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  • Is Moss Damaging Your Roof?

    If moss is growing on your roof it's advised to have this inspected and removed by a professional. Leaving moss to grow or attempting to remove it yourself can cause additional damage. If you damage the tiles this can lead to higher repair bills.

    Moss is never good news for roofs. As the moss thickens and grows it can raise the shingles up and allow water to penetrate inside. This can lead to internal damp issues like rot and leaks.

    Moss build-up often causes more debris to get trapped on the roof. This promotes water build up and increases the risk of rotting and leaking. The moss itself can also damage roofing materials causing them to break down faster.

    Why Does Moss Grow on My Roof?

    There are many different species of moss, all of which grow well in moist cool areas. Moss does not have flowers, seeds or any root system to secure water, so they must have a damp environment to grow. All of these conditions can be found on your roof, depending on which direction it faces. In the norther hemisphere, moss typically grows on the north facing side. This is because the sun faces south for most of the day.

    Perfect conditions for moss growth include a shady climate, acidic environments, hard surfaces and moisture/humidity. Which is why, in the UK, the moss grows on the northern facing side of a house. Something to think about when buying a property and why people prefer a south facing garden in.

    How Can I Remove Moss?

    There are three main methods to get rid of moss:

    1. Remove the shade that the moss is growing in
    2. Make the environment extremely acidic or base
    3. Remove the moisture or water.

    Eliminating shade can be difficult on roofs, as it naturally has a shaded environment. You can of course remove trees to allow extra sunlight, but this can be expensive and if the trees are in a neighbouring property simply not possible.

    Where the shade is caused by permanent features such as surrounding buildings then removing the shade is simply not an option.

    When the shade cannot be removed, the best option is usually to use a roof cleaner spray on moss or algae growing on roofs. This is a step best left to the professionals that are used to working at heights and know how to deal with the chemicals.

    The better option is to remove shading by removing trees or bushes and trimming branches and anything else that may be blocking the sun, this is the better option.

    Homemade Moss Killer

    If you your only option is to remove the moss yourself, you can try using acidic household products is a cheap option for removing moss. Using vinegar, orange juice, lemon juice and tomato Juice are all highly effective at killing moss.

    It's advised to diluted them with a mixture of water still, as you want to kill the plant without the acid eroding any surfaces.

    Making the environment a base (above pH 7) will also effectively kill the moss. Common household items such as baking soda, baking powder, salt, ammonia, soap and bleach can all raise the pH high enough to kill moss.

    We always advise to use professional tradespeople to carry out this work for you and should not be something you try yourself.

    Removing Moss with a Pressure Washer

    It can be tempting to grab your pressure washer to remove the moss from your roof but be very careful using a hose to remove moss. Using a high-pressure washing can cause more damage to the roof than if you left the moss in place.

    If you to use a hose, use it on a low pressure and spray the water downwards (not up through the roof tiles/shingles) and gently scrub moss away.

    Do not scrape with a hard tool as this can rip, crack and break many roofing materials. It's surprising how fragile tiles can be.

    Also be careful with using acids and ensure your acidic mixture is not too strong or it can eat away at the roof itself. If using a home-made cleaning solution made from household materials, then try and test it beforehand.

    You can test on some spare shingles if possible before applying it to your roof. If this is not possible, use a weak solution and avoid leaving on roof for too long before washing off.

    You can also find products at your local DIY store for effectively removing all types of mosses from your roof. Remember to take great care when working at height. If you do not have the correct safety equipment then please hire a professional.

    Do you need to remove moss or weeds from your lawn? Lawn weeds and how to remove them.

    Tackle the problem early, or you might need to replace your roof sooner than expected.

    Last updated by MyJobQuote on 14th May 2016.

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