Why do Manchester houses go green, grey and streaky?
Frequent rain, damp air and little drying sun give algae and lichen an easy run. North-facing walls and shaded gable ends are the worst hit. On a terrace, the back wall in a narrow yard often stays damp for much of the year. Render shows green growth quickly, while brick takes on a dark, patchy look.
Overflowing gutters and leaking downpipes add black streaks under the eaves and down the wall. White uPVC dulls and picks up traffic grime on streets with heavy traffic. None of this is dangerous for the house in the short term, but growth holds moisture against the wall and makes a well-kept home look tired.
