07/20/2026
Moss on Your Cottage Roof? How Roof Rejuvenation Can Help Protect Your Investment
If you own a cottage along Lake Erie or Lake Ontario, you’ve probably noticed that roofs near the water tend to age differently than those farther inland. The combination of high humidity, morning dew, shade from mature trees, and frequent moisture creates the perfect environment for moss, algae, and lichen to grow.
While a little green on your roof might seem harmless, moss can gradually shorten the life of your asphalt shingles if left untreated.
Why Moss Grows on Lakefront Roofs
Properties near the Great Lakes experience unique environmental conditions that encourage moss growth:
• High humidity throughout the spring, summer, and fall
• Frequent overnight condensation and morning dew
• Reduced airflow around wooded cottage lots
• Shaded roof sections that stay damp longer
• Organic debris such as leaves and pine needles collecting on the roof
These conditions allow moss to establish itself and continue spreading over time.
Why Moss Is a Problem
Moss isn’t just a cosmetic issue.
Moss is a living plant that develops a tiny root like system that anchors the moss tightly to the roof surface making it difficult to remove without causing surface damage.
As moss grows, it acts like a sponge, trapping moisture against the surface of your shingles. During Ontario’s freeze-thaw cycles, that trapped moisture can freeze and expand, increasing stress on the roofing materials.
Over time, moss can:
• Hold moisture against shingles for extended periods
• Accelerate the loss of oils in asphalt shingles
• Enhances damage from freeze-thaw cycles during Ontario winters
• Increase granule loss
• Gradually lift shingles edges as thick mats of moss expand
• Create areas where debris and moisture accumulate
• Shorten the overall lifespan of your roof
The earlier moss is addressed, the easier it is to protect your roof from long-term damage.
What About Black Algae Streaks?
Those dark streaks that you commonly see on asphalt roofs are usually caused by algae growth!
Read the full article here to learn more about how roof rejuvenation can save your roof from moss and algae problems.
How Roof Rejuvenation Can Help Protect Your Investment