Can You Paint Metal Siding? 8 Tips for a Prime Paint Job

While metal siding has plenty of perks, it's also prone to fading, chalking, and accumulating a rather unpleasant sheen of green and gray mildew. The question is: Can you paint metal siding? In short, yes. Painting metal siding is one way to refresh your home's siding, but the type of paint, method, and cost to paint your home's exterior will vary depending on a few factors. 

1. Get to Know Your Siding

To start things off, get to know which type of metal siding is on your home and when it was installed. Nearly all metal siding materials—including aluminum, steel, and tin—receive paint with some preparation, but copper requires a particularly special approach. 

If your metal siding is relatively new, such as under two years old, there's a chance it still has its original pre-finish coat. An existing layer of finish requires significant stripping or sanding before you can paint metal siding. Keep in mind that paint needs friction to adhere to a surface. 

Keep in mind that painting metal siding costs between $1.50 and $2.50 per square foot, or an average of $400 to $3,500, depending on the size of your home. These numbers include the prep, primer, and actual paint necessary for the job.

2. Prep and Protect Your Home

Before you begin cleaning, sanding, or priming, take the necessary steps to prepare your home exterior for painting. If your metal siding has a current coat of paint—and you suspect it's been there since the 1970s—it's smart to hire a metal siding installation pro near you to test it for lead.

Next, lay down tarps to protect the plants and area of lawn directly surrounding your home. Cover windows with clear plastic and secure with painter's tape to lower the chance of leaks. Additionally, consider covering your lighting fixtures and always turn off the power to exterior appliances before exposing them to water or chemicals.

3. Clean Your Siding Carefully

Cleaning is the first key step to painting metal siding the right way. Most metal siding can handle a power washer, but always keep the PSI below 1500 to be safe and avoid damage.

You'll likely encounter three main types of grime on your metal siding: dirt, salting, and mildew. While the first is self-explanatory, salt forms on the side of metal homes close to the ocean. The salt accumulation can not only wipe off on your clothing, but it can lead to siding corrosion. Mildew forms on metal siding in particularly humid and high-precipitation areas. Opt for a gentle cleaning solution no matter what's on the side of your home. Detergent, dish soap, or other gentle exterior cleaners are best.

4. Strip or Sand, If Necessary

Metal siding requires the same pre-painting career as a piece of old wooden furniture. If your siding still has a finish from the manufacturer, you'll need to strip it off with a chemical paint stripper or by hand with a sander. Unsurprisingly, this process can take some time, so you may want to hire a professional painter for the job.

5. Choose the Perfect Primer

Take a close look at the specifications on your prospective can of primer. While some paint primers are best for aluminum, others bind best with steel. In either case, it should note its compatibility on the label. In most cases, the best primer for exterior metal siding features acrylic latex-based materials. Some will come with the ability to ward off mildew and rust in the future as well.

As mentioned earlier, copper requires a unique primer. Some types of copper siding oxidize and create a unique patina over time, making them difficult to paint in the long term.

6. Select Exterior Acrylic Paint

Choosing your exterior paint will be the most important step of this process. Oil-based paint will likely be your best bet, but like paint primer, choose a specific product ideal for metal siding. 

Your paint must be marked for exteriors, have at least a satin sheen, and preferably include rust or mildew resistance. While some acrylic paints also work on metal siding, be sure to choose one made for difficult materials to avoid streaking.

7. Wait for Ideal Painting Conditions

While ideal weather may not always line up with your DIY weekend, it's best to avoid a few conditions. The best time to paint your house is during moderate temperatures without any rain or snow in the forecast. Start early in the day to give your paint the best chance of drying under consistent temperatures before the sun goes down as well. Additionally, whenever possible, avoid days with large gusts of wind to avoid streaking and debris getting in the way of your perfect finish.

8. Move Slowly and Evenly

The most important tip for painting metal is to take your time. You can use either a roller or an airless sprayer. When adding either your primer or paint, add several thin, even coats instead of moving too quickly with a thick coat all at once. Stay consistent, moving from the same side of the house to the other each time for even and clear lines without streaking.