Galvanized steel can be a tricky substance to paint. Without proper prep work, the paint will inevitably flake and peel. When a homeowner’s galvanized metal railings were flaking heavily, paint expert Mauro Henrique knew it was caused by a lack of prep. Together, Mauro and the homeowner chip off the existing paint, clean the railings, and prime them before painting for a perfect finish.
How to Repaint a Galvanized Steel Railing
- Place drop cloths over anything you want to protect, including the porch and steps, garden, and walkway. Protect the door and walls with a self-adhesive plastic dropcloth, as well as the sides of the steps.
- Wearing your safety glasses, start chipping and scraping away the existing paint. A putty knife will chip most of the loose paint off, while a painter’s tool has a sharper point that can get under more stubborn paint. A scraper has an even finer edge, essentially cutting the paint from the surface.
When homeowner Dawn reached out to This Old House about her galvanized steel railing — installed just five years earlier — the paint was already blistering and blowing off. Painting expert Mauro diagnosed the problem immediately: “It was not prepped right, or they might be using the wrong paint for that.” His fix? “We’re going to have to strip down the whole thing, clean it really well, and then apply the right paint on it.”
Quick tips: Around the balusters, it can be easier to break the edges of the paint by dragging the pudding knife down the edges first. For paint stuck in corners and crevices, use the point of the painter’s tool to tap the paint loose. Also, if the paint doesn’t chip off easily, you might need to use a power sander with 220 grit sandpaper.
Pro Tip: Mauro Henrique, This Old House painting expert, cautions against reaching for power tools too quickly: “It would be easier, but… a sander will damage the zinc coating on this metal.” A putty knife is gentler on the galvanized surface and, with the right technique, just as effective at removing loose paint.
- Once all the paint is removed, put on a pair of nitrile gloves and use a light scrub pad and denatured alcohol to clean the entire surface of the railing. This will remove any residues and other substances that can prevent the paint from adhering.
- Apply a coat of primer to the railing. Use a brush to apply it in areas that are hard to reach and a paint roller with ¼-inch nap cover for the other areas. Use long, smooth passes with the roller where possible. Make sure to prime the entire railing, as missing a spot can result in paint flaking again. Allow the primer to dry for an hour.
- Paint the railing with the DTM paint using the same techniques. Use a brush for corners and crevices and the roller for the longer, flatter areas. Allow the first coat of paint to dry and then apply another coat.
Pro Tip: Mauro Henrique, painting expert on Ask This Old House, explains why denatured alcohol is the go-to cleaner for this step: “Because it cleans better and evaporates” quickly, leaving no residue behind that could interfere with the new finish.
DTM paint should adhere nicely to the primer and create a long-lasting finish. However, dark colors often apply as a dark, hunter green. It will dry as the proper color. In Mauro’s experience, with proper prep work, you’ll only need to paint the railing again if you decide to change the color.
Pro Tip: Mauro Henrique, This Old House painting expert, advises using long, continuous strokes when applying paint to railings: “Just go nice and smooth in one long stroke. Don’t stop and go. Just go all the way up there and then come back. If you see a spot that you missed, just go up there and fill it in.”
