Why do wood decks and fences turn gray and green here?
Sun, rain and humidity break wood down fast. Ultraviolet light fades the surface to a silver gray. Moisture and shade feed mildew and algae, which show up as black spots, green film and slippery boards. Fences along canals and under trees stay damp longer and grow mildew sooner.
Problems we often see
- Slippery green boards on shaded steps and landings.
- Black mildew spots on fence boards and rails.
- A gray, dry surface where old sealer has worn away.
- Rust marks from sprinkler heads that spray the fence.
- Soft or cracked boards that need replacing, not cleaning.
Washing cannot fix rot. If boards feel soft, we will tell you so you can plan repairs.

