Beneath the Surface: Evaluating Hot-Dip Galvanized Steel Underground

Whether in the atmosphere, submerged in water, or embedded in soil, there are many different corrosion mechanisms that impact the longevity of hot-dip galvanized steel. Most commonly hot-dip galvanizing is used to protect structures exposed to the atmosphere. The corrosion mechanisms in this environment as well as the life expectancy of hot-dip galvanized steel have been studied thoroughly and proven through structures that have been in place for decades. However, when it comes to soil and water applications, the corrosion factors and life expectancy can become much murkier. 

Q: I’ve heard some types of “galvanized nails” specified for building/roofing projects can rust after only a few years in service. Which zinc-coated nails will provide the longest corrosion protection?

A: Often when purchasing zinc-coated nails, there is a misunderstanding about the difference between the methods that can produce a zinc coating on steel. There are four common methods used to coat nails with zinc: hot-dip galvanizing, tumbler hot-galvanizing, electroplating (electro-galvanizing), and mechanical zinc plating (peen-plating). Knowing the differences between these methods is valuable when assessing the corrosion protection required for a project.