Concrete sealing / resealing The application of a liquid chemical compound over a cured concrete surface to protect it from moisture infiltration, chemical stains, and freeze-thaw damage.
NYC winters are incredibly harsh on concrete due to the frequent freezing of absorbed water and the heavy use of rock salt, which chemically attacks concrete. Concrete sealing creates an invisible, hydrophobic barrier that prevents water, salt, and deicing chemicals from penetrating the porous concrete. Resealing public sidewalk flags every two to three years helps prevent surface scaling and spalling, keeping the walkway compliant with DOT standards.
Frequently Asked Questions About Concrete sealing / resealing
What does concrete sealing do?
It creates a water-repellent barrier that limits how much moisture, salt and de-icing chemical soaks into the porous concrete.
Why does it matter in NYC?
Frequent freeze-thaw cycling plus heavy rock salt use are the two main drivers of surface scaling and spalling on city sidewalks.
How often should a sidewalk be resealed?
Commonly every two to three years, though exposure, traffic and the product used determine the actual interval.
Can new concrete be sealed immediately?
No. Fresh concrete needs to cure before sealing, and applying too early can trap moisture. Follow the product's cure-time requirement.