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Concrete Roof Tile Cleaning – Methods, Risks & Processes

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The topic of how to clean concrete roof tiles has been, and still is a very subjective matter. With the roof of your home at risk of damage you will wish to make an informed buying decision and ensure the safest roof cleaning process is used for your roof tiles.

Marley – one of the leading concrete tile manufacturers in the UK states

“The use of high powered jet washes is not recommended as it can damage the surface of the slate or tile, thus reducing its expected life considerably.”

And directs you to read the “Care, Maintenance & Repair of Clay and Concrete Roof Tiles” by the Roof Tile Association for further Guidance.

In the mentioned document it is stated that scraping can damage concrete roof tiles.

So even the UK’s leading concrete tile manufacturer and Roof Tile Association can not agree on the best method to remove moss and clean concrete roof tiles!

Concrete Roof Tile Cleaning Methods

Cold Water Jet Washing

Normally carried out by sole traders at the cheapest end of the pricing spectrum.

Not a service offered by The Roof Moss Cleaners Ltd.

Hot Water Pressure Washing

concrete tiled Roof after steam cleaning

Offered by many professional exterior cleaning companies, including us here at The Roof Moss Cleaners Ltd. 

Manual Roof Scraping & Biocide Treatment

Offered by many professional exterior cleaning companies, including us here at The Roof Moss Cleaners Ltd.

Risks of Each Roof Cleaning Method

Cold Water Jet Washing

Cold water jet washing uses high pressure water to remove moss, dirt and algae from your concrete roof tiles, but in doing so the high pressure damages the surface tiles reducing the lifespan by years – just as Marley, the UK’s leading concrete roof tile supplier states.

A cold water pressure washer that is powerful enough to remove stubborn moss & years of organic dirt from a concrete roof will be using around 15 liters of water per minute, at around 150 bar – with that comes the obvious risk of water ingress into your property, damage to concrete roof valleys and the pointing on your ridge and hip tiles.

Hot Water Pressure Washing / Steam Cleaning

concrete tiled Roof after steam cleaning

Hot water pressure washing, often referred to as steam cleaning because the boilers used with the pressure washer are capable of producing steam.

To achieve steam from the pressure washer and boiler the water flow and pressure are greatly reduced to around 60-70 bar, at the rate of around 8 liters per minute, which then allows the water to pass through the boiler slowly enough to reach temperatures of up to 150 degrees!

Steam cleaning is actually the method used to clean brick and stone on listed, historic buildings however it still comes with risks when used for roof cleaning.

The risks of water ingress are lower than cold water jet washing because the water is applied at a much lower pressure and volume. The risk of damaging the surface of the tile is also greatly reduced when using steam compared with cold water jet washing.

Manual Roof Scraping & Biocide Treatment

Manual roof scraping negates the risk of water ingress as your roof is cleaned without the use of a pressure washer.

There is a slight risk that tiles with hairline cracks in them could crack if they are caught by the scraper head at the wrong angle.

If too much pressure is applied on the scraper head then it can cause the concrete tiles to become scratched as mentioned in the “Care, Maintenance & Repair of Clay and Concrete Roof Tiles” by the Roof Tile Association

Our Expert Opinion on Cleaning Moss From Concrete Tiled Rooftops

Having cleaned what must be close to 1000 rooftops we know what works, what does not and which method causes the least abrasion and overall risk to the concrete surface of your roof tiles.

In our opinion the best method is to have a manual scrape of the roof followed by the application of a market leading, HSE approved roof cleaning biocide wash.

This method is certainly the least abrasive and longest lasting way to clean a concrete roof tile.

Access is less of an issue when it comes to concrete tiles than when cleaning slate roofs or clay tiles and slates because concrete tiles are strong enough to support the weight of a man using a roof ladder – which can save on the hire costs of expensive MEWP (Mobile Elevating Work Platforms) aka Cherry Pickers.

Our team carry a complete range of access equipment on board including mobile access towers, ladders and specialist roof ladders. They are also IPAF trained and insured for the use of Cherry Pickers, so if your roof is of a complex size and shape then we would be able to safely access and clean it for you.

Call The Roof Moss Cleaner Ltd For Concrete Tile Roof Cleaning Services

Call us today on 01494 355645 for a market leading roof cleaning service that is second to none!

We take pride in the service we provide from the moment that we answer your call.

If you are considering having your roof cleaned then do not hesitate to contact Peter at The Roof Moss Cleaners Ltd on 01494 355645