A couple of years ago, we purchased a beautiful teak outdoor table. I sealed it with Semco sealer (recommended by the store for teak) a month after we bought it. To protect our investment, we also had a custom cover made for the table to protect it from rain and sun. Unfortunately, we got a lot of rain recently and when we took off the cover, the teak was covered with mildew spots. The water got through the cover and was trapped inside. I first tried mild bleach to remove the spots. That didn't take all of them out, so I tried a stronger commercial product. This didn't work either and just left the table looking faded and splotchy.

So I'm thinking I should just refinish the surface. I've done some reading on this, and I'm thinking I'll start with 120, then 220, then seal with Semco. Is there anything I should watch out for? How deep to these mildew spots go? Should I use an orbital or straight sander? I'm hoping I won't have to strip off too much of the wood.

Any advice appreciated! Thanks.

photo showing mildew damage

close up of mildew

after sanding

end result. much better!

  • Check this out first, woodworking.stackexchange.com/questions/3778/… If you do end up sanding you'll probably want to start coarser than 120, significantly coarser is not a bad idea as long as you're careful and you sand up through the grits afterwards. By the way is this hand sanding or power sanding and if the latter what kind of sander (belt, ROS etc.)? Now re. the Semco, was the specific product you uses Semco Teak Sealer Natural Tone?
    – Graphus
    Apr 24, 2019 at 18:13
  • Thanks, @Graphus. I do have a cheap pressure washer that I used on my fence. I had read that pressure washing can damage the wood, which is why I shied away from using it on this expensive table. What are pros/cons of pressure washing vs. sanding? As for sanding, I was planning to rent a power sander (either orbital or the straight type) from Home Depot. Yes, I used Semco Teak Sealer but in honeytone (semcoteakproducts.com/semco_products.htm).
    – Techmec
    Apr 24, 2019 at 19:12
  • Pressure washers can damage wood, but then sanding can be thought of as a form of damage too. If you end up sanding, the 'straight type' is a belt sander and it's the right kind of sander for removing a lot of material — they are aggressive, care is needed in handling. Google for more. The orbital or random-orbit type is more a finish sander, although plenty of people these days use them for more than that! You have to be careful with these sanders too, even using finer grits, as it's still very easy to round corners or edges unintentionally. [contd]
    – Graphus
    Apr 25, 2019 at 7:27
  • BTW if you haven't heard this yet it's considered good practice to hand sand (backed by a block) after power sanding, using the same final grit but sanding in the direction of the grain. This is to remove any traces of cross-grain sanding marks. Not everyone does this so it's entirely up to you, everyone decides for themselves what standard of surface they can live with.
    – Graphus
    Apr 25, 2019 at 7:29
  • Thanks, @Graphus, for the great info. I'll work on this this weekend and will let you know how it goes!
    – Techmec
    Apr 25, 2019 at 16:19

1 Answer 1


A few years ago I had the chance to refinish a beautiful teak deck chair. Teak gets that grey color with age, and when you refinish it, a little of that grey actually looks beautiful.

I think you would be making a mistake to sand it heavily, if there are no major marks or gouges, try only sanding with 220, lightly and uniformly. Those little dark speck will come out mostly, and I wouldn't get too crazy about getting them all out. If you over sand one spot to get it out, you will create a bright spot in the finish that looks worse than the little black spot would have.

After that, all you want to do is rub the whole thing with teak oil - you will be astounded by the amazing depth and color of well oiled teak. If I owned this table, I would re-oil it annually, or semi annually, and I would not keep it covered.

  • Thanks, Paul. After a few passes with a belt sander using 220, I did manage to restore the table. I am happy with how it turned out. I should have posted an "after" photo. I'll attach one up top. I'm curious, do you feel teak oil is better than sealer, like Semco? I've read that sealers provide UV protection that prevent graying.
    – Techmec
    Jul 5, 2019 at 3:40
  • @Techmec - I do not have any experience with Semco, so as with any new product - its good to test it on a spot that is not highly visible, like the underside of the table, to be sure you like the look.
    – Paul Davis
    Aug 19, 2019 at 14:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.