Caring for your teak can be done by yourself or a professional. If you choose to do it yourself, the easiest way to care for your teak is to clean it. You can do this by just hosing it off and keeping it clean. The sun will lighten and bleach the teak and the water will keep it clean. If you do not want your teak to grey, then you need to seal it. You can buy teak sealer at the local hardware store like OSH or a marine store like West Marine. There are many different teak oils and sealers to choose from. If you choose to have a professional care for your teak, make sure they are experienced with working with teak. Many painters and handyman will tell you they know how to care for teak but many times this is not true. Teak is a special type of wood and it requires the knowledge and knows how to maintain it. Always question their background and find out how many times they have cared for teak. Always hire someone who is licensed and insured so your home and the furniture are insured against loss. Never, ever hire a person to work on your teak that does not have experience. They will only end up ruining the teak furniture and then when you do find a professional to fix it, it will cost twice as much because you will have to remove the finish that was put on the teak furniture incorrectly first before you can care for the teak the way it was intended. Teak care is not to be underestimated.
To clean teak, all you need a is a stiff bristle brush and a hose. Wet the teak, all over and brush with the grain. This will remove the dirt, mold, mildew, pollution and surface dirt. Hose off the teak again and the natural wood will be exposed. Repeat this process until you get the desired result you wish. You cannot over clean the teak but if you brush the grain too hard or too much, it may make the teak rough to touch after it dries, and you may need to sand it smooth if you so desire.
To properly restore teak, there are three very important steps. 1st the teak needs to be cleaned properly. If you the teak does not get cleaned and all of the dirt, grime, pollutants, etc. are not removed from the grain of the teak, then the finished product will never look the way it is supposed to. 2nd, the teak must be sanded to smooth the grain and roughness that occurs naturally and also when the teak is cleaned. The last step involves sealing or oiling the teak to nourish the wood and to protect it from turning grey. Be careful to not skip any steps because if you do, then your teak will end up looking blotchy and not restored back to its original state.
When it comes to sealing teak, there are hundreds of products on the market but they all fall into 2 categories. The categories are Oil based sealers and Water Based sealers. Oil based sealers or commonly called teak oils are very popular and work well but they tend to only last for a few months before they fade, and they need to be reapplied. A very common teak oil on the market is Watco Teak Oil. (https://www.rustoleum.com/product-catalog/consumer-brands/watco/teak-oil-finish) When applied properly, which involves first prepping the teak by cleaning and sanding it or if the teak is new, using alcohol to remove soft grains from the wood. The next step is to apply the teak oil, let it soak into the grain and then remove the excess by wiping it down with a dry, clean rag. Repeat this process but be very careful to not leave excess oils on the teak because it will harden and leave a sticky mess to clean up later. The 2nd type of sealer is a water-based sealer. The most common is Semco Teak Sealer. (http://www.semcoteakproducts.com) Semco Natural Teak sealer, unlike an oil-based sealer, will seal the teak but leave it looking raw and its natural color tone. This is the major difference between water-based and oil-based sealers. If you want a natural look, then use a water-based sealer.
Teak is an exotic hardwood. It contains resin that helps protect the wood, giving it a natural resistance against water, insects, and rot. It is routinely used on ocean-going ships for its functionality and beauty and commonly used for woodworking in homes and businesses. But even though teak is weather-resistant, it still needs to be finished to provide permanent protection. Finishing products that contain linseed, tung, lemon or walnut oil can be used on teak. These products work differently than surface coatings like lacquer or varnish. Oil finishes penetrate into the cells of the teak where they harden to protect from the inside out. These products work well on exterior teak doors or trim. They do not provide a glassy surface coating like lacquer or varnish, but they hold up better against sunlight and weather. Marine varnish, also known as spar varnish, contains penetrating oils. Marine varnish contains a variety of tree resins, drying agents and solvents combined to create a tough, durable, plastic-like formula that works well on teak. It is sometimes used on exterior doors and trim but is more often used on decks and boats. Marine varnish takes much longer to dry than other finishing products, but after dying properly yields a shiny, hard finish that resists water.
The common misconception is that teak cannot be varnished because of the natural oils in teak. This is simply not true. Teak can be varnished and is really quite easy. The simplest way to have teak varnished is to pay someone to do it that knows exactly what to do. If you choose to do it yourself, then take these steps. Make sure the teak is clean and sanded very well. Prep is everything and if the preparation is not done properly, then the end result will not be ideal. After you make sure the teak is properly prepped, then the next step is very important. Wipe the teak down with a solvent like MEK or Naphtha. This will remove any excess oils that exist in the wood and allow the varnish to adhere to teak. Once the first coat is applied and dries, it is imperative to scuff the entire surface of the teak with 320 grit sandpaper before you apply the 2nd coat of varnish or the 1st and 2nd coat of varnish will not adhere to each other. Apply three or 4 coats of varnish to give the teak the right look and build and voila, beautiful, varnished teak.