Does jet washing damage roof tiles?

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Jet washing can seem like a really effective way to clean your outdoor surfaces, whether you've got grubby paving stones, brickwork, or roof tiles, jet washing appeals to many. It isn't, however, always a good option. High-powered jet washes and pressure washers can be detrimental to some surfaces, so it's important to do your research before you start using your pressure washer on surfaces like your roof tiles.

So, can you pressure wash your roof? Will pressure washing damage roof tiles? Here's what you need to know with tips from the Uniwash Team.

Are pressure washing and jet washing the same thing?

Pressure washing and jet washing are similar things, but usually, jet washing (sometimes called power washing) involves using hot water rather than cool water. It's important to know the difference because some surfaces will be better equipped to cope with one than the other.

Can you pressure wash roof tiles?

You might want to brighten up the roof tiles, or remove moss from their surface, or perhaps you're looking to prepare your roof for a new sealant or coating. Whatever your reason, cleaning the roof tiles of your property isn't an easy job. Most people assume that a pressure washer will make it simpler. But that is not the case.

Why can't you power wash roof tiles?

In reality, pressure washing roof tiles will not just remove moss and algae, but it can also cause irreparable damage. Roof tiles, particularly the concrete roof tiles most commonly used in the UK, have a textured surface to enhance their durability. When they are met with the force of a pressure washer, this coating can be stripped away. This then shortens the lifespan of the roof tiles, leading to them needing to be replaced much sooner than usual.

On top of that, the force of the water used when pressure washing can also cause the roof tiles to loosen. This then impacts the structural integrity of your roof, causing gaps between the roof tiles to form. This can allow water to damage the surfaces under the roof tiles. Eventually, this leads to leaks and flooding in the loft, causing damage to the property as a whole, and could even damage the structural integrity of the loft space.

As the tiles move, cracks can form, which can lead to the tiles falling from the roof, damaging whatever they land on and causing a health and safety risk. This then requires immediate attention, usually in the form of replacing the roof tiles -- which is not a cheap job!

Finally, walking around on your roof tiles in order to do the roof cleaning can be damaging. Roof tiles are not built to hold your weight, whether they are clay roof tiles, concrete roof tiles or anything else. By standing on your roof space to clean roof tiles, you are increasing the risk of the roof tiles cracking and breaking as you do your roof cleaning.

How should you get your roof clean?

So if you cannot jet wash your roof, how should you clean roof tiles? Well, the general consensus from tile manufacturers and roofing contractors alike is that the best alternate method to pressure washing roofs is soft washing.

Soft washing is the low pressure application of specialist cleaning products for moss removal, algae removal and dirt removal. It is suitable for most surfaces that should not be pressure washed, and is the technique chosen by most roofing contractors. It will not damage roof tiles, render or any other surface, and the specialised cleaning chemicals will work effectively to clean roof tiles.

How does soft washing work?

Soft wash chemicals are applied to the roof tiles at a low pressure by using extendable poles (like those often used by window cleaners) that spray the product onto the surface through a nozzle or a brush head. The poles allow cleaners to reach hard-to-reach spaces, and the chemicals used are specifically designed to clean roof tiles.

The chemicals are then left to sit on the roof tile, to work their magic. Once an adequate amount of time has passed, the chemicals are rinsed away with clean water. Once dry, an assessment is done to see whether there needs to be another round of soft washing done.

What are the benefits of soft washing roof tiles?

As well as preventing you from damaging your roof tile, and being recommended by many tile manufacturers, there are a few benefits of soft washing roof tile over pressure washing.

The biggest benefit of soft washing roof tile is that the chemicals used in soft washing are absorbed into the pores of the roof tile, and as a result, it can help to keep the tiles clean for longer. By using biocides and other chemicals that target algae spores, the chemicals maintain your roof's cleanliness, even weeks after the cleaning has been done. Jet washing, or power washing, will clean the exterior surface of the roof tile, but it will not do much more than that.

How to keep your roof tiles clean in between soft washing

To save you from having to soft wash your tiles on a regular basis, there are a few things that you can do. Such as:

Apply a sealant to your roof tiles

There are specially designed sealants that you can apply (or pay to have applied) to your roof tiles in order to protect them from things like grime, algae and lichens. This can keep your roof safe and protected from things that may otherwise need cleaning.

Apply an anti-fungal roof tile paint

Moss removal is great, but if you can prevent moss growth, its even better. Anti-fungal paint will do a great job at preventing all sorts of growth, keeping your tiles cleaner for much longer.