How To Clean A Metal Roof On A House. Spray your roof down with wet & forget. Basically you put on various cleaning products via a garden hose sprayer, scrub lightly with a soft brush (presumably on a long pole) if needed, then rinse off with an excess of water.
And the runoff harms plants. This is to avoid damage to the roof and your body. Homeowners need only a water hose with enough pressure to reach all areas of the roof properly and a method of dispersing detergent and soap to the roof, usually by attaching a soap receptacle on the water hose line.
Wet & forget works with the rain and wind to get it clean.
Washing a roof is actually a fairly simple process. It is recommended that cleaning either of these be accomplished with a mild solution of detergent. Even at low pressure, a power washer can seriously damage shingles. Just like any other roofing material, however, it does require some level of maintenance to keep it in optimal condition.