What is teak wood?
Properties, grades and the question of oiling
Teak has the reputation of being the wood for outdoors. How durable it actually is, however, depends not on the name but on which part of the trunk was used. This page covers the teak tree itself, what the trade grades A to C really mean, why the standard rates heartwood only, and whether you should oil your furniture.
Teak wood furniture starts with the tree
Teak is not a trade name but the wood of one particular tree species. Its origin, growth and natural make-up explain why it works outdoors.
Tectona grandis, a tropical hardwood tree
The teak tree belongs to the mint family and grows 25 to 30 metres tall, with a trunk reaching up to 1.5 metres in diameter. It is native to South and Southeast Asia, above all India and Indonesia, and also grows in Cambodia, Laos and Thailand. It is additionally cultivated in West Africa as well as in Costa Rica, Panama and Brazil.
The oils and resins are already in there
What makes teak special are its natural oils and gum resins. They make the wood resistant to water, insects and rot without any chemical treatment. That is why teak has always been used for ship decking, and why it needs no preservative outdoors. Asked directly whether is teak waterproof, the honest answer is that it resists water exceptionally well but is not sealed the way a coated surface would be.
A heavy hardwood
Teak comes from a broadleaf tree and is a hardwood with the density to match. Kiln dried, at around 12 percent moisture content, it weighs 650 to 750 kilograms per cubic metre. You notice it when carrying a bench, and it is a first clue when checking whether what you have is genuine teak.
From trunk to furniture part
Felling usually happens in the dry season, so the wood carries as little moisture as possible. After cutting, the timber air dries for several weeks to months, then it is planed and sanded. Grading comes last, and that is what decides durability.
How durable is teak really?
The durability of wood against wood-destroying fungi is classified by the European standard EN 350 in five classes, measured as the mass loss of a sample under test. Class 1 means very durable and corresponds to a mass loss of no more than 5 percent. Asian teak is placed in this top class. For comparison: oak sits in class 2, larch and Douglas fir in class 3 to 4.
The most important sentence in the standard is rarely quoted in the trade: durability classes refer exclusively to heartwood. Sapwood, the outer and younger part of the trunk, is always regarded as not durable unless test data show otherwise. A piece of teak furniture is therefore durable only if heartwood was actually used.
Figures such as class 1 to 2 are not a sign of uncertainty but are provided for in the standard. If test values spread across two classes with at least 40 percent falling in each, the range is stated instead of an average. Wood is a natural material, and the origin, site and age of a tree all show up in the measurement.
Grade A, B and C, and what sits behind them
Teak grades sound like a question of looks, but at their core they describe the ratio of heartwood to sapwood. Read alongside the standard, they tell you directly how long a piece will last outdoors.
| Grade | What is used | Appearance | What the standard says |
|---|---|---|---|
| Premium, teak Grade A | heartwood of mature trees only | evenly golden brown, clear grain | durability class 1 applies to this wood |
| Medium, Grade B | mix of heartwood and sapwood | moderate colour variation, less even grain | only the heartwood portion carries the class |
| Standard, Grade C | mostly sapwood | marked colour variation | sapwood counts as not durable under the standard |
| Reclaimed | salvaged timber from buildings or boats | varies widely, patina and wear marks | the class follows the original timber, not its age |
| Plantation | plantation grown timber | usually good to very good quality | often less resistant than wild grown teak |
Which teak we work with
For the teak garden bench from our own production we use Grade A teak from Indonesia, which is pure heartwood. Durability class 1 therefore applies in full.
The rest of our teak range, meaning benches, chairs and tables, comes from our partners' production. Grade and origin differ there from item to item. We deliberately make no blanket claim about the whole range and will tell you the details for the specific piece on request.
For made-to-measure garden furniture, teak sits alongside cumaru, garapa, Douglas fir, larch and oak. The other five are either European timbers or South American hardwoods, and they differ considerably in durability.
Oiling teak wood or letting it grey, a decision
Left untreated, teak develops a silver-grey patina outdoors. That is neither damage nor a loss of quality, just a change in the surface. Even so, decide early, because there is no workable middle way.
Option one, let it grey
You do nothing beyond occasional cleaning. Over one or two seasons the wood turns evenly silver-grey. Durability does not suffer, because it comes from the natural oils inside the wood rather than from the surface. This is the lowest-maintenance and most predictable route.
Option two, keep the golden brown
To retain the original colour, oil the wood and repeat once a year. The oil preserves the colour and adds a protective layer on the surface. What matters is the regularity, not the quantity.
What you should not do
Oil once and then stop. The wood greys anyway, but unevenly, in black blotches rather than a clean silver. Going back to golden brown then means sanding off the existing patina before re-oiling. None of this is necessary in the first place, since teak brings its own oils.
Cleaning is usually enough
For routine care, water, a soft brush and mild soap worked along the grain will do. No pressure washer, it tears the soft early-wood zones out of the surface. Further instructions are under product care.
How to spot genuine teak
Teak is often imitated or confused with similar looking tropical timbers. Five signs help, best used together.
Colour and grain
Fresh teak is golden to dark brown with a straight, even grain. Strong colour differences within a single component point to sapwood content, and therefore to a lower trade grade.
Surface and smell
Thanks to its natural oils, genuine teak feels smooth and slightly oily and has a distinctive spicy smell, particularly on a fresh cut surface.
Weight
At 650 to 750 kilograms per cubic metre, teak is considerably heavier than most European softwoods. A suspiciously light piece is a warning sign.
Ask about the grade
The most reliable check is simply to ask: which grade, how much heartwood, what origin. If no one can answer that, treat the price with caution.
Frequently Asked Questions
Sources
- EN 350:2016, Durability of wood and wood-based products. Freely accessible standard preview with durability classes 1 to 5, the mass loss thresholds and the note that the classes apply to heartwood only
- Durability classes under DIN EN 350, overview by the Bartel expert practice and the registered architect Hans-Joachim Rüpke, with the classification of individual wood species
- Teak garden bench from our own production in Grade A
- All teak garden furniture at Germes
Last reviewed: 24.08.2026 · Reviewer: Germes-Team
Teak, cumaru or European timber, which suits your garden?
Tell us where the furniture will stand, how much sun and rain it gets and whether you want to maintain it or not. We will tell you which wood fits.