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Common Water Issue in BC
Moss or Algae Growth on Roof
Moss growing on roof shingles is a common sight on BC roofs, particularly on north-facing slopes and shaded areas. While moss itself is a cosmetic issue, it traps moisture against the shingles, accelerating deterioration and increasing the risk of roof leaks. Moss growth also indicates chronic dampness that may affect the roof's performance and lifespan.
Possible Causes
- •Shaded roof areas that stay damp after rain
- •North-facing slopes with limited sun exposure
- •Tree overhang dropping debris and creating shade
- •Asphalt shingles beyond mid-life with granular loss
- •Poor roof drainage with standing water on low-slope areas
Recommended Steps
- 1Have moss removed professionally — do not pressure wash as it damages shingles
- 2Install zinc or copper strips at the ridge to inhibit regrowth
- 3Trim overhanging tree branches to increase sun exposure and airflow
- 4Schedule a roof inspection to check for hidden moisture damage beneath moss-affected areas
Need Professional Help?
Don't let a small leak become a big problem. Contact LeakInspections.ca — a division of Anyleak.ca and Leak.ca — for expert diagnosis.