Metal roofing materials provide a long lasting and durable solution to your roof, but like all roofing materials, weather exposure and general wear and tear can take a toll over time. Rust, corrosion, mold, and caked on dirt can mar the appearance of your roof and reduce the lifespan of your roofing materials, driving up long run maintenance and repair costs. Thankfully, a semi-regular cleaning of your metal roof can keep it in good condition well into the future.

What You'll Need

You'll be using a ladder, a wire brush, trisodium phosphate (TSP), a large bucket, a pressure washer, a soft bristled brush, exterior metal paint and primer, and a paintbrush to clean your metal roof. All of these items can be found at most hardware stores if you don't already own them at home. You may also want to have someone spotting you while you're on the ladder to help prevent a fall.

Cleaning Metal Roofing

First things first, you'll want to climb up the ladder and note all the places on your roof where rust and corrosion have taken hold.

Use the wire brush to gently scrape the rusted area. You'll want to remove all the visible rust and flaking paint, but take care to not use too much force to avoid scratching the finish of the metal roofing itself.

Repeat as needed over the entirety of your roof until all rust spots have been removed.

Next, make a mixture of a gallon of warm water with half of a cup of TSP. Make sure that the TSP is properly diluted, as a strong mixture can cause damage and bleaching to the paint on your metal roof.

Then, use the soft brush to apply the TSP mixture to any plant growth or mold which has taken hold on your metal roof. You'll know it's working when the mold begins to turn white.

Spray the roof down with the pressure washer to remove the dead moss and clear away any lingering TSP that may bleach your roof. You'll also want to clear away any dirt that may be caked onto your roof. Start at the peak of your roof and work your way down, as the water flowing down the slope of your roof will loosen any other spots of dirt.

Finally, let the roof air dry completely. Then, apply the metal primer to the spots that you scraped free of rust and flaking paint. You'll want to let the primer dry before applying the paint (and for good measure, you'll want to let that coat of paint dry as well before applying a second coat to prevent future rust damage). If you don't have the time or patience to do this on your own, you can contact a roofing services company like All Weather Exteriors to do it for you.