Synthetic Deck Sealers
Summary: Algae and mildew are eating on your deck. Get that film forming
synthetic deck sealer off your wooden deck. Apply a synthetic resin
water repellent sealer and you and your family will be the only ones
eating on your deck.
Related
Articles: Protect Decks, Deck Sealers Report
DEAR TIM: I have a wood deck, boat dock and picnic table that needs to be cleaned and sealed. I also just purchased new outdoor wood furniture. I have been less than satisfied with previous wood sealant products. Does my new wood furniture require immediate sealing or should I wait a month? What is the best way to clean and prepare wood to be sealed? Are certain wood sealants better than others? What is the average life span of a high quality wood sealant? Pat - Meredith, NH
DEAR PAT: I can absolutely understand your frustration with wood sealant products. There are many products all claiming that they are top performers. The sad truth of the matter is that many of them are inferior products. Fortunately, advancements in coatings technology has produced some synthetic penetrating water repellents that will make you quite happy.
Wood that is used to construct boat docks, decks, handrails, picnic tables or any other horizontal outdoor surface is subjected to the absolute harshest weathering conditions. Unprotected wood absorbs enormous amounts of ultraviolet (UV) radiation from the sun. UV rays can actually blast apart lignin within wood. This is the glue that bonds wood fibers together. Rain water and snow melt can pond or pool on flat boards. This water can easily be absorbed by the wood causing it to swell. When the sun or wind dries the wood, it shrinks. The shrinkage forces cause cracking, twisting and warping. Conventional pressure treatment chemicals used in treated lumber will inhibit rotting but will not stop these other destructive and unattractive phenomena. New wood needs to be sealed immediately. Water and sunlight begin to destroy it as soon as it is exposed to these elements.
Do not use chlorine bleach (sodium hypochlorite) to clean your wood! It is a very strong oxidizer that will remove the natural color from your wood and destroy the lignin in the wood. In addition, chlorine bleach is highly toxic to any vegetation surrounding your deck. A neighbor of mine systematically tortured and killed a large tree next to her algae covered patio. She achieved this by using chlorine bleach to remove the green haze. Beware! Many off the shelf deck cleaners contain chlorine bleach. Study the product label before you buy. If you see the words sodium hypochlorite, this means the product contains chlorine bleach.
Oxygen bleach should be used with moderate caution if it is used to clean redwood. It can sometimes darken the wood. This happens most often with freshly cut redwood that has a low pH value. As redwood ages its pH value becomes more neutral and the oxygen bleach will not darken it. The California Redwood Association recommends using oxalic acid to clean redwood.
Dirty and weathered cedar can be cleaned with oxygen bleach. The results are spectacular. Once clean, the cedar looks like new. Oxygen bleach also helps to remove mill glaze from new cedar. It opens wood pores so that your deck sealer will penetrate more deeply.
When selecting a sealer, try to choose one that is a penetrating water repellent. Look for ones that are formulated using synthetic oils and resins. Some are available that are water based. You can often clean and seal your deck the same day if you use a water based product. Choose a sealant that is moderately pigmented. The pigments in sealants do a great job of reflecting and absorbing harmful UV rays.
Many popular sealants found at paint stores and home centers contain natural oils like linseed oil, vegetable oil, animal fats, and tung oil. These natural oils are actually food for mildew and algae. To stop the organisms from feasting on sealants that contain natural oils, manufacturers have to add mildewcides and fungicides. Unfortunately, these chemicals are often water soluble. Rain and snow can dissolve them and wash them away leaving a deck unprotected. That is one reason why many decks turn black or green in just six to nine months. Synthetic penetrating water repellents do not contain food for mildew and algae.
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from Tim: Years ago while researching a column about cleaning decks, I discovered the wonders of Oxygen Bleach. It is perhaps the 'greenest' cleaner I know of as it uses oxygen ions to break apart stains, dirt and odor molecules. There are no harsh chemicals, and it works on just about anything that is water washable. I decided to create my own special blend using ingredients made in the USA. In fact, the raw materials in the active ingredient are food-grade quality registered with the FDA. I call my product Stain Solver. I urge you to use it to help clean your deck surfaces. You will be amazed at the results! |
Avoid using sealers that are film forming sealants. Beware of products that contain acrylic resins, varnish resins or alkyd resins. Look on the label for these ingredients. These products do not readily soak into the wood. They leave a film that will eventually peel. If the film peels unevenly from your wood surfaces, it will become a maintenance nightmare. You will have to strip your wood in the future to add additional sealants.
Be sure to follow the instructions on all cleaning and sealant products. Hot, sunny, windy days can be the worst time to apply certain products. Some synthetic water repellents will last up to 3 years if you apply them according to instructions. I have a synthetic water repellent on my front porch that is two years old. It looks practically like new. There is no sign of mildew or algae growth whatsoever.
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Comments:
Catherine 09 Dec 2007, 20:53
Hi..........I have just had a new redwood deck built. My carpenter says he
will put pentathol on it now, and I should wait until summer to put sealant
on it. Does this sound right? Shouldn't it be sealed now before heavy
rains start? Deck was started in Sept. so wood has been around for awhile.
Carpenter says the wood is "green" now, but I'm worried about how it will
weather all the rains until next summer if it's not sealed now. What do
you advise? Thanks
AsktheBuilder 10 Dec 2007, 07:25
Catherine,
My advice is simple; please read *all* of my Deck Maintenance articles so you can discover the reasons why your carpenter is not giving you the best product. Act quickly!
Guy 19 May 2009, 06:15
Can you recommend a product??
I have not been able to find one that has everything you state. thanks, Guy
Fred F Robinson 23 Jun 2009, 22:36
I am putting plywood floor in my boat and I would like to have it last
longer then 3 years in wet weather any suggestions?
Roger 30 Jun 2009, 09:43
Fred,
Have you tried using Marine Plywood for your boat?
Barry Stone 23 Jul 2009, 23:02
I have a cedar deck approx. 2000 sq. ft. Its 5 years old. I have applied
penetrating stain on two occasions. My contractor is telling me that the
best thing to do is to rent a circular sander and sand the whole deck until
it looks new and apply another penetrating stain. I would need to do this
every two or three years to have a good looking deck. Thats a lot of
maintenance!!! Will the use of your product be ok to us over my deck which
has previously been stained? I understand that I would have to be careful
not to put to much on or I may remove the existing stain. What kind of
results might I expect???
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