The natural weathering of wood is a complex combination of chemical, mechanical, biological, and light-induced processes which interact to change the appearance and structure of unprotected wood exposed to the elements. Within two months of outside exposure, wood begins to turn gray. Dark wood will become lighter, light woods eventually become darker, surface checks, raised grains, cupping, warping and cracks eventually occur as wood continues to weather.

These processes are caused by the decomposition of wood components by moisture, sunlight (ultraviolet radiation), temperature, oxygen, atmospheric pollution and airborne fungal spores. These factors combine to physically and chemically attack wood lignin, the chemical structure which holds wood together. Once wood surfaces turn gray, the surface continues to slowly erode.

The forces of weathering can be devastating to wood. Moisture from rain, snow, and dew, are quickly absorbed by unprotected wood causing it to swell. And then heat from the sun dries and shrinks wood. These cycles of wet and dry swelling and shrinking causes wood to warp, cup, crack and become discolored.
 

Since decks are horizontal surfaces, they hold water, snow and dew for longer periods of time, which accelerates damage. The prolonged dampness attracts dirt from atmospheric pollution and airborne fungal spores. Decks are subject to 40 to 50 percent more U.V. radiation from sunlight than comparable vertical surfaces. This causes more thermal stress to decks than most wood surfaces.

The temperature difference between the sun exposed top of the board and the shaded bottom can be as much as 50 degrees Fahrenheit. In addition to this, decks are subject to foot traffic and physical wear and tear.
 

Over 80% of decks are constructed with pressure treated wood, usually pine, that have been injected with chromate copper arsenate (OCA), a chemical that protects wood from rot and insects. But pressure treating wood does not give it weather protection. In fact, according to the manufacturers of OCA lumber, it actually makes wood more porous and susceptible to water damage. And without proper care, treated lumber can deteriorate from the elements. Sunlight rapidly grays unprotected wood, and moisture promotes decay, as well as mold and mildew growth.
 

In some parts of the country, cedar and redwood decks are popular. In the past, cedar and redwood came mainly from old growth trees that were primarily heart wood. This part of the tree contained high levels of resins, and oils which were more naturally resistant to decay, insects and water damage. However, most of the cedar and redwood which goes into wood construction today is from the sapwood (outer part) of younger second growth trees, which is much less resistant to decay. Since dry wood can’t rot, using a product with the highest water repellent efficiency will offer the greatest protection.

Protection from termites and insect infestation is best provided by spraying the wood with commercially available solutions of borate and water. This is more effective and safer for the applicator and the environment than using products which contain wood preservatives (toxic fungicides and insecticides) that must by registered with the EPA.
 

DEFY is formulated to deeply penetrate wood; if too little is applied it will fade more quickly. If too much is applied, or the surface is not properly prepared, the product may form a film and eventually peel. Prepping wood to increase porosity will allow it to absorb more DEFY. Better penetration allows DEFY to protect wood longer and still maintain its attractive finish.

It is recommended that you schedule a light maintenance coat every 12 - 18 months for flat horizontal surfaces and approximately 3 - 5 years for vertical surfaces, such as spindles, log homes, etc...  You will need approximately half the material that you used on the initial coating. Maintenance is directly related to application. To achieve optimum performance, and reduce the level of maintenance, carefully follow the recommended procedures for cleaning and preparing wood prior to the initial application of DEFY wood finish. Manufacturers guidelines for optimum performance.
 

It is equally important to give an initial thorough cleaning of the wood with a garden hose to remove dust and dirt. A weak solution of TimberWash may be used to remove any graying or mildew that has occurred. If needed, TimberBrite may be used to remove stubborn stains, or for use on cedar and redwood. Rinse thoroughly and allow wood to dry completely. Apply one thorough coat of finish to restore color and water repellency to the wood.  As exterior wood ages, it can darken, so the color of a maintenance coat may be enhanced, or darker, than the original application. This is a normal process and the finish will lighten with further exposure.