How to Paint Metal Siding

corrugated metal siding
What You'll Need
Pressure washer
Paint sprayer
Safety gear
Oil-free liquid soap
Masking tape
Metal-paint or latex-bonding primer
Metal paint
Acrylic latex paint
Paint roller
Roller extension
Plastic sheeting
Paint tray
Trisodium phosphate
Rust converter

Over time, your metal siding will turn dull and rust. You can spend a long time trying to remove the rust again and again, or you can clean it once and paint over the metal to make it look new, protect it, and prevent as much rust from building up on the metal surface in the future. Follow this guide to learn how to properly paint siding made from steel and aluminum and give it a facelift.

Step 1 – Cleaning the Metal Siding

Metal siding is often subjected to extreme moisture that will make it rust or accumulate a thin layer of oil. So, before you can paint the siding, you have to properly prepare it.

Cleaning Aluminum

For aluminum siding, use a pressure washer set on “low” to spray the metal siding and rinse the rust off. Add liquid soap to the water to get the grime off. Then, rinse off the siding again with clean water. Allow it to dry for two or more days before continuing.

Cleaning Steel

Warning: Always wear protective gear when working with trisodium phosphate. TSP is a caustic substance that can burn your skin.

To clean steel siding, add trisodium phosphate, or TSP, to the paint sprayer and clean off any grime with it. If there is any rust on the steel, apply a rust converter over the siding, which will turn the rust into a black substance you can easily clean off.

Step 2 – Protecting Other Areas

Just like any other painting project, you will need to protect anything that is not being painted. Cut and trim plastic sheeting to fit over all your doors and windows that are in your painting path. Affix the plastic sheeting using masking tape.

Step 3 – Applying Primer

Decide whether you want to use a paint sprayer with a 5-gallon pail, or a paint roller with an extension. For steel, use a latex-bonding primer instead of a regular metal-paint primer. When ready, pour the primer into the paint container on the sprayer, or pour the primer into the paint tray. Then, apply the primer to the metal siding in even strokes. Start at the top of the wall and across the length of the metal siding.

Step 4 – Letting Dry and Cleaning Equipment

Let the primer dry for at least 1-2 days before applying the acrylic paint to the metal siding. While you wait, clean the paint sprayer according to the directions and clean out the brushes and paint tray. Allow your equipment to completely dry.

Step 5 – Applying Paint

Apply the acrylic paint to the wall on top of the primer in the same way you applied the primer to the metal siding. Wait for this layer of paint to dry, and then apply a second coat. Once dry, remove the plastic sheeting and masking tape.