Most homeowners wait until damage is visible before acting. However, several warning signs alert you well before the situation becomes critical.
1. Black or greenish streaks
The dark streaks on your roof are not ordinary dirt. It's Gloeocapsa magma, a cyanobacteria that feeds on calcium carbonate granules in your shingles. Without SH treatment, it spreads and gradually degrades your roofing.
2. Visible moss presence
Green moss indicates excessive moisture retained by your roofing. It acts like a sponge, keeping moisture against your shingles and accelerating their degradation. It's particularly present in shaded areas.
3. Gray or orange lichens
Lichens are even more problematic than moss. Their rhizines embed deeply in the shingle. Once established, they require a higher SH concentration and longer contact time to be effectively eliminated.
4. Roof darker than original
Compare your roof's current appearance with photos from when you bought the house or after shingle installation. General darkening indicates extensive organic colonization.
5. Granules in gutters
Some granules in gutters are normal. A significant quantity indicates your shingles are prematurely degrading — often accelerated by algae and moss retaining moisture.
6. Your roof hasn't been cleaned in over 5 years
Even if your roof looks clean to the naked eye, organisms establish themselves progressively. A preventive cleaning every 3 to 5 years is much less expensive than premature roof replacement.
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