Teak outdoor furniture

Why teak survives outdoors

Teak is not weatherproof because of anything done to it. It is weatherproof because of what is inside it. The heartwood contains extractives — including naphthoquinone compounds — that are hostile to the fungi and insects that destroy other timbers outdoors, and a high density of tyloses that physically obstruct the vessels water would otherwise travel along.

That is why a teak bench can sit in a garden for decades with nothing applied to it and remain structurally sound. It is also why every claim about teak has to specify which part of the tree. Work published in BioResources found that heartwood positions in 20-year-old teak were highly resistant to fungal attack with mass losses under 10%, while positions closer to the pith and in the sapwood only reached the weaker resistant classification. The USDA Forest Products Laboratory makes the same general point across species: heartwood is what carries decay resistance, and sapwood does not inherit it.

Grade A, B and C — what they mean

These are trade descriptions rather than a regulated standard, so treat them as a rough guide and verify what you can see in the product photographs.

What to look for in the photographs

• Uniform color across every component, not just the seat slats.
• Tight, roughly parallel grain rather than wild figure.
• No pale streaks running along an edge — that is sapwood.
• Stainless or solid brass hardware. Plated steel bolts in a teak chair are an immediate tell about the rest of the build; teak itself is fine with 316 stainless near the coast.

The graying question

Left outside, teak turns from honey-brown to a soft silver-gray, usually within about a year. This is the single most misunderstood thing about the material. The graying is a surface photo-oxidation of lignin roughly 0.1 mm deep. It has no effect whatsoever on strength, decay resistance or lifespan.

So the choice is aesthetic. Let it gray and do nothing, and you own a low-maintenance object that many people think looks better. Keep it honey-colored and you have signed up for cleaning and re-oiling at least annually, because oil weathers off.

Plantation versus old-growth

Almost all teak furniture sold today is plantation-grown, typically from managed estates in Indonesia. Plantation teak grows faster, which produces wider growth rings, a higher proportion of juvenile wood and generally lower extractive content than slow-grown old-growth Burmese teak.

In practice, good plantation teak still clears twenty years outdoors. It is not the equal of century-old timber, but the honest comparison is not old-growth teak — it is the acacia set at a third of the price, and against that, plantation teak wins clearly.

Sustainability is a real consideration here in a way it is not for plastics. Look for FSC certification or an equivalent chain-of-custody claim, and treat its absence on an unusually cheap teak product as a question worth asking.

What teak actually needs

Very little, and most of what people do to it is optional:

• Keep joints clear. The genuine threat is wet debris sitting in corners and around fasteners, holding moisture against end grain indefinitely. A brush-out twice a year does more than any product.
• Get it off standing water. Feet in a permanent puddle is the one condition that will eventually soften even good teak.
• Clean it when it looks dirty. Gray is fine; black streaking is mildew, and a proper teak cleaner lifts it without the aggressive sanding that thins a board every time you do it.
• Oil only if you want the color. Expect to redo it annually.

If a teak set has gone gray and blotchy and you want the color back, the sequence is on our restoration page — and the chemical route removes far less material than sanding.