At our outdoor bench factory, we attach slats using a dual-fastening system that combines high-grade stainless steel screws with a marine-grade structural adhesive. We never rely on glue alone, because outdoor conditions—rain, UV exposure, freezing temperatures, and humidity—can break down adhesive bonds over time. Every slat is first carefully milled to fit the frame, then coated with waterproof glue on the mating surface. After that, we clamp the slat in place and drive two countersunk stainless steel screws through both the slat and the underlying support rail. This creates a mechanical lock that holds the slat firmly even if the adhesive eventually degrades. The screws are corrosion-resistant and slightly recessed, then covered with a weatherproof wood filler to prevent water from seeping into the fastener holes. Our engineers also account for wood expansion and contraction by leaving a small gap between slats and using oversized pilot holes, allowing the screws to move slightly without loosening. This combination of adhesive and hardware ensures the slats stay secure for decades, while preventing squeaks, warping, and premature failure. We test every bench prototype with cyclic loading and accelerated weathering, and the screw-and-glue method consistently outperforms glued-only or clipped systems. So if you need a bench that truly lasts for years, you can trust that our slats are screwed in and bonded, not just glued.