One of the greatest benefits of precast concrete is its durability. Precast is resistant to corrosion, impact, air penetration, water penetration, and acid. It can resist the accumulation of dust, withstand freeze-thaw cycles, and prevent surface voids. You don’t have to worry about insect damage, termites, mold, or decay, either. It can easily withstand more wear and tear from weathering than most other building materials, as well as damage from natural disasters.
In one word, you could say that precast concrete is tough.
That’s not to say that it will never require any maintenance or repairs, however. After all, every building must endure some environmental exposure. While you’ll have to worry considerably less about maintaining precast concrete, there are some things you should know to ensure it lasts for decades, if not centuries.
Conduct Visual Inspections
Conducting regular visual inspections of your precast concrete products or buildings can help you catch maintenance issues early on and fix them to ensure continued performance.
Visual inspections are recommended on an annual basis. During the inspection, pay attention to surface appearance, caulked joints, and connections. Document all signs of chips, fractures, and deterioration for further monitoring or repairs.
Prevent Common Sources of Staining
A concrete surface can be stained by biological sources, the leaching of chemicals from other building materials nearby, and atmospheric pollution. Common sources of staining include leakage from mechanical units, run-off water from cleaning, salt used for snow removal, and exhaust or discharge from mechanical vents.
While staining will not affect the integrity of the concrete, it will reduce its aesthetic appeal. Conduct visual inspections regularly and clean the surface when discolouration occurs to prevent staining.
Stubborn stains can be removed using a mild trisodium phosphate solution.
Cleaning Precast Concrete
Precast surfaces without special finishes should be cleaned using clean water only. This will prevent the detergents and chemicals in the washwater from being absorbed by the material. You can pressure wash exterior surfaces.
If the building hasn’t been cleaned in years or has been subjected to harsh weather conditions, a grit-type cleaner or acidic treatment can be applied.
For precast surfaces with sealers, finishes, or pigments, test your cleaning method in a small, inconspicuous area before starting work on the entire area.
Although rare, fractures may occur over the service life of a precast concrete product, particularly when it comes to precast panels. This can occur due to panels bearing on one another (known as long-term creep of the building structure), thermal movement, or the movement of the panel system.
Note the size of the crack width, so you can determine whether it widens or lengthens over time. In many cases, when the cracks do not progress, all that will be required to repair a fracture is to seal it immediately to prevent any further damage caused by ingress of water. You may also want to consider reducing the force that caused the fracture by sawing or grinding the panel joint.
If it’s determined that significant damage has already occurred, the crack is deep, or the crack is moving and getting larger, the panel should be replaced as a long-term fix.
Grind or Reshape to Repair Chipping
It’s common for concrete products to chip at exposed corners. This is a minor aesthetic concern that does not have an impact on the product’s performance or integrity.
If you prefer to repair chipping, you can grind the concrete or reshape it with a patching compound where it has been damaged.
Repair Spalling Immediately
If, during a visual inspection, you see evidence of spalling, which is the detachment of large concrete pieces, an immediate repair is required. Spalling can be a potential life safety issue.