By convention, to clean a roof you apply a treatment solution. There are a number of them available but we stand by ours and we insist it's the best available to market.
Once the roof has been treated, the lichen/moss/algae will die and then rain will take it all away. And that's why right now is a fantastic time to get the roof under control. A roof treated now will be clean for summer.
Most places around the world get lichen of one sort or another but the gardens of lichen we see in New Zealand are really something special. We have clean air (which lichen likes) and our farmers tend to top dress with phosphorus (which lichen loves) so we tend to see the most active lichen gardens in rural areas and urban areas bordering the country.
So if you want a clean roof, call us here at Green Agenda and find out how we can help.