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 ...

Q: About algae on shingle roofs. ... Is there a best time or two during the year to apply a recommended cleaner with a garden sprayer? A: Although algae stains are unsightly, the stains do little to ...

Days ago, Jerry stopped by my website, AsktheBuilder.com. He reads my column each week in his local paper and was perplexed by algae growth on the exterior of his home. Jerry hales from Chesterton, ...

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 ...