Q&A / 

Deck Sealer Test Results – Part 2 Video

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.

Hi, I'm Tim Carter from AsktheBuilder.com. Today is October 12, 2010 and I want to show you the results of the deck stain test that I started on April 30th of this year. I am wearing my favorite fall shirt to honor Mother Nature and her great light show she puts on for us in color with all the fall trees. My shirt doesn't match what Mother Nature offers.

Here are some of the color of the trees around the lake.

Let's go ahead and look at the dock and see what happened in our test. So look at this. Here's our first stain. This is Extreme Defy in Cedar Tone that looks just as good as the day it was applied, in my opinion. It still repels water and there is no mildew.

Immediately next to it is the Extreme Defy in Clear. In my opinion it failed the color test. The test boards are gray. They are just as gray as the untreated boards. It still repels water, which is good, but as far as the color it is pretty bad.

The next sample is Sherwin-Williams Deck Stain in clear. Same thing - it failed. It is very gray. About as gray as the untouched boards adjacent to it. But it still repels water.

Finally, this last section (sorry for the sun shadow) was cleaned at the start of the test, but no sealer was applied. This is the control to see what it would look like if you did nothing. As you can see the two sealers to the immediate left of the control board has the same coloration as the control boards.

So here it the bottom line. If you are going to put a deck sealer or stain on your deck, the test is conclusive. If you want it to look good for at least a year or longer, you are going to have to buy one with a color pigment in it. The color pigments act as a sun screen to help the wood from turning gray. And next spring, I am going to do an extensive test of name-brand sealers similar to this test.


4 Responses to Deck Sealer Test Results – Part 2 Video

  1. Tim, you wrote in an article published June 8, 2012 in the Chicago Tribune to "...not use an oil-based product" in answering a question about refinishing outdoor wood furniture. Instead, you wrote, "...seal it with a pigmented synthetic resin water repellent." However, your deck stain test results show good results with oil-based products. Your winner is oil-based. So, which is it? Did your test change your mind? Please advise. Thank you, Todd

    • The oil-based products inherently are food for mold and mildew. They contain chemicals to combat it, but the chemicals can leach out. With synthetic resin products, you don't have to worry about that.

  2. Tim, I bought and read your ebook 'Cleaning and sealing your deck'. Lots of good information, thanks.
    However one of the questions toward the end was about ventilation under the deck to which you responded not to worry if the deck was less than 24 inches above the ground. Shouldn't that have read that one should worry if the deck is only 24 inches or less above the ground? Lots of moisture and very little drying ventilation.
    I am finding poorly ventilated low to the ground decks are susceptible to premature rot and or damage to the deck surface.

    • You may be right. I'll go back and read that. The truth is if the decking boards have the 1/4-inch spacing that's recommended, you get a decent air flow through the deck. If you decide to build a deck close to the ground, then you automatically are putting it at risk of premature failure.

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