Q. I live in a mansard-style home with shingles down the entire second floor. On the east side of the roof, lichens have established quite a home. Without ruining the fiberglass shingles, how do I ...

Dear Jerry: Our house was recently painted, and the contractor told us that the roof shingles on the north side have mold that should be removed. The house was built in 1966 and has the third roof on ...

QDEAR TIM: My roof needs cleaning. It's a newer asphalt shingle roof, but parts of it are covered with moss, lichens and algae. Is a pressure washer a good tool for cleaning roof shingles? Will it ...

Q. The roof on our cottage has been developing a mossy or lichen coating for the last several years. It doesn't seem to wash off easily, and I'm wondering if it is hurting the shingles. What can we do ...

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: Have you ever heard of roof-washing? I had an offer to wash my roof and remove lichen, mold and algae, for $900. The man claimed the lichen will ruin the roof, and he has chemicals to remove it.

Q I have a six-year-old asphalt shingle roof with a patch of moss on the north side. Is there a safe and effective way to remove it? A It's unlikely to be moss. That usually takes longer than six ...

Q: I have a 10-foot-by-12-foot tool shed in a shady area with a roof covered with unsightly lichen. Can you suggest any relatively simple way to remove it before I paint the shed? A: Ah, yes, lichen ...

Q. I have a 10-foot-by-12-foot tool shed in a shady area with a roof covered with unsightly lichen. Can you suggest any relatively simple way to remove it before I paint the shed? A. Ah, yes, lichen ...

Q: We have a “green roof” that is not meant to be green. Moss (I guess it is moss) is collecting on one side of the asphalt roof. The roof is otherwise in good shape. What I have learned so far is ...