How to Repaint a Metal Roof

roofer repainting a metal roof

Metal roofing is an eco-friendly and attractive alternative to traditional shingle products like asphalt. Metal roofs are durable and will last for a long time with minimal repair or maintenance. However, over time, these roofs will require repainting. Repainting a metal roof doesn’t take long. It can usually be done over the course of the weekend. Here, let’s show you a 5-point plan to make sure you do it correctly and safely.

Examine the Roof

Before you start, you need to make sure you determine the type of metal the roof is made of. It could be a galvanized metal or it might be known as terne metal, although the latter has been phased out due to the dangers of lead. If the roof is terne, it is best painted with oil-based paint. If the roof is made of galvanized steel, it cannot be painted with oil-based or aluminum-based paint, and requires either a zinc-dust type paint or latex paint.

Preparing the Surface

Scrape away any floating or loose paint using a putty knife. If you are struggling or encountering tough areas of paint, you can use some sandpaper or a wire brush. Make sure that you remove all the rust using the sandpaper or wire brush, sand the metal roof surface very lightly using the wire brush or sandpaper. You can use a pressure washer to do this, but hand-scraping is a better approach as you can see the roof with your own eyes so you can identify any problem areas that you may need to repair. The important thing is to achieve a textured finish. This is because it can help the new paint bond with the roof finish. 

Clean the Roof

Make a simple mixture of one cup of mild laundry detergent or dish detergent to 5 gallons of water. Using some rags, apply this mixture to the roof being sure to remove any debris, dust from the sandpaper, or grease. Spray the roof with a hose to rinse away any debris. 

Apply the Primer

After the roof has dried, coat the metal roof surface with a rust-inhibiting primer. Be sure that you choose the right product that states it can be used on outdoor metal. Apply this primer with a roller, follow it up with a paintbrush to access the harder to reach areas. Allow this primer to dry completely as per the instructions.

Paint the Roof Surface 

Use an acrylic latex paint. Refer to the instructions and make sure that it is designed for outdoor metal. Using a brush or a roller, apply the paint liberally. Wait for the paint to dry and if necessary, apply a second coat. Ideally, two layers of heavy coats with a roller will ensure you cover any mistakes, but when painting the roof, work from different directions. For example, if you paint from the back to the front, go from the opposite direction for the second go so you guarantee full coverage.

Leave Comments