On fences, sealers will show wear in about 2 years and will need to be re-sealed in 3. Stain will show wear in about 4 years and need maintenance in 5. On decks, vertical surfaces will wear the same as fences, while the horizontal surfaces (floor, handrails, stairs) will last 1-2 years with either stain…
With proper chemicals and professional cleaning, and power-washing, the grey can be removed and the wood will look like new after a good stain and seal.
The discoloration is a deterioration of the wood as a result of a combination of dirt, bacteria, decay, and fading from the sun.
The spots are spores of bacteria growing in the pores of the wood. Wood is food for bacteria, but coating it retards its growth.
In most circumstances, peeling is the result of improper application of a coating, over-applying the product, or using a product that didn’t penetrate into the surface of the wood.
Unprotected wood, when exposed to weather, will decay at an accelerated rate and will shorten it’s life. When you walk over the surface of an unmaintained deck, you are bringing bacteria, dirt, and algae back into your home.