Q. Many roofs in my neighborhood, mine included, are covered with black streaks. What's causing this to happen, and can the roofs be cleaned? I'm able to walk on my asphalt shingle roof with ease, but ...

Dear James: Our 3-year-old light-colored roof already has dark stains over most of it, except for near the chimney. Why is that, and how can we stop the staining from getting worse? — Phil R. Dear ...

Q: Lately I’ve noticed dark streaks on my roof shingles as well as other roofs in the neighborhood. The roof is about 12 years old and is in good condition. Can you tell me what the streaks are and if ...

Dear James: My house has a light-colored roof and it needs to be replaced. It has always had a problem with dark stains on it. What is causing the stains and how do I avoid them on the new roof? -- ...

My roof has skid marks. And lichens. Next thing you know, it could grow a mossy beard. What's going on here? And more important, what can I do about it? You might be wondering the same thing, if your ...

Q: On many roofs with asphalt shingles I notice black streaks. New light-colored orange-red asphalt shingles were installed on our roof about six years ago, and now I notice the dark streaks forming.

Shingles with this feature will come with a warranty against algae discoloration, while standard shingles will probably exclude coverage. That is the case with GAF, which manufactures Sentinel ...

DEAR TIM: Many roofs in my neighborhood, mine included, are covered with black streaks. What’s causing this to happen, and can the roofs be cleaned? I’m able to walk on my asphalt shingle roof with ...