When you sit on a sturdy urban bench, you're experiencing the result of deliberate engineering. The fasteners holding those slats in place are far from an afterthought—they're critical components chosen for security, durability, and public safety. So, what exactly is used?
Professionals typically rely on high-grade, corrosion-resistant fasteners. The most common and trusted choice is stainless steel bolts, nuts, and washers, often from the 304 or 316 series for their excellent resistance to weather and rust. For added security in high-traffic or vandal-prone areas, tamper-resistant or vandal-proof fasteners are essential. These include bolts with unique, proprietary drive systems (like pin-in-torx or spanner heads) that require special tools to install and remove, deterring unauthorized disassembly.
The installation method is just as important. Through-bolting—where a bolt passes completely through the slat and the bench frame—is the gold standard for strength. Each connection is secured with a nut and lock washer on the underside to prevent loosening from vibration and use. For a cleaner look, some designs use counterbored holes, where the bolt head sits flush with or slightly below the wood surface.
Beyond bolts, structural adhesives are sometimes used as a complementary measure. A bead of high-strength, outdoor-rated construction adhesive applied before bolting creates an additional bond that resists racking and movement, though it should never replace mechanical fasteners.
The goal is always a permanent, rigid connection. These fastener systems ensure that each slat stays firmly anchored, season after season, supporting daily use while minimizing maintenance needs for the public spaces we all share. It's a simple answer with sophisticated engineering behind it: the right metal, the right design, and the right installation keep our urban benches securely under us.