Many owners of houses and outbuildings face the problem of moss on the roof. Still, opinions are divided: some are sure that moss must be removed, while others favor not touching it and even encouraging it.

Clearing the roof of moss or leaving it as is a difficult decision for the owner. Some argue that if moss is not regularly removed, this can damage the roof and shorten the life of the roof, while another position is that cleaning will lead also lead to damage of roofs. Let’s examine the disadvantages and advantages of the “furry phenomenon” on roofs and consider whether you must purchase a roof scraper or if the moss is harmless.

Why do Mosses Conquer Roofs?

And indeed, why do these shade-loving and moisture-loving plants (bryophytes) choose roofs as their new home? Mosses are unpretentious, and rough surfaces (soft tiles, slate) are excellent for their growth; they are easily able to stick to roof tiles and the rain water provides ample nutrients for the moss to grow.

They don’t particularly need soil; bryophytes have an ascetic approach to nutrition, and no other competing plants are on the roofs.

The spores are carried upward by the wind and germinate under favorable conditions. These perennial plants do not have a root system. Instead, many bryophytes form rhizoids these are like thin threads. With the help of rhizoids, mosses obtain food and water and also attach to the ground, stones, rocks, and other surfaces that are not particularly suitable for the growth of different plants.

Nature has also endowed mosses with the ability to absorb water over the entire surface of the plant body. Therefore, they can live almost anywhere humid, even on roofs. Tenacious spores take root without problems in shaded and damp areas of the roof.

Why You Need to Clean Moss from Your Roof

Is it worth depriving the plant of such a favorable habitat, or is coexistence possible? Experts are confident that roof moss leads to several negative consequences.

  • Cosmetic problem: an overgrown roof is unsightly. It looks unkept and untidy.
  • Moss retains water and dampens roofing materials, which can lead to rotting. During the winter season, water retained by moss freezes in microcracks. When this water freezer, it expands which can cause cracks and destroy the bitumen base, which becomes even more fragile in cold weather.
  • Mosses contribute to the development of fungus and mold and the accumulation of plant debris on the roof.
  • Moss can roll down into the guttering and cause it to get blocked. Blocked gutters can also lead to overflowing and water damage.
  • Moss growth disrupts the tightness of roof joints. Under the pressure of moss, the corners of the tiles can peel off, lifting the neighboring ones in places where they overlap. Over time, the integrity and strength of the roof decrease, which entails possible leaks.
  • A continuous cover of moss disrupts the thermoregulation of the roofing “pie,” harms the home microclimate, and allegedly shortens the service life of the tiles.
  • Moss is food for some invertebrates. Insects live in it;
  • Birds peck moss and, at the same time, injure the roof tiles.
  • Dead mosses turn into dust, then into nutritious organic matter, suitable for colonizing other plants.

As you can see, the moss on the roof has several unpleasant consequences. Accordingly, it needs to be disposed of on time.

How to Clean Moss

If you are not afraid of working at dangerous heights, you can clean the moss yourself. The most budget friendly option is manually removing moss with a scraper or brush. Then, the roof is washed with a chemical. However, this work will take a long time and require significant physical effort. It is not easy to scrape the roof and sweep away debris while standing on a ladder, and the result will not be perfect; particles of moss and spores will remain. After a year, the cleaning will have to be repeated.

Removing moss off the roof using a pressure washer. Using a powerful pressure washer will quickly remove thickets of moss and dirt just remember the water must be directed only from above (from the ridge) and down along the slopes. Otherwise, you risk the chance of water going under the tiles and causing water damage to your roof. You cannot clean the roof standing on the ground; you must climb to the top and this poses a seriously health and safety risk. Only consider climbing on your roof if you have had training working at heights. It is worth remembering that a strong stream of water under powerful pressure can demolish basalt or slate roofing tiles. As a result, it will remain without a protective layer because The coating is responsible for the roofing color and protects it from the elements.

Using chemicals to prevent the growth of moss. The solutions are applied with a brush or sprayed onto a moss-covered roof in dry weather (this is important because you dont want the solutions to be diluted by rainwater). These chemicals will make the tiles unsuitable for plant life for short period between 6months-3 years. Here are the chemicals

  • spraying with 5% copper sulfate;
  • Sodium Hypochlorite
  • DDAC (Didecyldimethylammonium chloride)
  • BAC50 Benzalkonium Chloride

Preventive treatments on clean roofs should be carried out regularly. To prevent moss growth, you must spray the house with chemicals every 6months – 3 years depending on what chemical you use.

Installation of copper strips under the ridge. Some experts claim that rainwater, thanks to the strip, will be saturated with copper ions. This rainwater flowing down the roof slope has a detrimental effect on roof because copper inhibits mosses


Moss can damage your roof, so you need to remove it. You can use special tools or call specialists to do this. It will protect the roofing covering for several years.



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