Keeping your roof clean and free of moss not only enhances its appearance but also plays a crucial role in preserving its structural integrity and performance. This article provides valuable advice and practical tips on effectively cleaning roof tiles, removing moss, and safeguarding your roof for years to come.
Over time, as a roof ages, it's natural for dirt, moss, algae, and other vegetation to accumulate on the surface of the tiles, in the interlocks, and within the gutters.
Moss and lichen thrive when dirt and debris settle on roof tiles, originating from sources such as nesting birds, loose vegetation, and airborne dust particles. These organisms typically flourish in shady and damp areas, making their growth more likely during winter months, in the shade of nearby trees, or on roofs with lower pitches that don't shed water as quickly. However, moss and lichen can grow almost anywhere and under various conditions, so their presence is not limited to these factors alone.
In short, yes. If left unaddressed for extended periods, an accumulation of moss, lichen, and other vegetation can lead to several issues. First, moss absorbs moisture and retains it even after rainfall has stopped. Consequently, tiles covered in moss remain damp, creating an environment where clay tiles, in particular, are more prone to delamination. Delamination is where the clay surface separates from the main body of the tile. In extreme cases, roofs covered in a thick layer of moss can significantly increase in weight due to retained water, potentially posing structural concerns.
Additionally, moss can grow within the joints or interlocks of the tiles, causing two major problems. Firstly, it can block the interlocking channels, preventing them from functioning as intended and potentially allowing water to penetrate the sub-roof. Secondly, as moss obstructs these joints, it significantly reduces the tiles' ability to "breathe" and maintain proper airflow, potentially leading to damp conditions within the roof space during winter and overheating in the summer.
Moss also tends to thrive on mortar, often resulting in excessive growth around ridge tiles. This growth can cause damage and cracking in the mortar as it penetrates the cement. Significant moss growth at the ridge may indicate inadequate ventilation in the roof space, where rising hot air becomes trapped, creating ideal conditions for moss to flourish.
Regular roof cleaning is essential to prevent moss and algae build-up. While there is no set standard, conducting an annual visual inspection to identify potential concerns and undertaking necessary remedial work is advisable. Accessing the roof every three to five years for maintenance should suffice, although shorter intervals may be necessary if your roof is heavily shaded or consistently exposed to damp conditions throughout the year.
Before attempting any roof cleaning yourself, it's important to consider whether you should seek the assistance of a qualified professional. Roof work carries inherent risks, and it is always recommended to use appropriate equipment to safely access all areas. If in doubt, it's best to consult a local roofing specialist to perform the task for you.
Avoid walking on roof tiles whenever possible, as even if they don't break under your weight, they may develop hairline cracks that go unnoticed. These cracks can expand during freeze/thaw cycles, resulting in tile breakage later on, typically during winter.
When cleaning a roof, it is crucial to avoid using high-pressure jet washers. The forceful spray from such equipment can damage the tile finish and strip away colour from concrete tiles. Additionally, high-pressure water can seep into the interlocks and headlaps, potentially causing water ingress. If a pressure washer is used, it should be set to low pressure and directed from the apex of the roof downwards, never upwards, to prevent water from entering beneath the laps of the tiles.
To remove moss and algae from roof tiles, a trowel or stiff brush can be utilized. This task is best performed on a dry day when the moss is less moist and more easily dislodged from the tiles. After removing moss and algae, consider applying fungicides and anti-moss treatments specifically designed for roofs. These products are available at most DIY stores, but we as a manufacturer are unable to advise on adequate products. It is essential to carefully follow the instructions and take any necessary safety precautions. However, keep in mind that these treatments are not a permanent solution, and ongoing monitoring and maintenance will still be required.
While cleaning your roof, take the opportunity to inspect for any broken tiles that require replacement. It is advisable to promptly replace any damaged or cracked tiles to preserve the roof's integrity and prevent moisture from entering the roof space.
We often receive enquiries from homeowners regarding the possibility of painting roof tiles, particularly in the case of older properties with faded concrete tiles. Although some companies offer roof painting services, we generally advise against it. Applying a light covering of paint, known as a tint, may be acceptable. However, when painting an already installed roof, there is a risk of excess paint seeping into the interlocks, hindering their performance and potentially causing water ingress.
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