Great question, and honestly one of the most important things to consider before buying or building any outdoor bench. The short answer is: it depends entirely on the type of wood, how it was treated, and where you live. But let me walk you through what actually happens in the real world, not just marketing claims.
First, naturally rot- and insect-resistant woods are your best friends for outdoor benches. Teak, cedar, redwood, white oak, and black locust all contain natural oils, tannins, or resins that many wood-boring insects find unappetizing or even toxic. Teak and cedar, in particular, are famous for this. A properly maintained teak bench can sit outside for decades with almost zero insect damage. Cedar smells amazing to us but repels termites, carpenter ants, and powderpost beetles. Even then, these woods are not 100% insect-proof — they’re just highly resistant. In heavy termite regions, even cedar can eventually get nibbled if the wood stays constantly damp and the natural oils have weathered away.
Pressure-treated pine is the budget-friendly workhorse. Southern yellow pine injected with copper-based preservatives (like ACQ or copper azole) becomes quite unappealing to insects. It’s not the copper itself that kills them — it’s that the treatment makes the wood toxic or distasteful to termites and beetles. But here’s the catch: pressure treatment only penetrates the outer sapwood. If you cut a board after purchase, the exposed ends expose untreated wood. And after a few years of sun and rain, the surface protection fades. You’ll need to reapply a wood preservative or stain every year or two.
Untreated softwoods like spruce, fir, pine, or poplar are essentially insect candy in many climates. A bench made from plain construction-grade pine left outside will almost certainly attract carpenter ants, termites, or wood-boring beetles within one to three seasons, especially if it sits directly on soil or in a damp, shaded corner. I’ve seen untreated pine benches literally crumble from powderpost beetle galleries after a couple of humid summers.
Now, what actually makes insects attack in the first place? Moisture. Almost all wood-destroying insects need damp, softened wood to chew through easily. If you keep your bench off the ground (use feet or pavers), allow air circulation underneath, and keep the surface sealed with a good exterior oil, stain, or spar urethane, you dramatically reduce insect pressure. A bone-dry, well-maintained bench is rarely attractive to termites or carpenter ants, even if the wood species is only moderately resistant.
A few practical tips from my own experience fixing up old outdoor benches:
1. Check the end grain. That’s where water wicks in and insects enter. Seal end cuts with a wax or end-grain sealer immediately after cutting.
2. Choose naturally resistant wood if your budget allows. Even a cedar or white oak bench from a big-box store will outperform a cheap pine bench ten to one against bugs.
3. Reapply protection seasonally. I use a penetrating exterior oil with added insect repellent (many contain natural cedar oil or synthetic pyrethroids) every spring. It takes fifteen minutes and buys years of extra life.
4. Keep it dry. If the bench sits under a tree or against a wall where it never fully dries after rain, move it. Sun and airflow are the cheapest pesticides you can get.
So for the bench you’re asking about — if it’s teak, cedar, or properly pressure-treated pine, you’re in good shape. If it’s bare untreated softwood sitting on grass in a humid climate, start planning for replacements or at least treat it now. And remember, no wood is truly immune forever. The best defense is a combination of good species choice, regular sealing, and keeping the wood dry. That combination will hold up against insects far better than any single “miracle” product.