Algae On Exterior Of House - November 17th 2006

Algae On Exterior Of House

Q: Our home is 15 yrs old and in excellent condition except for soffits that when viewed from the outside, appear greyish black in some areas, especially above the windows. The attic looks moisture free. We tend to open our bedroom windows for fresh air, especially at night. What is causing the problem, and how can we fix it?

A: The warm moist air escaping from your open windows during the winter months causes condensation to form on the soffits hence the dark algae formation. Warm air exiting from the windows allows the high relative humidity in the air to move upwards coming in contact with the cold under eave soffits hence the condensing causing the black spore growth called algae. To remove the staining, wash the area with my Shell Busey Home Cleaning Formula and rinse well. The cleaning formula is available at most Building Supply stores or call 604 542 2236 for availability in your area.