Why do Orlando driveways turn black, green and orange?
Orlando's heat, humidity and long wet season are ideal for algae and mildew. Concrete is porous, so growth takes hold in the surface and shows up as gray, green or black patches. Shaded areas and spots near downspouts and sprinklers go first.
Orange or brown streaks usually have a different cause. Many Central Florida irrigation systems use well water that contains iron. As it dries on concrete, it can leave rust-colored stains. Rust needs a specific treatment and may only lighten rather than disappear.
Tire marks, oil drips and fertilizer stains are also common. Oil that has soaked in for months is hard to remove completely, and we will tell you honestly what to expect.
