Rain Erosion: What Causes It and How Can It Be Repaired?

Rain erosion, also known as erosion corrosion, is a type of material degradation that occurs when rainwater, combined with other environmental factors, damages the surface of materials over time. It can be especially troublesome with outdoor structures and heavy equipment.

Causes of rain erosion

Because the rain is rarely purely water, rainwater itself can cause erosion when it carries abrasive particles or corrosive substances, such as dust, sand, salt, or pollutants. Raindrops can dislodge protective coatings or create small surface defects when they hit a surface.

Rapid temperature changes can cause an expansion and contraction of materials. This can weaken protective coatings and contribute towards rain erosion.

Coastal areas are particularly prone to rain erosion, where wind-driven rain can exacerbate erosion via salty sea water. This salt can accelerate the corrosion of metal surfaces.

Repair and prevention of rain erosion

Applying or reapplying protective coatings, such as paint, sealants, or anti-corrosion coatings, is your best bet for helping to prevent rain erosion, as these coatings act as a barrier between the material and the environment.

When building an outdoor facility, it’s best to choose materials that are resistant to corrosion and erosion. Stainless steel, aluminum, and weather-resistant alloys are all good choices. It’s also a good idea to regularly inspect structures and equipment for signs of erosion and corrosion is critical. Early detection through rain erosion tests allows for timely repair or replacement of damaged parts.


Rain erosion can be a persistent challenge in outdoor and exposed environments, especially when it comes to keeping materials damage-free. The most effective approach is to combine preventive measures with regular inspection and maintenance to minimize the impact of erosion and prevent extensive damage. In cases of severe erosion, it may be necessary to consult with specialists in materials science and engineering to develop appropriate repair and prevention strategies.