What could be the caused of this.
It was light rain when the photo taken.
It was above the garage. I don’t think it was a ventilation problem
What could be the caused of this.
It was light rain when the photo taken.
That is a fungal, bacterium or algae type growth. Should be cleaned for the long term health of the roof shingles. It will cause damage over time and reduce the life span of the shingles.
(note: algae does not do much damage, no red alert. I still recommend cleaning because other type of growth can follow where there is food)
3 Likes
Do you have a pic of the entire roof? Is there a tree branch hanging over the roof?
2 Likes
This is a good article. You can dive in deeper on different type of staining for further insight as needed and match up with what you observed.
https://inspectapedia.com/roof/Roof_Stain_Diagnose_Remove.php
2 Likes
Makes sense about the fungal, bacterium or algae growth. A tree does overhang some of the roof and must be spreading.
Thanks!
3 Likes
Pollen, sap, organic matter can precipitate off trees and discolor building materials.
1 Like