Deck Sealer – Epoxy Fortified

DEAR TIM: I love my wood deck but hate to care for it. I have tried many deck sealers and they all turn black or green in short order. Those that do seem to perform better than others suffer significant fading. Is there a miracle penetrating deck sealer that will last for three or possibly four years? What is the best way to clean my wood deck before applying the sealer? Christine R., Roswell, GA

DEAR CHRISTINE: Up until recently your quest for the fabled miracle deck sealer might have been more difficult than the quest for the Holy Grail. Millions of homeowners including yourself and professional deck restoration companies have longed for a product that will look superb for two and even three seasons in a row. But just about every product has led to a certain degree of disappointment. When you begin to look closely at the problem, one quickly discovers that there are many reasons why many common deck sealers fail so quickly.

Many common deck sealers are oil based. The primary water repellent ingredient in many of these products is a natural oil. The oil might be linseed, vegetable, tung or even a modified animal fat. These oils do indeed repel water, but they attract mildew and algae. In fact, these oils are delicacy foods for these black and green organisms. The deck sealer manufacturers have known this for many years. They add chemicals - mildewcides and algaecides - to the sealers that poison the organisms and inhibit their growth. But ultraviolet (UV) sunlight, rain and snow-melt degrade these chemicals. Once this happens, the mildew and algae begin to feast on your deck sealer.

Wood decks are also exposed to the harshest conditions of just about any other horizontal or nearly horizontal building material at your home. Concrete drives, patios and sidewalks are far more durable than wood. Roof shingles typically have ultra-durable ceramic glass granules that protect them from UV and water. The wood that is laid flat to create the deck surface and handrails absorbs the full impact of the destructive UV rays during the middle part of the day. This same flat wood does not easily shed rainwater. Water can sit on the wood or, in the worst cases, soak into unprotected wood via small or large cracks in the wood surface. Wood siding and trim on the walls of a typical home never has to put up with this type of abuse.

Years ago, I discovered several high-performance synthetic resin deck water repellents that worked much better than other brands. The synthetic resins are not food for mildew and algae. But recently a vast improvement has hit the marketplace. You can now purchase an epoxy fortified synthetic resin deck sealer that shows enormous promise. Test results show it is highly resistant to fading. The epoxy helps to bond the sealer to the wood fibers greatly extending the service life of the sealer. An added benefit is the product is a penetrating water repellent. The epoxy fortified water-based product soaks deeply into wood instead of laying on the surface, where it might peel after a year or two.

Cleaning a wood deck is very important before sealing it. The cleaning process removes dirt, mildew, algae, and sun-damaged wood fibers. I am not a fan of pressure washing, even at lower pressures. This water blast can and does erode soft lighter colored spring wood from each decking board. If your deck is made with chromated copper arsenate (CCA) lumber, pressure washers may pose an additional danger. The pressure washer may dislodge CCA impregnated wood fibers and transport them to the soil around your home.

Perhaps the best cleaning method is a combination of oxygen bleach and a small amount of old-fashioned elbow grease. Oxygen bleach is a non-toxic powder that mixes with water. Beware as not all oxygen bleach products are the same. Many contain ingredients made off-shore that might be not as pure as USA made ingredients. What's more, not all products contain the same amount of active ingredient. Some low-priced products contain vast amounts of filler. The high performance oxygen bleaches typically cost more.

The active oxygen ions released after the powder is mixed with water vigorously deep-cleans the wood. Typically, the oxygen bleach solution is liberally applied to the wood surfaces and allowed to bubble for 10-15 minutes. If it soaks in or starts to evaporate, add more solution. After waiting, lightly scrub the wood with a scrub brush on a pole and rinse with a garden hose. If you use the water-based epoxy fortified sealer, you may be able to clean and seal your deck in the same day.