It's a common sight come spring: concrete park benches sporting new cracks and spalls. The short answer is yes, concrete benches are particularly vulnerable to damage during winter, and the primary culprit is the freeze-thaw cycle. Here’s how it works and what can be done.
Water is concrete's enemy in cold weather. Even seemingly solid concrete is micro-porous. During wet autumns or winter thaws, moisture seeps into these tiny pores. When temperatures plummet, this trapped water freezes and expands by about 9%. This expansion creates tremendous internal pressure, stressing the concrete from within. Repeated cycles of freezing and thawing—common in variable winter climates—cause this pressure to build and release, eventually leading to surface cracks, flaking (scaling), or more significant structural breaks.
While high-quality concrete mix and proper installation can improve durability, no pour is completely immune. Benches with existing hairline cracks or poor drainage are at highest risk, as they allow more water ingress. Salt used for de-icing can worsen the damage by increasing the frequency of freeze-thaw cycles and causing chemical deterioration.
Prevention is key. Applying a penetrating silane-siloxane sealer every few years creates a water-repellent barrier, significantly reducing moisture absorption. Ensuring proper drainage around the bench base so water runs away, not under it, is also crucial. For maintenance, promptly filling small cracks with concrete caulk before winter can prevent them from becoming major issues.
So, while the classic concrete park bench is built for endurance, winter weather poses a genuine threat. Understanding the freeze-thaw process highlights the importance of proactive sealing and simple maintenance to keep our public benches intact and functional for years to come.