I have light grey asphalt shingles and over the last two years dark steaks running vertically have changed the colour to a dark grey on the north side.The shingles are not shaded by trees and don't have moss on them.They also appear to be in good shape except for the streaks.The streaking is as if someone had thrown blobs of dark liquid on the roof and it then ran down to the eavestrough staining the shingles in the process.Have you any ideas about what this is and what I could do to remove the staining?
Answer:
There is a magnesium strip you can order through your local lumber yard. You install it under the uppermost layer of shingles so half of the 1" width is exposed. As roof run-off flows over it, it cleans off the black stain and keeps it clean.
Courtesy of Ren Molnar, Construction Consultant at HomeFocus.com. I can also be reached at (613) 748-3003 and Home Focus – The Radio Show is broadcast live 8 to 10 A.M. (Ottawa, Ont. time) on Saturdays on www.cfra.com. In the interests of retaining credibility and in fairness to all, I cannot recommend prices, people nor companies for various projects.
