Letting teak go grey: what happens and how to get it right

Teak left outdoors goes grey (gray, in US English). That isn’t a defect or a sign of poor maintenance: it’s what teak does. The real question is whether you like it, and how to make sure it turns an even silver-grey rather than a patchy green. This page explains what happens, what’s normal and what isn’t, and how to go back if you change your mind. The full overview of care routes is in how to treat teak.

What happens when teak weathers

Gloster describes it matter-of-factly: left to weather naturally, teak turns from golden brown to a light silvery grey as the pigments in the surface layer of the wood fade away. That takes six months to two years, depending on the location and the weather (Gloster). The Dutch furniture company Traditional Teak names the sun’s UV radiation as the cause (Traditional Teak, Dutch).

Worth knowing:

• It doesn’t harm the wood. Gloster and the Dutch furniture companies Hartman and Hamilton Bay all say so: greying does not affect the quality (Gloster, Hartman, Dutch, Hamilton Bay, Dutch).
• You can’t prevent it, only delay it. Tribù: the process “cannot be prevented”, but a sealer delays it (Tribù instructions).
• Teak used indoors or on a veranda does not turn grey, according to Tribù (Tribù instructions). Indoors, the opposite tends to happen: the Dutch timber information centre Centrum Hout describes the heartwood darkening under the influence of light (Centrum Hout, Dutch).

The in-between stage: yellow, patchy, uneven

Most questions aren’t about the end result but about the first few months.

• Yellow. Traditional Teak writes that new teak takes on a “pale yellow colour” after about a week outdoors (Traditional Teak, Dutch).
• Oil and pigment washing out. Gloster: during the first spells of rain, oil and pigment wash out of the surface layer; this decreases after about two to three months. During that period, it’s better not to stand new teak on pale, porous natural stone, and to keep pale cushions away in wet weather (Gloster).
• Uneven. Vincent Sheppard warns that the interim appearance “may lack the desired consistency”, and that colour variations in new teak diminish with exposure to sunlight, which can take weeks to months (Vincent Sheppard). Centrum Hout confirms that large colour differences usually disappear after exposure to light (Centrum Hout, Dutch).
• Oil stains. Tribù: an irregular pattern of discolouration from natural oil coming to the surface can be removed with a deep clean (Tribù instructions).

In short: patience. A patchy first season is normal.

Silver-grey is good, green and black are not

The difference between weathering and dirt is the colour.

What you see	What it usually is	What to do
Even silver-grey	natural weathering	nothing, or a protector against stains
Greenish haze	algae and moss after a wet spell	a solution of soft soap and soda
Dark grey to green, patchy	the start of mould	clean; possibly a patina protector
Black dots or a black surface	mould/algae, often on oil	clean; if black from oil: sand

Sources: the Dutch furniture company Souren Meubels names green algae after a wet spell and a solution of 4 to 6 tablespoons of soda (soda crystals) with soft soap, left for 5 to 10 minutes, wiped off and rinsed (Souren Meubels, Dutch). Traditional Teak links dark grey/green and black dots to fungi and algae (Traditional Teak, Dutch). Gloster describes how regularly oiled teak turns black from mould on the oil, which can only be removed by aggressive sanding (Gloster). Vincent Sheppard names rainwater and tree sap as causes of mildew and advises against placing furniture under trees (Vincent Sheppard).

So: if you want beautiful grey teak, don’t oil it. More on cleaning in how to clean teak furniture.

How to let teak go grey properly

1. Do little. Gloster recommends letting teak weather naturally and cleaning it thoroughly once or twice a year with water and a mild detergent (Gloster).
2. Remove leaves, berries and bird droppings quickly, and move pots and plastic coasters regularly, or you get dark marks (Tribù instructions).
3. Optional: protect the grey. For people who like the silver-grey patina, Tribù recommends a protector, applied to new wood after two to three weeks (Tribù instructions). Gloster applies its protector to the weathered surface against food and drink stains (Gloster). Traditional Teak advises leaving new teak outdoors for a week and then applying a patina protector, which counters green discolouration (Traditional Teak, Dutch).
4. No pressure washer: it erodes the soft surface layer and leaves the wood rough (Gloster).

For the full outdoor routine, see how to treat outdoor teak furniture.

Weathered teak: rough, but not broken

After years outdoors, teak can feel rough and “fluffy”. Traditional Teak calls that “a cosmetic problem, not a maintenance problem”: the wood contains enough oil to protect itself against rot (Traditional Teak, Dutch). Gloster advises occasional light sanding to remove raised grain, always along the grain (Gloster). Traditional Teak recommends sanding by hand, because in its view machine sanding can cause black spots from the heat (Traditional Teak, Dutch).

Seeing wasps chewing your furniture in spring or early summer? Gloster explains that they use the soft fibres of weathered teak for their nests (Gloster). Read more in how to clean teak furniture.

Back to brown: removing the grey

Grey isn’t permanent. The discolouration sits in the surface layer, and you can clean or sand it away. There are roughly three ways:

• Teak cleaner. Gloster has dirty or weathered teak treated with its cleaner first, before protecting it (Gloster); Tribù describes a deep clean with soaking time, scrubbing along the grain and a thorough rinse (Tribù instructions). How far that gets you depends on how deep the grey and dirt go.
• Teak brightener (cleaner/brightener). Traditional Teak sells a product that removes deposits and “brings back the original colour of teak”; it can damage grass, plants and some paving, so cover the ground (Traditional Teak, Dutch). The Dutch paint specialist Peltenburg removes the grey with oxalic acid (Peltenburg, Dutch). Some two-part systems from boat care are highly caustic: Starke combines a sodium hydroxide cleaner with a hydrochloric acid brightener and warns of severe skin burns and eye damage (Starke). So read the label and wear gloves and eye protection.
• Sanding. For deep damage, Tribù sands down to sound wood, along the grain, from P80 to P150–P220 (Tribù instructions).

Use no bleach: Gloster writes that it discolours the wood (Gloster). (Vincent Sheppard does mention a weak bleach solution for stubborn wine stains; this guide takes the cautious line.)

Then you have to choose: do nothing, and the teak goes grey again, or apply a sealer to hold the colour for longer. Tribù applies that sealer two to three weeks after first exposure or after sanding (Tribù instructions). Which product suits you is covered in teak oil vs sealer. Is the piece really neglected, with rough wood, black patches or stains that won’t shift? Then read how to restore teak.

Greywash and whitewash: a grey or white look without the wait

If you want a grey or white look straight away, that’s a finish, not natural weathering. A greywash is a semi-transparent grey haze that leaves the grain visible; a whitewash works the same way in white, according to the Dutch paint retailer Verftechnieken (Verftechnieken, greywash, Dutch).

On teak, that has its own pitfalls. Verftechnieken writes that because of its warm undertone, teak can take on a pinkish effect with a whitewash, so a light greywash often works better. Teak is also oily: its natural substances can hinder adhesion and cause discolouration, and any oil on the wood must come off first (Verftechnieken, Dutch). According to the same source, a wax finish is not suitable for outdoors or damp rooms (Verftechnieken, greywash, Dutch).

For garden furniture, the manufacturers are cautious: Gloster writes that paint and varnish don’t adhere properly to teak and start to peel, and advises against any paint or stain other than its own products (Gloster). If you want grey outdoors, simply letting it weather is the easiest and cheapest route. A greywash is therefore mainly an option for indoor furniture.