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Independent Deck Finish Results

Independent Deck Finish Test 2000 Results

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.

Start the presses! The raw data from the latest Earlham University study about deck sealer performance has just been received! The final report will take a few weeks to be generated but the visual findings tell the tale. The actual findings were just released to me moments ago on May 2, 2001.

Why are these test results so important? It just so happens that outdoor deck cleaning and sealing happens to be one of the most important topics I have ever covered. I have discovered that homeowners like you are disgusted with the poor performance of the heavily advertised brands you see on TV and those that clutter the shelves of many of the big box home centers that dot the fruited plain.

On November 1, 2000, the Earlham Analytical Testing Labs located in Richmond, Indiana started a weathering test of 30 deck finishes. To make sure apples were being compared with apples only penetrating semi-transparent finishes were tested. This is important! In other words, clear finishes that contain little UV protecting pigments were not included in the study.

It is not uncommon for the testing procedure to look at the samples after 6 months and then continue on with the testing until certain products begin to fail. Preliminary results of this ongoing, independent testing on penetrating semi-transparent wood finishes indicates that the products listed below are ranked in the top five, based on performance in ASTM water repellency testing and six months of outdoor exposure. The five products listed in alphabetical order are:

  • DEFY Penetrating Water Repellent Wood Finish manufactured by SaverSystems div. of Meredith, Inc. is a water-based, synthetic resin formula. Comes in a range of colors.
  • F & P Premium Wood Finish manufactured by Wolman Wood Care Products, is an oil-based formula.
  • Sikkens Cetol manufactured by AKZO Nobel Coating, Inc. is an oil-based formula.
  • Storm Stain Linseed Oil Alkyd Decking Stain manufactured by California Products Corp. is an oil-based formula.
  • TWP Total Wood Preservative manufactured by Gemini Coatings, Inc. is an oil- based formula.


These are the six months preliminary results. Check my website periodically for further data concerning this ongoing testing. As soon as the final test results are in, I will post them at my website.

Synthetic Resins vs. Natural Oils

Only one of the top five performers is a synthetic resin based product. Natural oil products often become food for mildew and algae once the mildewcides and fungicides in the finishes are damaged by sunlight and/or dissolved away by repeated rainfall or snow melt. This may be the biggest reason your past deck finishes have turned black or green. The mildew and algae were actually eating your deck finish. This is often not a problem with synthetic resin finishes.

No matter which product you choose to use, read the directions and follow them closely. I have personally used Defy on my wood porches over the years and have had great success. Many, many past readers of my columns and bulletins have also had huge success with Defy. I get phone calls, e-mails and letters with photos on a regular basis from homeowners just like you that love the performance of Defy. Remember, follow the directions of any product to get long lasting results.

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.

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One Response to Independent Deck Finish Results

  1. I have a porch that I want to seal with a material that will glue down the splinters so that I can grind it then put down a finish.

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