Just look at the state of this large metal roof at Twin Waters before Jetts Pressure Wash turned up and rescued it. Using the Jetts surface cleaner, all the grime just washed away, and now it looks like new again. Corrugated iron metal roofs like this require periodic cleaning to extend the lifetime of the roof. Grime like this will cause rust and other damage over time if not cleaned. Pressure washing with pure water is safe and environmentally friendly, no chemicals are needed.