How To Paint Corrugated Metal Roofing

Corrugated metal roofing typically resists water damage, which makes it a popular choice for buildings like sheds and garages. Metal roofing lasts a long time with proper care, but you may wish to paint panels to match the rest of the structure or restore faded panels. It isn't hard to paint corrugated metal roofing provided you feel comfortable working from heights. Follow this guide to paint your corrugated metal roof.

Prepare to Paint the Roof

To paint the roof, you need the following:   

  • work gloves tarp or plastic
  • extension ladder
  • broom
  • bucket
  • dish soap
  • pressure washer 
  • brush with long handle
  • medium-grit sandpaper 
  • paint tray
  • small paint brush 
  • paint roller with extension and 3/4 inch to 1-inch nap
  • metal-based paint and primer

Plan to paint during a spell with no rain for around two days. Lay tarp or plastic on the ground around the roof. Position a ladder on sturdy ground, and tie a safety harness to the other side, or get someone to hold it for you, Sweep debris on the tarp or plastic. 

Clean the Roof 

Check the roof for rust spots.Tin and steel roofs are more prone to rust, and aluminum should not rust since it contains no iron oxide. If the roof isn't very dirty or rusty, mix a tablespoon of dish soap in a gallon of warm water. For rust spots, use trisodium phosphate instead. Try to find a backpack pressure washer, so your hands remain free.

Spray the roof with a pressure washer keeping the nozzle several inches from the roof, then scrub with the brush until the rust and dirt have been removed, then rinse. To remove stubborn rust spots, sand them with medium-grit sandpaper. Rinse the roof, and let it dry.

Paint and Prime the Roof

Paint the roof before fall to avoid leaves staining fresh paint. Paint the roof using galvanized exterior metal primer and paint. If you want to reduce the roof temperature, apply reflective paint, which deflects over 80% of the heat.

Attach a thick nap to your roller, pour some primer in the tray, and brush each panel working in long, even strokes until you cover the metal, and change roller naps as needed. Use a small paint brush to cover screws and between panel seams. If the primer drips, use a clean paint brush or rag to wipe them, and apply less primer.

Let the primer dry until it no longer feels sticky or according to directions. Brush the paint on the panels in the same way, and let it dry.