The process of roof cleaning is a controversial subject. Some prefer to pressure clean a roof, some like to scrape the roof and some people like to just chemically treat a roof. There are benefits of each of these 3 methods.
Pressure cleaning your roof offers quick results with it looking new after the job is done but it can be unsafe if your contractor doesn't understand the type of tile, the age of the tile and if they haven't analysed the roof througherly first. It can cause leaks and if too much pressure is used it can damage the tiles.
Scraping the roof to remove all the moss and growth is a safer method but still needs to be done with care to not ruin your tiles. Some tiles require a steel scraper blade and some tiles are more delicate and require a nylon scraper blade otherwise it will scratch the roof and ruin the surface of the tile, leaving it looking terrible
Just using chemicals on a roof and not removing the existing moss is also a popular method but leaves the roof looking like a dead lawn. It takes months for all the moss to die off and fall off with the rain. Leaving a huge mess and a patchy roof.
Here at WNC Jet Services, we choose to scrape the roof (after we have taken the time to analyse the roof) to remove all the moss and growth that has grown over the years. We then sweep the roof to remove all the loose moss and grime. Once the roof is clean we then apply a chemical mix to kill off any remaining living organisms. The chemical we use is self-depleting so it is safe. It works by breaking the cell membranes and killing the cell of the living organisms.