Our first suggestion is a Roof treatment. This involves LOW pressure (almost no pressure) chemical spray on the roof. Once applied this will instantly kill all the lichen & moss growing. It will work itself off over a period of 6 – 9 Months. Run, sun, rain, sun….. this will work all of the organic growth off.
Although this is a LONG time and provides slow results, we recommend this in most cases as 70% of roofs are not water tight. If we HIGH pressure a roof- we risk the chance of a leak.