How to Kill Moss on Roofs Naturally Using Sodium Percarbonate

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Moss loves to grow on roof tiles and wooden shingles. The surface of roof tiles has many cracks and crevices and this is a perfect place for moss spores to hide and grow. Moss loves a cold, damp and inhospitable environment so north facing roofs are usually the worst affected. There are many types of roof moss killer available, however, not all are easy to apply and can be hard on the wallet.

Will Moss Damage my Roof?

Moss soaks up water like a sponge. This can be a problem in the winter, when the temperatures plummet, the moss can freeze and when things freeze they generally expand. The constant moving of the moss covered saturated area can eventually lead to damage to your roof tiles or shingles.

Don’t worry! You don’t need to rush up a ladder with a sprayer filled with moss killer at the first sign of frost. The damage can take a long time to occur. Killing moss on roofs is more of a “damage limitation exercise”.

How much does it Cost to Kill Moss on Roofs?

The cost of treating moss on the roof of an average 3 bedroom semi-detached house could be as little as £160. This price includes £120 for the roofer for 4 hours and 10 kg of Sodium Percarbonate at £40. Prices will vary across the UK depending on the location.

Although professional roof moss killers can be expensive, as can the roofers needed to apply the chemical, killing moss on roofs doesn’t need to break the bank. That said, the use of professional roofers should not be underestimated. Climbing up ladders and onto delicate roof tiles at 25 feet up is best left to the professionals.

What is the most effective Roof Moss Killer?

The most effective roof moss killer is Sodium Percarbonate. It’s an easy to apply granule that, when mixed with water, produces oxygen. It’s this reaction that breaks down the small roots (rhizoids) which moss needs to feed. It also has the added benefit of killing off the spores that the moss releases in order to reproduce, therefore removing the chances of moss multiplying and populating your roof.

As a rough guide, 10kgs of Sodium Percarbonate will treat the roof of an average size house. It should take half to one day to apply depending on the ease of access for a professional roofer.

how to get rid of moss on roofs
Roof sprayed with Water and then sprinkled with Sodium Percarbonate

There are many benefits to using Sodium Percarbonate to Kill Moss.

  • Sodium percarbonate can be used in the rain or if rain is imminent.
  • Sodium percarbonate is eco friendly.
  • There is no damage to grass or plants.
  • There is no damage to septic tanks if there is roof runoff to these systems.
  • It prevents moss from regrowing on your roof. Sodium Percarbonate kills the spores that reproduce moss
  • Easy and quick to apply. No going up and down a ladder refilling spray tanks.
  • Direct application. No spray drift of nasty chemicals.


How to Use Sodium Percarbonate as a Roof Moss Killer.

Dampen the Area

Sodium Percarbonate is best applied in damp conditions. If it’s not raining use a hosepipe to damp down the tiles, this enables the granules to stick to the tiles and also starts the oxygen producing process.

Spread the Granules

Wearing gloves, spread the sodium percarbonate by hand over the whole roof. Roughly a Handful (50g) will cover 1sqm. 

Sodium Percarbonate Starts to Work

After about 15 minutes the roof will turn white as the water reacts with the sodium percarbonate. Sometimes there is a white residue left which is the by-product of the water and oxygen reaction. This is soda ash, an inert substance that will get washed down by the next rain shower.

What Happens Next?

Over the following days, the moss will turn brown and die. Over time it will slowly disintegrate. Sodium percarbonate is a powerful cleaner so your tiles will start to look cleaner as it works their magic.

You can buy sodium percarbonate from amazon.co.uk or eBay.co.uk

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