Does Moss Cause Damage To Roofs?

WHAT IS MOSS?

Moss is a small, non-flowering plant from the division Bryophyta. It thrives in damp, shaded environments and can grow on various surfaces, including soil, rocks, and rooftops. Moss lacks true roots, stems, and leaves but has structures that perform similar functions. It absorbs water and nutrients directly through its surface, unlike plants with vascular systems. Moss appears as green or yellow-green mats that spread horizontally because it cannot grow tall. Further on we will discuss, does moss cause damage to roofs.

Moss reproduces through spores, an ancient method that predates seeds. Spores are lightweight and easily carried by wind or water. When they land on a suitable surface, they begin to grow into new plants. Moss plays a crucial role in ecosystems by stabilising soil, providing habitats, and retaining moisture.

HOW MOSS THRIVES AND EXPANDS

Moss spreads through spores that settle on damp, debris-filled surfaces. Moisture is essential for its growth, as moss depends on water for nutrient absorption and reproduction. Shade further enhances its ability to thrive. Without direct sunlight, moisture evaporates slowly, creating ideal conditions.

As moss grows, it traps debris, creating a nutrient-rich base for expansion. This self-sustaining cycle allows it to spread rapidly and form dense mats. Moss’s reproductive strategy of producing numerous spores ensures its ability to colonise new areas, particularly where shade, water, and organic material are plentiful. The fact moss can expand fast reflects upon the question, does moss cause damage to roofs.

WHY REMOVE MOSS?

Moss may seem harmless, but it can cause significant damage to roofs. When asking, does moss cause damage to roofs; one responder shared that moss on his roof blocked water flow, leading to leaks. Ken Kellman from within the same 2017 article noted that moss forms dams that force water under tiles, causing wood to rot and jeopardising the structural integrity of the roof.

Johannes Enroth has observed that moss on concrete tiles freezes and thaws, eroding the edges of the tiles. Additionally, moss traps debris, which allows larger plants to take root, further adding to the structural stress. While vinegar (50%) can effectively remove moss, early intervention is key to preventing expensive repairs. It is clear that regular maintenance is essential to protect roofs from moss-related damage.

BAC50 BIOCIDE AND SODIUM HYPOCHLORITE TREATMENT

BAC50 biocide and sodium hypochlorite are both effective in treating moss on surfaces like roofs. These chemicals work in different ways to control and prevent moss growth when applied correctly. We are able to use both of the following chemicals for roof maintenance, and we also use a steam cleaning machine for our Roof Cleaning Service.

BAC50 Biocide targets the cell structure of moss. It disrupts the integrity of moss’s cell membranes, causing it to lose its ability to retain water, leading to dehydration and eventual death. BAC50 is often preferred due to its long-lasting effects. It not only eliminates visible moss but also targets spores, reducing the chances of future infestations. BAC50 is more environmentally friendly as it naturally breaks down over time.

Sodium Hypochlorite is a strong oxidising agent commonly found in household bleach. It disrupts the chemical processes within moss cells, particularly affecting chlorophyll and other vital components. The chemical causes the moss to lose its green colour and die rapidly. Sodium hypochlorite is effective in killing moss but can have negative effects on surrounding plants and surfaces, especially if not diluted properly. Although it is a quick solution, it doesn’t prevent regrowth as effectively as BAC50, meaning reapplication may be needed.

Both chemicals are effective but serve different purposes. BAC50 offers a longer-term solution by preventing future growth, while sodium hypochlorite provides faster but temporary results. In either case, it is important to apply these chemicals carefully to avoid harming other plants or the environment. Regular maintenance is still necessary to keep moss from returning. We discuss more on roof cleaning chemicals here.

SCRAPING MOSS OFF A ROOF

Scraping is a popular method for removing moss, but it may not eliminate all the spores. Moss spores are tiny and lightweight, making them easily dispersed during the scraping process. When scraping moss off, many spores will remain on the roof’s surface, particularly in crevices and between tiles where the scraper may not reach. According to research on moss removal techniques, scraping can physically remove much of the moss, but it often leaves behind the spore bank, allowing regrowth if conditions remain favourable (Jones, 2013). While scraping reduces the visible moss, it may not fully prevent its return unless further treatments are applied to target the spores.

USING STEAM TO REMOVE MOSS FROM ROOFS

In contrast to scraping, steam is a more thorough method for controlling moss growth. Steam cleaning works by applying high-temperature steam to the moss, loosening it from the surface. The heat also damages the moss’s cellular structure, causing it to die. More importantly, steam can penetrate deeper into the roof surface, reaching areas where spores are embedded, thus killing them as well. Studies have shown that steam treatment significantly reduces the number of viable moss spores remaining on surfaces (Clement et al., 2016). Since spores are more sensitive to heat, steam is a more effective solution for preventing moss from re-growing, as it addresses both the visible moss and spores hidden in crevices.

DOES MOSS CAUSE DISCOLOURATION TO ROOFS?

Moss does not directly cause discolouration of roofs. Unlike lichens, moss lacks the acids or pigments that can stain surfaces. However, moss can trap moisture and debris, creating conditions that encourage algae or fungi growth. Over time, these organisms can leave stains on the roof. While moss itself does not permanently discolour roofs, it can contribute to conditions that lead to staining. Regular cleaning ensures that moss doesn’t harm the roof’s appearance or functionality, maintaining its visual appeal and structural integrity.

By understanding moss’s nature and using the appropriate removal methods, homeowners can protect their roofs from damage. Regular maintenance, along with targeted treatments, is essential to prevent moss growth and the issues that follow.