What sun and dry air do to fence wood
A wood fence in Rancho Cucamonga turns gray because sunlight breaks down the wood surface, and the dry inland air speeds up how rough and cracked it gets. The city sees sun on most days of the year, and the Santa Ana winds that come through the passes from the desert bring the lowest humidity of the year to Southern California.
The damage starts at the surface. About a fifth to a third of wood is lignin, the natural glue that holds the cellulose fibers together, and ultraviolet light starts breaking it down within hours of exposure. The change is invisible at first, but it weakens how well any finish can grip. As the lignin washes out, loose gray fibers are left behind, and in arid climates the wood often takes on a silvery-gray sheen.
Signs your fence needs attention
- Boards that have turned gray or silver.
- Fibers that rub off on your hand.
- Checks along the boards and cracks at the ends.
- Dark blotches of mildew on the shaded side.
- A previous stain or paint that is flaking or has worn through.
Badly weathered wood with loose fibers on the surface cannot hold paint or stain, which is why cleaning comes before color.