Why should I remove moss on a roof and how?

13 Roof Moss 1 600X600

Is moss on my roof a problem?

Moss thrives in damp areas, particularly in shade, where the roof stays wetter for longer. Before long it will spread rapidly and can cause degradation to the roof. Plants will penetrate the surface and retain moisture against the roof surface which can expand and contract in freezing conditions, speed up wear and tear, dislodge tiles or take over certain roofing materials such as felt completely. Growth can block effective rainwater drainage and can be areason for insurance companies to refuse a claim. Rainwater captured like a sponge by moss which then leaks through the roof can cause mould growth on interior surfaces. Moss is also attractive to birds which may knock it off so that it blocks guttering.

Are copper strips any good at preventing moss on roofs?

Copper ridge stripping is known as a potential weapon against moss on roofs. There have been reports that bacteria in drinking water stored in copper vessels are destroyed by the leaching of copper into the water. Effectively, the same thing happens; when rainwater comes into contact with copper, its oxidisation releases a residue of copper oxide. The unstable copper and and oxygen atoms disrupt the cell walls of organisms such as moss. It inhibits moss growth as it is washed down by the rain. However, this can lead to green staining which can be very unattractive on anything in which it comes into contact, eg the roof, uPVC windows and clothing. There is further danger if this comes into contact with other metals, such as aluminium in guttering or windows, iron in cast iron guttering or steel fixings and even certain plants which could all be destroyed by the accelerated corrosion or electrochemical process. In addition, this method is only temporary, is only effective when it rains and in patchy areas where the rain can saturate the roof and moss.

Could I rake or pressure wash my roof to remove the moss?

When using any manual action, such as hard brushes, rakes or pressure sprayers, great care must be taken not to damage the roof, particularly if the condition of shingles, slate tiles etc are brittle, dislodged or crumbly. Often, harsh mechanical action can cause further damage to the roof. Light manual action to remove heavy growth is fine before applying our concentrated moss and algae killer Baticlean CR.

Is it expensive to kill moss on the roof or should I pay a contractor?

SPCB manufactures and supplies our solutions to both contractors and individuals. Some prefer to pay a roofing or cleaning contractor to clean the roof for ease, as such companies may have the necessary materials, such as sprayers and scaffolding and the experience. However, it is inexpensive to do the same work yourself. You will need a brush for removing any heavy moss, a sprayer for spraying the moss killing solution, perhaps with a long reach lance (such as our 5.4 metre telescopic sprayer lance), perhaps a guard to protect guttering from dead moss fall and the moss killer itself. The equipment can be used again, either for maintaining the roof or for other garden tasks. As Baticlean CR is concentrated, it covers a large area so for a 125 square metre roof, you will only need 5 litres at £29.75 (plus VAT and delivery).

Will Baticlean CR remove black spot, staining and lichen?

Baticlean CR is a systemic moss, algae and lichen killer and is designed to attack and penetrate the organism cell walls, effectively killing it from within. Whilst the growth is dead, it will remain on the surface. Dead moss can be brushed away or nature can take its course, if gutters are protected to prevent blockages. However flat growth and staining such as black spot and lichen may need further work. For this reason, we recommend applying Batifort first and using some mechanical action before rinsing away, then applying Baticlean CR as a surface biocide to kill remaining spores and prevent regrowth.