Can You Identify What’s Growing on Your Roof?

June 11, 2018/Eddie Guevara
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There are four types of growth to watch for:

  1. Algae
  2. Lichen
  3. Fungus
  4. Moss

Algae Growth

  • Extensive Algae growth – in both green and black.
  • Different colors are evident.
  • Dark appearance is a protective layer the algae have developed to protect itself from damaging UV rays.
Algae Growth
Algae, Lichen, Fungus

Algae, Lichen, Fungus

  • Evident in this image are Lichen, Fungus & algae.
  • Notice the vent metal has inhibited growth. This observation is what initially prompted researchers to finding metals which prevent algae growth.
  • Note the algae-free surface on dormer roof. This is due to exposure to the sun, allowing that portion of the roof to dry faster.

Algae Growth

  • Extensive algae growth.
  • The area below the window is free of algae due metal flashing… run-off of the metal inhibits growth and algae.
  • Algae predominantly grow from the bottom up, due in part to the amount of time water is on the roof.
ALGAE GROWTH 2
LICHEN & FUNGUS GROWTH

Lichen & Fungus Growth

  • Fungus is predominantly at the shingle edges and keyways.
  • Left to grow may eventually damage the shingles by lifting them and further inhibiting water run-off.

Moss

  • Moss due partly to low slope, shady location, organic material & exposure.
  • Water is retained on the roof; thus essentially aiding the growth.
  • Organic material needs to be present for growth or moss cannot take root.
MOSS
Geographical Predominance
  • White: Very Low Algae, Moss, Lichen and Fungus Growth
  • Yellow: Low Alga, Moss, Lichen and Fungus Growth
  • Red: Severe Algae, Moss, Lichen and Fungus Growth
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Eddie Guevara

Eddie Guevara

Born in Naples, Eddie is a devoted husband and father of two who has built his career with Kelly Roofing from the ground up. After years of leading the company’s operations division and elevating the Project Administrator role through his passion for technology and efficiency, Eddie now serves as President of Kelly Roofing. In his role as President, Eddie oversees the company’s strategic direction, ensuring continued growth, operational excellence, and a commitment to innovation across both office and field operations. As a member of the Executive Leadership Team, he plays a key role in positioning Kelly Roofing for the future while staying deeply connected to the company’s day-to-day success.