How to Fight Mother Nature

by Alan Noel

During my many years as a finisher, a lot of clients have asked me to either finish a new exterior door or refinish an existing door that has become very dark and unattractive or completely bleached out from the sun. Blame mother nature for that and of course the lack of exterior finishes that will stand up to the blistering hot sun, the cold of winter and everything else Mother Nature can throw at it. Like everything else, wood expands and contracts with the temperature and to some extent, barometric pressure. Because of this movement the finish on the door has to move with the wood in order to stay put, otherwise the finish has no choice but to flake off as the wood moves about more than the finish can stretch. Although painting wooden elements that are exposed to the weather will, in the long run, do a much better job of preservation, some success can be had if you choose the correct clear finish to begin with, and are willing to follow up with all the steps required to maintain it.

Here's what I recommend:

  1. Always use a Spar varnish that is specifically designed for exterior use.
  2. Look for Spar varnishes that have UV inhibitors already in the can.
  3. If staining, pigmented stains are much more light fast and will fade far slower than dye stains.
  4. Only apply what the manufacture's directions say to. Too many coats of finish will cause the film to crack much faster because it has to move with the wood. Too thick and failure will follow soon thereafter.
  5. Be sure to apply the same amount of finish to each end, and to the top and bottom as well. Most doors I've look at show distinct signs of failure in these areas first.
  6. Every 4 to 6 months, the door should be sanded with 120 grit paper, cleaned and then recoated. Otherwise,moisture will wick into the finish and the wood will start to absorb the moisture, expand and the finish will start to flake off because it can no longer hold on to the substrate.
  7. Expect to strip and completely refinish the door every 2 to 3 years depending on how well your maintenance schedule is carried out and to what extent the door is exposed to the elements.
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