Roofs can become built up with moss and mould, which when left can damage the surface and lead to porous roof tiles. The high pressure water kills the moss and mould, and prevents it from coming back easily. Roof and tile cleaning mean that the surface will look nicer, but also helps with roof preservation, avoiding costly repairs and tile replacement. 500-700bar machine for rust, dirt removal. 2000-2800bar machine for paint removal.