moss, mildew, lichens on roofs PRN Roofing Tuscaloosa

Moss, mildew, and goo, oh, my!

Moss, mildew, algae, fungus, and lichens are small, flowerless plants that lack true roots. They are individual plants that are composed of very small leaves that grow together.They thrive in cool, damp, shaded areas. They grow quickly and can form large carpets of green on almost any surface, including rocks, trees, branches, dirt, and roofs. Moss and their relatives are cool to observe in the forest; however, once they get on your roof, they can be a gooey mess indeed!

PRN Roofing is the best commercial roofing specialist in Tuscaloosa. Offering commercial, residential, and multi-family roofing solutions, PRN Roofing has seen moss and its relatives on roofs and knows how to rid your roof of moss. In this blog post, we’ll take a look at why moss, lichen, algae, and other small plants can be a problem on your Tuscaloosa commercial, residential, or multi-family roof. Call us today to learn more!


As mentioned above, moss loves the shade and moisture. Thus, moss is most likely to be found on roofs that are in the shade and in weather that is wet, such as in the Pacific Northwest in the United States. However, the sun is the most important factor. A roof that is always shaded is at danger of moss growth no matter what part of the United States it is located. Moss can grow on most roofing materials, including asphalt shingles, roll roofing, wood shingle roofs, and wood shake roofs.


Moss is very cute, there is no doubt about it. It’s soft to the touch, and you may fancy that you are growing a green roof, which is a roof that has grass planted on top of it. However, a green roof also has a membrane that separates the grass from the roofing material.

Moss is dangerous to roofs because it holds moisture, which creates a constant wetness that sits on your roofing material. This wetness will speed the wear of your asphalt roof shingles, and if it freezes, can take the roof granules with it and crack the shingles. And although moss does not have traditional root systems, they have to hold on somehow. Their primitive roots can penetrate your roof shingle material, affecting the longevity of your roof. Sometimes the moss or lichens on your residential, commercial, or multi-family roof can be so bad that you can’t even tell what kind of material your roof was originally made from.

The water held by moss can also seep under the shingles since moss loves to grow in the spaces between your shingles, eventually saturating the roof sheathing below. This threatens the structural integrity of your roof, as well as cause unhealthy mold growth in your attic or home.

Lichens and algae are not as thick and thus cause less damage. However, lichens and algae need the same conditions to grow as moss does (wetness and shade), and they can be a precursor to moss forming.


PRN Roofing in Tuscaloosa notes that moss, lichen, algae, and other unnatural plants growing on your roof need to be removed as soon as possible once discovered. Below are ways you can remove the moss from your roof.

  • One way to keep moss at bay is to install zinc or copper flashing. When it rains, very small bits of zinc and copper wash down your roof, which is poisonous to moss and will kill it.
  • You can brush or broom the moss off your roof if the moss growth is mild.
  • Moss-killing chemicals, or the equivalent of weed killer is an option. Home hardware stores sell granule or powder forms of this chemical to help prevent it from entering our water supply.
  • Call your local roofing contractor to help.


As you can see, any green or black that is not natural to your roof can be a problem. When you partner with PRN Roofing in Tuscaloosa for a free roofing inspection, we can determine what exactly is growing on your roof, the degree of the moss growth, and the best course of action to render the problem fixed. Give us a call today!