Is roof cleaning safe?:


A roof repair can be one of the largest repair bills you will ever have to consider when maintaining your property. Regular maintenance of your roof can prevent long term problems that would eventually cost you much more money.

Maintenance such as replacing tiles, replacing mortar, chimney pointing and guttering are common roof repairs. But increasingly roof cleaning is becoming an important consideration when maintaining a roof. Roof cleaning can prevent risks such as unseen broken tiles as moss can hide cracks, we have seen tiles where the moss has been there for so long that is has deteriorated the concrete tile and made a hole. The moss can lift up tiles and allow water ingress, it can block guttering and allow water to overflow and cause damp to penetrate the walls. Leaving moss on your roof can be unsafe, so the question is roof cleaning safe is frequently asked. If you can weigh up the pros and cons then you can make an educated decision. Allow us to help.


safe roof cleaning

Roof Cleaning Methods:


There are quite a few methods to cleaning a roof. We’ll qualify this first by stating that all methods are safe if done correctly by assessing and managing all risks. The important deciding factor should be choosing the professional company to clean your roof. We’ll list the methods from the worst to best. 


Pressure washing (Least Safe) – This is a great way to quickly clean your tiles, but if done incorrectly it is also a quick way to find all the leaking areas of your roof and to cause further damage. Pressure washing a roof has a bad reputation, mainly from cowboys in the summer trying to make a quick paycheck and not assessing the roof and pressure washing the tiles from below. This is a quick way to force water under the tiles into your attic space. When we pressure wash a roof we ensure that we have assessed that the tiles are in good condition, it is important to check that the roof has a underlay of felt and we ensure that any repairs necessary are done by us to the customers satisfaction.

is roof cleaning safe

Steam Cleaning – Steam cleaning will provide you with a great result, the roof will be cleaned extremely well. Although the pressure on the roof is low and the damage potential is not as much as high pressure washing with cold water. It still creates a mess and is not very cost effective, it takes just as long as pressure washing with the same requirements of accessing all areas on the roof with long trailing heavy hoses. The clean up is time consuming as the moss is heavy with water. The roof then need to be treated with a biocide to prevent the rapid regrowth of moss. All of these time consuming parts to steam cleaning a roof increase the costs of the job, plus the very expensive steam cleaning machinery the method is not very cost effective.

safe roof cleaning

Softwashing (Most Safe) – Soft washing is the term used to describe an umbrella of techniques using a variation of chemicals and surface preparation. For roof cleaning the tiles are usually scrapped clear of moss, this removes 90% of the moss with a simple scraper. There are tool that we use specifically for roof cleaning that make this easier and quicker, the whole process is less aggressive and damaging to the roof tiles. Softwash can also be done to a roof without removing the moss first, the chemical can just be applied to the tiles as is and left to fall to the ground and into the gutters. This must all be cleaned at a later date. We don not recommend this method unless it’s a DIY job or under an extreme budget. The usual professional approach to roof cleaning is done from roof ladders and scaffold towers. Unlike pressure washing there is less need to access every part of the roof by foot. Most scraping can be done from a few fixed positions using the extendible scrapers, this reduces the risk of damage caused to the tiles by foot traffic and moving ladders on the roof. The chemicals used depend on the company and the requirement, bleach is a very common and effective chemical. Other chemicals used are biocides, these can be known as DDAC and BAC50, these are the active ingredients found in household named products such as wet and forget. The strength we use is much higher and only recommended for use by professionals. As with any chemical, risks have to be managed all the chemicals used have the potential to cause damage to aquatic life. This risk is minimal and classed as LOW on any risk assessment when managed correctly.

roof cleaning safely

Cleaning Crew Safety:

We make sure our staff are safe when working at heights. Working with a pressure washer or steam cleaner on a roof is difficult. The washer hose is difficult to control. This can be done safer with an extendible lance or using a cherry picker to gain better access to the tiles.

 When scraping moss from a roof our crew wear fall arrest harnesses that can be attached to an anchor point. Safety is very important for our company. Our cleaning crews are very capable at working from heights

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safe roof cleaning

Safe Professional Roof Cleaning:

The professional way to softwash a roof is as follows. Every professional roof cleaning company should have a system that they follow to achieve the best results in a safe, time and cost effective manner. The roof should be assessed for any preexisting damage to tiles and pointing. This is sometimes difficult to identify until much of the moss has been removed as moss can hide many flaws, but once identified it should either be a quick fix or repair options discussed with the home owner. The down pipes of the gutters should be blocked to prevent blockages when the moss is being scraped from the tiles. Tarps are laid on the ground level, especially where there is gravel, grass, flower beds. This is to collect the falling moss. If it falls onto hard standing then this is easily cleaned.