Exterior finishes need to possess specific characteristics such as waterproofing, weather resistance, resistance to pests, fungi, UV rays, and ease of finish restoration. All types of wood used outdoors are prone to the same problem of graying caused by UV rays, whether it's domestic or exotic wood.

To prevent this graying, it is essential to protect the wood with a colored exterior product. Staining is the best way to protect against UV rays. It is important to follow the manufacturer's recommendations for maintaining the product used.

If a product without any color pigment is used, the wood will quickly undergo color changes and turn gray in the months following application. The process will then need to be started over, including cleaning, sanding, and applying a new finish.