Teak is an extremely durable hardwood, and it naturally requires a little care or treatment to protect it from the elements. If left untreated, teak wood will eventually weather to a grayish-silver tone color, which is considered to be very attractive by some. This process is purely cosmetic and does not compromise the strength or quality of the wood. Some will purchase teak wood products with the intention of letting it weather because they like the grayish-silver color, while others may prefer to maintain the golden honey-brown color the teak has when it is brand new. If you wish to preserve the look of "new" teak, there are a few different ways to do so.
Teak wood has a natural resistance to mold and rot; though not completely impervious, it is naturally highly resistant due to the high oil content. Despite this, unsightly mildew can form on the surface of the wood if not cared for properly. Mildew, which will appear as black dots or patches, can discolor both the treated and naturally weathered finishes of the wood.
If mildew is present, a simple washing of the teak with a mixture of mild soap and water with a little bit of bleach or vinegar, along with the use of a gentle plastic scrub brush will usually take care of the problem. Many teak manufacturers strongly recommend against using any type of metal brush as they can scratch and damage the wood. For the harder to clean stains or residue, special teak cleaners can be purchased from most local hardware or home improvement stores. Be sure to read the instructions included with the cleaner completely before application and follow them exactly.
The frequency at which you clean your teak will depend on the elements and environment the teak is exposed to. For example, teak used in marine applications will likely require a more frequent cleaning schedule than an outdoor patio set, and even less frequent for indoor uses. Whatever your cleaning needs may be, the use of high-pressure hoses, wire brushes or steel wool is not recommended as these tools can damage the wood.
There are several different methods you could use to clean your teak, including both store bought and homemade cleaners. Strong chemical cleaners can literally dissolve teak, so when cleaning your teak, always start with the mildest cleaners. If you decide you need something a bit stronger to get the job done, make sure the chemicals are safe for use on teak. If the teak has previously been coated with a sealer, teak coating or varnish, it must be removed with the use of a wood-stripper before cleaning and reapplying the oil or coating of choice.
Here are three common, easy to make, homemade solutions used by many teak lovers to clean their teak.
- Mixing 1 cup each of ammonia and laundry detergent (without bleach) in 1 gallon of warm water.
- Mixing 1 cup each of chlorine bleach and laundry detergent in 1 gallon of warm water.
- Mixing 1 cup of vinegar to one gallon of warm water.
Whichever mixture you choose, never, ever combine these solutions together - NEVER combine chlorine and ammonia together as the combination creates an extremely toxic gas.
Apply the mixture to the teak item using a plastic scrub brush, scrubbing while applying the mixture. Allow the cleaning mixture to soak on the teak for about 15 minutes. Then rinse off the teak very thoroughly. Some find it easiest to take the teak item outside for cleaning due to the involved, and often-messy nature of cleaning the item. Taking the items outdoors prevents any drips or spills from damaging the flooring in the home. If you choose not to clean your teak item outdoors, be sure to protect your self from potentially hazardous fumes by making sure the cleaning area is very well ventilated; open doors, windows, and use a fan if available. And as always when working with chemicals, even vinegar due to its acidity, wear rubber gloves and protective eyewear. It is also recommended you wear old clothes that you don't care too much about so that you don't ruin anything nice!
The above cleaning mixtures work well on most household teak items; particularly those that have been somewhat protected from the elements, and only need a mild cleaning. If your teak has been left to the elements for quite a while, or if you live in an area where the air is more corrosive (heavily polluted or near the sea) then you may need a more aggressive cleaning system. However, most wood cleaners are highly caustic and should only be used when everything else has been tried. Many of those cleaners can damage surrounding paint, fiberglass, acrylic, gel coat and metal based surfaces and other wood. Your local hardware or home improvement store will likely have a few teak cleaning options; most commonly you will find a one-part cleaner and a two-part cleaner.
Aside from cleaning, there are three different methods to treat your teak product: oil, sealant or varnish.
Once cleaned, the teak has had all of it's surface oils removed, and if left untreated, will oxidize creating a grayish color on the surface, but more importantly it will soil more easily. Traditionally teak has been treated with organic oils, which help to replenish the oil removed by the environment and regular cleaning process. The oil restores the luster and brings out the character of the wood.
Some teak manufacturers recommend against using teak oils if the item is to be used outdoors due to the increased chance of mildew forming on the surface as the mildew will actually feed off the organic oils. Also, because the oil would need to be reapplied about every 2-3 months, and with each application the teak needs to be cleaned which eventually wears away the surface layers of the teak. Many find the oil method to be too high maintenance for most outdoor applications. Since teak items that are kept indoors would be in a somewhat consistent environment, away from direct sunlight and rain, the oiled finish will last much longer and is less likely to form mildew.
Most teak oils consist of either Tung oil or Linseed oil with added resins to make them more durable. Many professional refinishers prefer Tung oil to Linseed oil because Linseed oil tends to darken the wood, and Tung oil tends to be more water resistant. However, after a few months of exposure, the wood will turn slightly dark with both types of oil. There are many specialized teak oils that address this issue using additives, pigments, UV blockers and mildew retardants.
To apply teak oil, use a paintbrush to "paint" on the oil using even strokes. Use a cloth dampened with mineral spirits to wipe up any excess oil. Immediately wipe away any drips or runs that may get on the surrounding material such as paint or fiberglass as the oil will leave a dark stain. Oiling teak requires multiple coats, and the number of coats applied just depends on your particular wood piece. Essentially, you will repeat applying the oil with a paintbrush and wiping away the excess until the wood will no longer soak up the oil; you will be able to tell this when the oil begins to pool on the surface. Once the wood has soaked up as much oil as possible, the wood should have a matte finish with out shiny spots.
Typically, oil treated teak is not slippery because the oil does not seal the surface, so this treatment method is suitable for walkways, steps, bathing and swimming pool areas. Oiling is not really a way to protect the wood, but rather a way to enhance the rich golden glow of the teak.
Another way got get a "natural" look with your teak is to use a wood sealer. Unlike oils, a sealer will not feed the wood but rather it will seal the surface of the wood protecting it from outside moisture and dirt and will seal in the natural oils and resins. If you are restoring your teak from an exposed, weathered state, then some of the oils and resins have already been lost; in this case the teak should be cleaned and oiled two weeks prior to applying the sealer. This will restore the oils in the wood. Then after about two weeks, give the wood a gentle washing (no harsh chemicals needed, just mild soap and water) and let it dry completely. To be effective, wood sealers need to be applied to an oil-free surface, so once the wood has dried use a rag soaked with acetone to remove the surface oil. The oil that the teak has absorbed when you oiled it will not be affected since acetone evaporates very quickly and will not reach beyond the surface. Most sealers will be applied just like the oil, "painting" it on with a paint brush, but be sure to carefully read and follow the instructions on the sealer. Wipe away any excess and apply more coats until the surface of the teak has a uniform matte finish.
To maintain this finish, wash the teak and re-apply a fresh coat as needed. You will need to determine the frequency that this is needed because this will depend on many things including use, exposure and the general nature of the product; for example, boat owners with exposed teak may have to repeat this process every two to three months, whereas a teak item used in a more residential setting may allow for longer periods of 6-9 months in-between coatings.
The application of varnish to teak is primarily used in marine applications as they are subject to the most extreme conditions such as salt water, constant exposure to the sun and other elements. Depending on your use of the teak item, you may consider using varnish as a long lasting, highly durable finish that will preserve the natural look of the teak. Varnishing teak is quite an extensive and time-consuming task that by no means can be rushed if you want the finish to last. However in the opinion of many professional woodworkers, the end result of your labor will be well worth it.
In order to prepare your wood for varnishing, clean the teak using your preferred method. If your teak is new, use fine grit sandpaper and sand the unit uniformly. Your intention is not really to "sand" the wood, but rather just to rough-up the surface slightly, to give the varnish something to grip onto; this is called giving the wood some "tooth". Follow this up by using a clean rag, or even a vacuum to remove any wood dust. When the loose dust has been removed, wipe the unit over with a different clean rag using either acetone or denatured alcohol to render the very surface free of oils.
If you are refinishing teak that has been left to weather and are bringing it back to "new" you can follow the same steps as above, but with slightly more aggressive sanding until you begin to see the golden-brown teak showing through. As mentioned previously, you can also use specialized teak cleaners that will essentially strip away the grayed surface layer, and usually include some form of wood brightener that will lighten the color
If you are refinishing teak that has previously been varnished or sealed with a sealant, then your teak will require a bit more sanding before you can apply the new layers of varnish. In this case there are many different variables that will determine how aggressive your sanding process needs to be, such as the age of the varnish or the number of layers. Sandpaper is graded using a number system; the finer the paper, the higher the number. Once the old finish has been removed, you will start sanding with 80 to 150 grit sandpaper and work up to 220 grit.
When you are ready to begin varnishing, it is important to be aware of the temperature and humidity level in the area where you will be working. Wood will expand when hot and contract when cold; likewise, the wood can expand if there is a high humidity level as the wood can absorb the moisture. The wood and the varnish should be "room temperature", which is between 70-80 degrees. Hot, humid days and cold, foggy, muggy days are not good for applying varnish. The working area (garage, shop, etc) should be well ventilated not only for your health and safety, but also because the varnish will require a good supply of oxygen. The varnish dries (cures) through the evaporation of the volatile chemical ingredients, and by taking in oxygen from the air. If you are working outdoors try to pick a day with the least amount of wind, with very moderate temperatures and humidity.
When applying varnish your initial goal is to put on several build-up coats to give the final "finishing coats" a good grip on the wood, then with the later layers you want to then level out the surface. A generic coating schedule will resemble something close to this:
Coat #1: Thin the varnish about 50% with a thinner. This thinned coat will basically act as the primer coat. Allow to dry completely (24 hours) before applying the next coat.
Coat #2: Thin the varnish about 20% with a thinner. Do not sand, directly apply 2nd coat. Allow to dry completely (24 hours) before applying the next coat.
Coat #3: Thin the varnish about 10% with a thinner. Do not sand, directly apply 3rd coat. Allow to dry completely (24 hours) before applying the next coat.
Coat #4: Check to make sure the 3rd coat is dry. Then sand with about a 220-grit sandpaper. Apply the 4th coat of varnish at full strength. Allow to dry for at least 2 days.
Coats #5 and 6: Same as coat 4, but sand more heavily in between coats 5 and 6 (allow to dry in between coats) to ensure a flat smooth surface.
Coats #7, 8, and 9: After applying each coat and allowing to dry completely, sand by hand with 320-grit paper in-between coats. Apply full strength with extra care to avoid runs, sags, and drips.
This coating schedule is a basic outline that should suit most applications, however, you may need to adjust the number of coats and how extensively you sand, etc. Basically, this schedule is not written in stone, and there is room for improvisations as you see fit. As always (and we can't stress this enough) read the instructions of your varnish and thinner carefully.
Whether you prefer the warm golden honey-brown look of new teak, or find the weathered silver-gray finish more attractive, taking care to protect and lengthen the life of your teak will allow you to enjoy the beauty and durability of your teak for many years to come.
Make sure to wipe the top of the teak oil can before you put the lid back on otherwise you will have a heck of a time trying to open it the next time you need to oil.
Some have found it useful to sprinkle the floor with water or wet sawdust in order to keep down the dust.
When washing teak doors or other upright teak surfaces lay the soapy water on with a soft brush, starting from the bottom of the surface and working up to the top in order to avoid little streams of water, which will trickle down and mark the unwashed surface below.
Also, remember to allow each coat to dry completely before replacing hardware or using the item - patience will be rewarded with a beautifully warm teak keepsake.