Roof Tiles are at the mercy of all the elements so it’s not surprising that as time goes by, they start to show their age. A build-up of organic material like algae, mould and lichen combined with the effects of traffic pollution and weather damage can leave you with dirty, stained and unsightly roof tiles.
How to clean roof tiles is a problem that is not easily solved. Working on a roof involves significant difficulty and danger so before you think about cleaning your own roof tiles, consider whether you have the necessary equipment, skills, physical strength and mobility necessary for this job.
Safety warning
You’ll need non-slip footwear as roof tiles can be very slippery. You’ll also need a sturdy, safe ladder which will reach your roof and if your roof is in bad shape, you may need to put up scaffolding and guardrails so that you can safely clean it.
You should never work alone on your roof, so you should also make sure that you have a friend or colleague who can partner up with you on this task. Your partner can help you by passing things up and down the ladder and he or she will also be able to see the roof from another perspective and let you know which areas you need to focus on.
Most importantly, working with a partner means that there is somebody there to help you if things go wrong and to alert you of any safety hazards which you might not be able to see.
If you have any doubts about your ability to work on your roof, consider spending a few pounds and hiring a professional to do the job. It’s never worth risking your health or your life for a DIY or cleaning task. However, if you’re sure you are up to it, here are some handy tips for cleaning roof tiles
back to menu ↑Accessing your tiled roof
To get to your roof, you’ll need a strong and sturdy ladder. Place it against the roof in an area close to where you will be working. As you are ascending and descending the ladder, get your partner to hold the ladder for you to keep it steady. You may be able to work on the lower tiles while standing on the ladder. Always make sure that your partner is holding the ladder steady while you do this.
Walking on a tiled roof
Roofs have a tendency to be slippery, particularly if there is algae, moss or lichen on there so exercise extreme caution while walking on the roof. If you will be using a pressure hose, the roof will become more slippery as you progress. Always try to walk on the driest parts and stick to the places where tiles overlap as these are the sturdiest places on your roof.
If you need to walk directly on the tiles, try to keep on the lower part of the tile as this has more support than the upper part.
If your roof is slippery or if you have any doubts about how safe your tiles are to walk on, you should erect guardrails before starting your job. You can rent roof guardrails from a number of suppliers around the UK.
back to menu ↑Treating your roof tiles for algae, moss and other organic growth
Organic matter can be very unsightly, giving your tiles a dirty green appearance but luckily this is very easy to treat. Mistral’s Lancelot Green Cleaner removes algae, mould and fungus from roof tiles, driveways and other surfaces. It also prevents regrowth for several months. The product comes in a 5L container and can be diluted to give you up to 50L of cleaner.
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However, for roof use, the manufacturer recommends diluting it 1:4 with water so you’ll get 20L which is still plenty for the average roof. You can apply this with a pressure sprayer by filling up the tank with the diluted solution and using a low pressure setting on to distribute the cleaner over your tiles.
You can use any pressure sprayer for this job but I really recommend using a Back Pack sprayer like Spear & Jackson’s 15L Back Pack Style Pump Action Pressure Sprayer which will hold enough cleaning solution to do your whole roof. Using a backpack water tank means that your hands are free if you do slip or trip on the roof and it does make for easier application. However, do note that when full, the tank weighs 33 lbs so if this seems too heavy for you, you can use a smaller tank and pass it up and down the ladder for refilling when you need to do so.
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To distribute the Green Cleaner on your roof safely, start at the furthest point of your roof and work back towards your ladder. This will save you from having to walk on the wet part of the roof. The Green Cleaner is not caustic and doesn’t contain any harmful chemicals.
The good news is that you don’t have to rinse this product off. You leave it on and let it do its work gradually. It will take several weeks for you to see results.
The bad news is that this will only work on organic matter. If your roof tiles are dirty and discoloured from environmental pollution like soot, traffic fumes or other pollutants, Green Cleaner won’t do much.
back to menu ↑Removing Dirt and Non-Organic Matter from Your Roof
While moss and algae are relatively easy to remove, if your roof has been stained and discoloured by smoke, traffic fumes and other non-organic matter, it can be a little trickier to clean your roof tiles.
Cleaning products like the Green Cleaner are not suitable for this kind of job and you will need to apply a heavy duty cleaner and then use an electric pressure washer to rinse off your roof. Kärcher’s Universal Pressure Washer Detergent can be used for all kinds of cleaning tasks and is ideal for your roof tiles. The product cuts through oil, soot and pollution staining so it is perfect for city rooftops.
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There are two ways you can apply the product to your roof.
- If your pressure washer has a detergent canister, then fill it up with the cleaner. It’s a little difficult to pour directly from the detergent container so a funnel will help if you have one.
- If your pressure washer doesn’t have a detergent chamber, then you’ll need to apply the cleaner by using a pressure sprayer like the Spear & Jackson backpack model above or you can their smaller 5l model which comes with a handy shoulder strap.
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Using the lowest setting on your pressure washer or pressure sprayer, apply a layer of cleaner all over your roof tiles. Always work from the furthest point on your roof backwards towards your ladder so that you don’t have to walk on the wettest part of the roof. Leave the detergent to soak in for about half an hour before rinsing it off.
Be extremely cautious when getting back on your roof as the surface is now likely to be very slippery.
To rinse off the product, use the lowest setting on your pressure washer as high power could damage your tiles. Once again, work backwards from the furthest point, being sure to thoroughly remove all the detergent.
Once your roof has dried, you should notice a significant improvement in how it looks.
back to menu ↑Cleaning Roof Gutters
If you are cleaning your roof, it’s a good idea to clear out your gutters as well. Gutters routinely accumulate all kinds of leaf debris and other mystery items. I’ve found dog toys, kid’s toys, packed lunches and all kinds of strange things in mine over the years. You should always clean gutters while standing on a ladder, never while standing on the roof.
Start off close to a down-pipe and first remove any twigs, large clumps of leaves or any other bulky material from the gutters. You’ll definitely want to wear protective gloves while doing this. Use a bucket for the debris. Once the larger materials have been cleared, flush out the rest with a hosepipe.
If, after this step, you find that the gutter isn’t draining, you may have a blockage in your downspout. If you have a power nozzle for your hose, attach it and direct water up the hosepipe. If you have a pressure washer with an angled spray lance, you can insert this in the pipe and use it to clear the blockage. This should clear anything that is obstructing the pipe.
Occasionally you might find that even after learning the downpipes, there is still standing water in your gutter. This is a sign that your guttering is not angled correctly. Your gutter should slope slightly downward towards the down-pipe at a decline of about 1/4 of an inch every 10 feet.
Ideally, you should clean your gutters at least twice a year to keep them draining properly and prolong their lifespan.
Hopefully, this article has given you some good advice about how to clean roof tiles. Please do be extra careful when working on your roof. Never take risks or cut corners when it comes to your safety. Remember, roof tiles and gutters are replaceable, but you are not!
