Q&A / 

Deck Stain Test Results After Two Years

In May of 2012, I started an extensive outdoor test in real conditions of quite a few name brand deck sealers.  The test was conducted here in central New Hampshire.

The sealers were tested on treated lumber and cedar decking. Both are very popular wood species used for outdoor wood decks and structures.

Here's the list of manufacturers who's products were in the test:

  • TWP
  • Armstrong's
  • Defy
  • Behr
  • Benjamin Moore
  • Wolman's
  • Sherwin Williams
  • Olympic
  • Thompson's

Some products failed within 60 days or so. You can SEE THE RESULTS FOR FREE of dramatic Before and After photos of each sample by going to the opens in a new windowthis page.

The following photos were shot on June 3, 2014, in the shade. Twenty-five months before, in May of 2012, these panels had just been stained and put out to weather here in New Hampshire.

The first photo shows just five pieces of the cedar decking. The reason for that is after just ONE YEAR, a majority of the stain products had COMPLETELY FAILED and it was useless to continue to expose them to the weather. You can see after an additional year of weather, the others are dead on arrival.

But look at the stain samples on the smaller treated lumber. Isn't it amazing the stain is in much better shape on just about every one! What's more, there's very little mildew or mold on any of them. For the most part, they look quite good.

The reason, I believe, is the treated yellow pine absorbs the stain more as opposed to the harder summer wood found in the cedar. Cedar also has natural oils in it that act as a natural preservative. I suspect these oils interfere with the adhesion of the stains on the wood.

The copper in the treated lumber, I believe, leaches out through the sealers. Copper is a natural biocide and its presence stops the growth of mildew and mold.

NOTE FROM TIM CARTER - Founder of AsktheBuilder.com - posted October, 2016: I no longer would apply Defy deck sealer to any exterior wood that I own at my own home.

These are cedar wood samples. All of the stain products have now failed. Photo credit: Tim Carter


Stain Test Panel 2

This is the beginning of the treated lumber samples. Note that each of the photos overlaps the one before/after it. You can easily see this. Photo credit; Tim Carter


Stain Test Panel 3


Stain Test Panel 4


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