Why should I have my roof cleaned?
Cleaning a roof can substantially extend its lifespan, and keep gutters clear of moss and other debris which, if left, can cause damp issues within your home.
Moss and algae can damage clay, concrete, and slate roof tiles over time; causing them to become porous which can make them fragile and vulnerable to cracking in poor weather.
Additionally, moss and other debris can accumulate gutters, causing them to block and overflow; creating more problems which may be visible from inside your home.
How do you clean a dirty roof?
There several ways to clean a roof; each has its own benefits and pitfalls. Here, we outline four of the most popular methods used.
Soft Washing
A gentle, low-pressure method of cleaning which uses a chemical solution to kill organic matter and detach it from the surface. It is widely considered to be a highly effective method of cleaning roofs.
The low-pressure application of soft wash chemicals reduces the chances of damage during cleaning or water ingress into the property. The soft washing process kills all organic matter and, provided it is undertaken by competent technicians, leaves treated areas spotless, sanitised and the results will last for a long time.
Soft Washing requires a lot of training along with highly specialised equipment and chemicals to produce long-lasting, high-quality results. Access to the areas to be soft washed can be problematic in confined spaces as the solutions need to be sprayed from a few feet away rather than in close proximity to the surface.
Care must be taken to prevent soft wash solutions from entering drains or falling onto landscaped areas or gardens without immediate counter treatment to prevent soft wash solutions entering drains or falling on to landscaped areas or gardens without immediate counter treatment.
Scraping
Scraping is a method of moss removal widely used to remove the most visible organic growth from a roof. In many cases, it can be undertaken from the ground with the aid of an extending pole system.
A metal blade shaped to suit the roof’s tiles attached to a pole is used to scrape moss and other debris from the surface. It is an effective method of removing heavy moss growth and – provided the gutters are cleared immediately after scraping – can reduce the likelihood of gutters overflowing in the future. The equipment required is minimal and inexpensive and can be undertaken with little experience or training.
Scraping a roof can give immediate visual results but these are often short-lived because the roots of the organic growth are not removed by this process. This can promote the regrowth of moss to a greater degree than before – similar to pruning a bush in the autumn to promote strong regrowth in the spring.
The process of scraping a roof can disturb tiles and pointing; particularly as it is often undertaken by unskilled individuals from quite a distance away, making it impossible to clearly see any issues or damage.
Pressure Washing
Pressure washing can be a highly effective method of cleaning all kinds of surfaces and many homeowners will already have their own pressure washer for car washing etc., making them familiar with the principle.
Water is projected under high pressure towards the surface in question to remove the dirt, moss, lichen, and other debris. Pressure washing can yield visually compelling results with little experience or expertise from the operator.
The use of high-pressure water to clean a roof carries the inherent risk of water ingress to the structure beneath. Water being forced ‘uphill’ on a roof will be forced beneath tiles and into the timber battens, felt, rafters and purlins. A greater risk associated with pressure washing is that the pressure is often so harsh that it can damage and crack roof tiles and remove vital mortar pointing.
Pressure washing can produce visually pleasing results but it is highly unlikely to remove all of the organic matter; causing faster and more prolific regrowth in a relatively short timeframe.
Steam Cleaning
• Steam Cleaning can be used in some circumstances to clean roofs but it is more widely used by cleaning specialists to clean stonework and certain types of cladding.
Specialist steam cleaning equipment, given the nature of steam, it can be dangerous in untrained hands or if equipment is poorly maintained.