How to Paint Corrugated Metal Roofing

What You'll Need
Wire brush
Power washer
Primer
Paint
Bleach
Water
Paintbrush or roller
Ladder
Safety gear

A corrugated metal roof is an excellent, hard-wearing choice for many DIY projects, such as building outhouses and sheds. This roofing material has a typical lifespan of 40-70 years if taken care of properly. To maintain the roof’s integrity and condition, you must protect the metal with a layer of paint. With the correct paint and application technique, you can paint it once for up to 10 years of protection. Get started painting your corrugated metal roof below.

Step 1 - Clean the Roof

The first trick to corrugated metal roof is to not paint a dirty metal roof. Before applying a new coat of paint, you need to get rid of any oil, debris, and dirt buildup that already exists. Use a power washer or brush with a mild cleaner to remove grime and debris.

Step 2 - Maintain the Roof

dormer on a metal roof

Keep in mind that if your metal roof is located underneath trees, dirt and debris will accumulate on your roof more quickly. In the summer a galvanized roof will attract and fry many flying insects as well. Therefore, you should periodically clean the roof after you paint it so that it stays in good condition.

Step 3 - Use a Power Washer

Warning: When working with bleach, wear the appropriate safety gear, such as a breathing mask and safety gloves. In addition, exercise caution when using a ladder to get to the roof. Always have a friend hold the bottom of the ladder for extra security.

Use a ladder to get to the roof, and then use a power washer to clean it free from any flakes of rust or mold. For stubborn rust patches, use a wire brush. Then, use a solution of chlorinated bleach and warm water to clean away any mold or mildew. Let the roof dry completely before moving on to the next step.

Step 4 - Purchase a Primer

Next, find a galvanized-metal primer to prepare the surface for painting. These primers are usually solvent-based, though some acrylic-based varieties are available. Speak to the staff at a local specialized paint shop for advice.

Step 5 - Apply the Primer

Once you have the primer, apply it according to the manufacturer’s instructions. Allow it to dry completely before applying any paint.

Step 6 - Purchase a Paint

green metal roof

The type of paint you should use for the topcoat on your metal roof will depend on the weather conditions and roof position. A roof that will be often exposed to direct sunlight will perform best with a different paint composition than one in a damp, shaded area. To make the optimum choice for your roof, consult a paint specialist.

Step 7 - Apply the Paint

Before applying paint, read the manufacturer’s instructions thoroughly to check the recommended thickness of each paint coating. In addition, assess the weather. Don’t start painting the roof if it’s expected to rain in your area within 24 hours, or if temperatures will be dipping below 40 F during any stage of the painting or drying process.

Paint each coat evenly, making sure to get into all crevices. Generally, you should apply two coats of paint to a metal roof to achieve the right color. Allow the paint to dry completely between coats.