Once corrosion starts, it spreads. Oxygen, moisture, salt, and dirt work together to slowly wear down even strong metals. It’s a quiet kind of damage that’s easy to miss until it becomes a problem. At Alummikon Stairs, we build outdoor aluminum stairs that stand up to tough conditions, but it’s still important to stay ahead of wear and tear. Here's what to look for, what causes it, and how to deal with it before it affects the safety or structure of your outdoor stairs.
Common Corrosion Challenges for Outdoor Metal Steps
Common Corrosion Challenges for Outdoor Metal Steps
Salt Exposure During Winter
Salt is one of the most aggressive triggers of corrosion on outdoor stairs. When road salt or de-icing products land on metal steps, they cling to the surface and pull in moisture. This can lead to pitting or surface corrosion, especially in the joints and fasteners. Rinsing your stairs regularly during winter helps wash away buildup before it starts to cause damage.
Trapped Moisture in Hidden Areas
Even aluminum isn’t immune to trouble when moisture gets stuck between components. Tight corners, undersides, and connection points can trap water, especially during freeze-thaw cycles. This constant exposure creates ideal conditions for corrosion to begin. Good drainage and regular clearing under and around your stairs can go a long way in preventing this.
Scratches that Expose Bare Metal
Every ding, scrape, or chip in the finish gives corrosion a head start. Once the protective coating is damaged, moisture and oxygen have direct access to the metal underneath. Small scrapes may not seem serious, but they can snowball fast. Touch up those spots as soon as you notice them using a matching outdoor-rated sealant or paint.
Galvanic Corrosion from Mixed Metals
When two dissimilar metals touch and moisture is present, it can create a slow chemical reaction that eats away at one of them. This is called galvanic corrosion. It often showed up where hardware made from steel or copper contracts aluminum components. Using compatible materials and checking joints helps prevent long-term issues.
Poor Ventilation Around the Base
Lack of airflow around the base of outdoor stairs creates pockets of humidity, especially in shady or low-lying areas. Moisture that lingers around the footings increases the risk of corrosion where the metal meets the ground. Trimming nearby vegetation and keeping the space beneath your stairs clear helps keep things dry.
Airborne Pollutants & Acid Rain
In industrial areas or near highways, outdoor aluminum stairs are exposed to pollutants that mix with rain to create a mild acidic film. Over time, this can dull the finish or cause minor etching on metal steps. A seasonal rinse with mild social and water helps clean off residue before it settles in.
Corrosion builds slowly, and the earlier it’s spotted, the easier it is to stop. If metal steps go uninspected for months—or worse, years—you’re more likely to face costly repairs or replacements. Set a seasonal reminder to walk through your stairs and give them a once-over. For new steps, connect with Alummikon Stairs today!