Again, if the answer is yes, replacement is the best option. If it’s merely a worn or chipped surface, commonly referred to as delamination, then repair is a viable option.”
Concrete will eventually wear out, Layne adds. “Over time, the elements will cause the concrete to break down. In the north, especially, where there are wide temperature swings, cracking is more commonplace than in the Southwest. Pitting caused by salt is also prevalent in northern climates.”
The question is how much spalling is there? How much chipping is there? Is there a structural break? How much material is missing? If it’s too much, then the concrete will need to be replaced; repair would not be an option.
Matter of degrees
“A rule of thumb is if the repair requires more than 2 inches of material, then it would probably pay off to replace the concrete,” explains Joe Rizzo, regional manager for Oldcastle’s construction products division. “If it is less than that, there are a number of products on the market that can restore both the concrete’s structural integrity and aesthetic appeal.”
He continues, “But deterioration or extent of damage may not be the only criterion for making a decision. Clearance can be an issue if the repair involves pouring a layer of cement over the existing concrete. Time can be another consideration. How long can the structure be out of commission? Then there are aesthetics to consider, as well.”
Again, he notes that new products on the market can be real problem solvers, “New materials can be placed to a feather’s edge or be used to fill in pitted and spalled areas, and in both cases be ready to walk on within a matter of hours. Aesthetically speaking, new repair materials can be stenciled and stamped to incorporate a wide variety of designs, ultimately making a repair project look like a new pour. The repair material can be structural, as well. A load-bearing driveway, for example, can be repaired with cement-based material rated up to 10,000 psi.”