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Is Moss Bad for Your Roof?

There is nothing better than a sparkling clean roof, with clean guttering and everything in order. While it may be a roofer’s dream, in many cases, home and property owners struggle with keeping their roofs in tip-top shape. We come across many roofs with lichen, moss, and mould – it’s only natural for debris and bacteria to build up over time. But is moss bad for your roof?

To the untrained eye, moss may look like a furry benign build-up; however, as any roofing contractor will tell you, moss or lichen can be extremely damaging to the structure of your roofing.


The best thing for your roof is to be clean and free of any build-up, debris, and moss. Even if the build-up is purely cosmetic, it is still not good. At the very least, no one wants to buy a home with a furry green roof nor come home to one at the end of the day. Think moss or other build-ups on your roof is only a problem for guttering or visual appeal? Think again.

Mould, moss and lichen, love damp and warm environments and roofs present an ideal breeding ground. Blocked guttering and built-up debris on your roof can prevent water from draining off of it. If the water fails to drain, it starts to pool on top of the roofing material, causing leaks moisture damage and mould.


Is moss bad for your roof? Yes. Here are a few reasons as to why it’s not good for your roof or roofing materials: 

Is Moss Bad for Your Roof?

Firstly, any build-up of debris is going to trap water and moisture on the roof. The more moisture trapped on your roofing and guttering, the extra wear and tear your roof is going to experience. Moss grows into a thick grass like patch roofing materials and loves soaking up moisture. If it begins growing into your roof cavity and guttering, it will only bring more problems.

Typically, when it rains, water will hit your roof and flow down across your roofing tiles or sheeting and down into your guttering. The pitch of your roof and arrangement of materials ensures a smooth, even flow, and that water doesn’t pool as it makes its way across your roof.

When moss builds up on your roof, it collects water and keeps it trapped in the same area. When moisture pools, it can find its way through even the most minor gaps in your roof. Once the water begins to find its way into your roof and ceiling, it opens up a whole host of moisture problems.

To further understand why is moss bad for your roof, it is important to note that moss has tiny root-like protrusions which will get into small spaces and cracks in your roofing material. As they dig in under tiles, they can force them to move or warp. For our customers in Canberra, where temperatures can drop below zero in the winter, the water held in by the moss and lichen can freeze and cause cracks in your roof tiles. When the tiles crack, it opens up more spaces for moss and water to penetrate. If these tiles continue to go unchecked, you could end up with serious infiltration problems with your roof.


Whether you have slate, terracotta, or any other material up on your roof, moss, lichen, and mould can cause serious problems. As slate tiles, especially synthetic slate, are coated in a protective layer, it takes years for the coating to wear out and moss to grow. But nonetheless, when the slate becomes porous and you see early signs of growth on your roof, it is best to nip it in the bud.

Moss on Roof Tiles Is It a Problem


When it comes to cleaning and roof maintenance, it is best to leave it to the professionals. Working on roofing is inherently dangerous and challenging. Removing the moss yourself can be more expensive as it can require specialist cleaning chemicals; not to mention, DIY projects sometimes cause more harm than good.

Roofing professionals, such as the team at Vertec, will identify the types of growth present and assess if any damage has occurred. After the types of growth have been identified, we can then take the best course of action to clean your roof and remedy any damage done. Cleaning processes during our roof cleaning service can include:

  • Low-Pressure Water Cleaning: High-pressure solutions can be harsh on your roof. Using a low-pressure cleaning method will remove the growth from your roof without causing further damage. Manual scrubbing is also employed to get rid of those more stubborn growths.
  • Chemical Solutions: In some situations, chemical solutions can be used to clean the debris and growth depending on the material your roof is made from.


So, is moss bad for your roof? Yes. At the end of the day, overgrown moss, lichen or other bacteria can lead to a leaking roof. Whether you’ve noticed a build up of mould and need your roof professionally cleaned, or you now need leaking roof repairs in Canberra or Sydney, we’ve got you sorted.

Whether you need expert roofing services in Sydney or Canberra, Vertec Roofing is at your disposal. We have repaired our fair share of mossy roofs with over 20 years of experience in the roofing industry. For more information on our Canberra Roof RepairsSydney Roof Restoration or any other roofing service, contact our team today.

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