Black Locust is a native Appalachian hardwood with 150+ years of proven outdoor performance — no chemical treatment, no annual maintenance, and no industrial processing. It offers a documented field record Accoya can't yet match, while delivering the same premium aesthetic that high-end architects and homeowners are looking for.
Visit black locust lumberAccoya has built a product with strong sustainability credentials and a confident 50-year warranty. But Accoya itself has only existed commercially since the early 2000s — the longest any real Accoya deck has been in service is roughly 20 years. Its 50-year claim is a projection from accelerated laboratory testing, not from anything actually standing for 50 years. Black locust doesn't need a projection. It has a hundred-plus years of fence posts driven into Appalachian ground by farmers who weren't running an experiment — still there, untreated, undisturbed, still doing their job.
Black locust has been trusted by Appalachian farmers for over a century — fence posts in the ground for 80 to 100 years with no treatment whatsoever. That same natural density and oil content is what makes black locust an exceptional architectural decking material. Accoya is engineered to resist moisture through acetylation, but the longest any real Accoya installation has existed is roughly 20 years — its 50-year warranty is a lab projection, not an observed result.
Accoya's acetylation process is industrial and adds real cost to a softwood base. Black locust skips that step entirely: it's sawn, air dried, and finished, with no chemical treatment required to hit the same 50-year warranty. For homeowners and project managers calculating true cost of ownership, a naturally durable hardwood with no added process is the simpler, often more economical choice.
Accoya starts as radiata pine grown on plantations, then ships to an industrial acetylation facility in the Netherlands or Tennessee before it becomes a finished board. Black locust grows in the Appalachian Mountains, is harvested locally, air dried naturally, and finished by an Amish sawmill in Central Pennsylvania. One material crosses an ocean and a chemical plant to get here. The other doesn't leave the region.
Accoya is pale yellow and engineered for uniformity — most installations are coated or pre-dyed because the acetylated wood doesn't develop much character on its own. Black locust comes in a warm golden-yellow that weathers naturally to a silver-gray patina over time — no staining, no oiling, no intervention required. That natural transformation is part of what architects and homeowners come to love.
Accoya's dimensional stability is exceptional — among the best of any decking material on the market. The acetylation process reduces shrinkage and swelling far more than any natural hardwood can match, including black locust. For projects where extremely tight gaps and minimal seasonal movement are critical (large unbroken deck surfaces, certain marine applications, areas with extreme humidity swings), that stability is a genuine advantage.
The table below compares black locust and Accoya across the factors that matter most to architects, contractors, and homeowners specifying long-life exterior decking. Data is drawn from published species and product specifications, manufacturer documentation, and 25 years of field experience supplying architectural-grade black locust.
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These are the questions architects, contractors, and homeowners most often raise when deciding between black locust and Accoya for a long-life exterior decking project.
Accoya is a fine product, and we mean that. But the question worth asking is straightforward: would you rather build with a hardwood that has already lasted a century in the ground, or with a chemically modified softwood whose 50-year claim is still being projected from lab tests? We think the answer writes itself.
