How to Kill Moss on Roofs Naturally Using Sodium Percarbonate may earn a tiny commission (at no extra cost to the user) if a purchase is made through clicking a link.This goes to help with the running of the site and I really appreciate the support.

Moss loves to grow on roof tiles and wooden shingles. The surface of roof tiles have 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 the damage of 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”.

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How Much does it Cost to Kill or Treat Moss on Roofs?

The simple answer is, it should not be too expensive. Professional roof moss killers can be expensive as can the roofers needed to apply the chemical. The use of professional roofers should not be underestimated. Climbing up ladders and on to delicate roof tiles at 25 feet up is best left to the professionals. This should be the main cost of killing moss on roofs.

The most effective roof moss killer is Sodium Percarbonate. It’s an easy to apply granule which, 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 which 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 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
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There are Many Benefits to Using Sodium Percarbonate as a Roof Moss Killer.

  • 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 the there is roof run off to these systems.
  • It prevents moss 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.
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How to Use Sodium Percarbonate as a Roof Moss Killer.

  1. Dampen the Area

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

  2. Spread the Granules

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

  3. 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 which will get washed down by the next rain shower.

  4. 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 it’s magic.

You can buy sodium percarbonate from or