Teak has a reputation for being difficult to maintain. In fact, unvarnished teak is one of the most practical materials to clad a boat deck, and a well-tended teak deck can last a century. The wood is slightly oily, which means it naturally repels mildew, discourages insects, and does not become waterlogged. It is also non-slip, due to the unusual composition of its grain: the light parts of its grain are softer than the dark streaks, meaning that the surface of the wood gradually wears into narrow ridges.
Teak naturally fades to a silvery-grey colour when exposed to UV light: this has no effect on the strength or condition of the wood, but can make your boat look tatty and tired. Crew looking after teak decks often ‘over-maintain’, as we try to get that desired golden colour.
There are two basic steps to caring for your teak decks: cleaning and oiling. (Some teak decks also need annual re-caulking, but that is a big job and won’t be covered here.) The purpose of cleaning is to slough salt and dirt off the deck, and also to scrape off the greyish top layer. Generally, you shouldn’t clean large expanses of teak with anything you wouldn’t put on your hands. Slop it on, leave for 15-20 minutes to soften the dirt, and then brush the deck with a soft brush. Make sure you brush across the grain of the wood, to avoid gouging out the softer wood. If there are any stains remaining, they can be treated by a spot application of oxalic acid. Never sand teak – you will flatten the grain, leaving dangerous slippery patches.
After a day drying out in the sun, the deck is ready for oiling. The ideal treatment for teak is a blend containing tung oil; you can also use linseed oil, which stains the wood dark but is much cheaper than specialist products. Three thin coats of oil work better than one thick coat, as the top layer of oil always wears away quickly. Some boat owners like to use mineral oil to dilute the first layer of teak oil, to make it penetrate further into the wood. Rub on the oil with a cloth, let it sit for at least 4 hours (overnight is better), then rub off excess with a clean dry cloth. The final step is important. Any leftover oil will cure in the sun and make the deck unpleasantly sticky.
Cleaning and oiling can be tedious, but they are the key to maintaining the condition of your teak – if the oil levels in the wood become depleted, the grain structure of the surface opens, allowing moisture in. To prolong the periods between treatments, you can apply a sealer, which filters UV light. Annoyingly, sealers can’t bond to oily surfaces; this means you can’t apply sealer until 2 weeks after your last oiling, and you’ll need to rinse your deck with acetone to make it bond.
Teak decks typically need to be treated about once every six weeks, but this varies. Sunlight breaks down the teak oils, so a boat moored in Florida will need more attention than one used in Finland. And, of course, it depends on how you want your decking to look. A high-gloss ‘millionaire’s yacht’ finish will need regular attention, but faded grey teak can be just as strong as highly-polished wood. Whether you prefer a low-maintenance natural look or a sleekly glistening deck, a little effort will allow your teak decks to last for years.