How To Clean a Painted Metal Roof

Having a beautiful, durable, painted metal roof can make your house really stand out among the rest. One of the best parts about metal roofing is that it is basically maintenance free. In most areas, normal rainfall is sufficient to keep the metal roof surface clean. When an unusual amount of dirt is appearing on your roof, a simple cleaning procedure should be scheduled periodically to keep your roof looking vibrant and beautiful. Excessive dirt usually occurs in areas where there is heavy construction, farming, or in situations where trees or other obstructions prevent the rainfall from reaching the roofing surface. Distinctive Metal Roofing is providing this guide on how to clean a painted metal roof so you can clean your roof yourself.

Removing Dirt and Grime

One of the most common problems you’ll run into is something that every roof type has to deal with. The accumulation of dirt, dust, and grime over time is inevitable, and it can affect the look of your roof. All you need to do to fix this problem is affix a soap receptacle to your hose line and spray a simple detergent over the entire roof. One thing to look out for is the amount of phosphate in the detergent. For surface dirt, the use of an ordinary non-abrasive household detergent is recommended After spraying the roof with the detergent, you can rinse it with water from the same hose.

When the dirt and grime is severe, use the following solution:

  • 1/3 cup ordinary non-abrasive household detergent (eg: Tide)
  • 2/3 cu trisodium phosphate (eg: Spic N Span)
  • 1 gallon of water

Caution: Stronger concentrations of cleaners can cause damage to the finish. Rinse the surface with clear water immediately after cleaning. Avoid skin contact or getting the solution in your eyes. Always wash the shingles from the bottom to top and keep rinsing thoroughly with fresh water while cleaning.

Removing Moss, Mildew or Algae

Depending on where your house is located, you may deal with problems such as moss, mildew, or algae growth. This situation can occur if you are you home is located in a heavily wooded lot where sun or rainfall has a very difficult time reaching your roof surface. In these situations, prepare the following solution.

  • 1/3 cup powder detergent (eg: Tide)
  • 2/3 cu trisodium phosphate (eg: Spic N Span)
  • 1 quart 5% sodium hypochlorite (eg: Clorox)
  • 3 quarts of water

Caution: Greater amounts of concentration may cause damage to the finish. Always test any cleaner on an inconspicuous area before applying to major areas. Excessive rubbing will create an undesirable glossy finish.


No matter which cleaning process you use, always keep in mind that you must rinse the roof afterward. Go over the whole area again with a water and soap mixture. Follow this by hosing the entire area down with water to ensure you have thoroughly rinsed away all debris. Leaving chemicals on your roof is a very fast track to even more problems, so it’s best to be as thorough as you can.

Distinctive Metal Roofing hopes that this guide on how to clean a painted metal roof has shown you how simple and important the process is to the look and longevity of your roofing. When it comes to metal roofing contractors in Pittsburgh, PA, Distinctive Metal Roofing is your go-to choice for the best help available.

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