Green signifies a number of things. In the fairytale/fantasy world, it would represent a cottage deep within a tranquil forest, far away from evil’s clutches. In real life, and with the exception of green painted tiles, there is no other reason for a green roof except wide spread growth of the plant that is moss.
If you have been a victim of this situation before, you probably know how hard it is to fight and prevent, even with dedication and a host of sophisticated cleaning materials. Once that green moss blanket forms and covers a section of your roof, you know that your house is in trouble. It’s effects when in full bloom are very destructive to any house roof and later lead to leaking and seeping of water through the roof on rainy days. In no time, the roof gets damaged and has to be replaced.
How does moss grow on roofs
Moss appears as a green soft plant with a velvety sheen to it. It easily grows on roofs courtesy of its short roots that do not need to penetrate deep. As a plant, it grows well in humid/wet areas with a lot of shade and an optimum pH range of 5.0 to 5.5. It can grow on by roof type i.e. metal, clay, asphalt or wood; usually first appearing in the spaces between shingles before spreading out.
How to remove moss from your roof
It is advisable to start removing moss from your roof the moment you detect its growth. Once it grows too deep into your shingles, disaster becomes inevitable. Ideally, a cool day is suggested for any moss-killing activities.
1. Kill it first
Moss on the roof is like a weed in a garden, and so needs to be destroyed before trying to clean it away. There are a number of options available to you for this particular activity.
- Start by doing away with any form of shade over the roof. It can be from big tree branches or another building, and happens to be a major supporting factor for moss proliferation. If the source is neighbouring trees, do away with the branches covering the roof and expose the moss to sunlight.
- Fix a zinc or copper strip at the top/ridge of the roof. Whenever it rains, some copper or zinc molecules dissolve in rain water as it hits the ridge. These molecules create an alkaline environment that is unfavourable for moss growth.
- You can also apply chemicals such as zinc chloride and zinc sulphate. These are sold in granular and powder form and have to be mixed in water before applying on the roof. Chlorine solution is effective, but it is highly toxic and has effects on the roof ranging from discolouration of tiles to material disintegration.
- This might not be the easiest method of killing moss, but a mixture of hot water and salt can go a long way in starting you on the cleaning process. Mix a good amount of sea salt in hot water and use a hose pipe to spray it all over the roof for better results.
- You can apply commercial chemical solutions such as the ones sold in supermarkets that are designed to specifically kill moss, algae and mildew. Research about a product’s effectiveness before buying it. Common names include Wet &Forget, Zinc B Ware etc.
- Make use of home-made chemical solutions, too: vinegar and lemon juice are good choices for turning moss growth areas more acidic while baking soda, ammonia, soap and baking powder are proven choices for making the growth area alkaline. Both alkaline and slightly more acidic conditions inhibit moss growth and kill it as time goes by. You can add these solutions to water and then spray them on the roof with a hose. (Beware of creating very acidic solutions; they tend to eat away at the roof shingles.)
2. Clean the moss away
Next, you have to clean the moss from the roof surface it’s growing on. Thanks in part to its shallow root growth, scrubbing moss is relatively easy since it doesn’t grow to a great depth or grow firm like plants on soil surfaces.
- To scrub, you will need good cleaning agents, water and a long scrubbing brush. Apply the cleaning agents and water early enough to loosen the moss before scrubbing. Remember to wear shoes with well ridged soles to increase friction while scrubbing. The roof will get slippery during cleaning, potentially leading to some dangerous accidents.
- You can apply oxygen bleach on the roof. You can create oxygen bleach by mixing its powder in water and spraying it on the roof. The chemical uses its oxygen ions to break apart molecules and doesn’t discolour roofs or lead to disintegration.
- Another method, is water blasting. It involves squirting water onto the roof from a hose at high pressure but it can damage the roof if care is not taken.
Cleaning away moss, though not an easy task, is required the moment you detect it on your roof. With the few guidelines above, it shouldn’t be so hard.
Happy moss cleaning!