Should You Be Worried About Rust on Cast Iron Grates?

Cast iron grating is a popular material for trench drain systems. Its durability, resistance to corrosion, and versatility allow it to be used in areas where heavy equipment, water flow, or high traffic is common.

That being said, every material has its benefits and downsides. At The Trench Grate Store, we often get questions about rust when it comes to cast iron. So, in this post, let’s talk about identifying rust on cast iron grates and whether you should be alarmed.

Cast Iron Grating 101

Cast iron drain grates are manufactured using several molded bars. Cast iron grating is incredibly durable, and can withstand heavy vehicles and traffic. In fact, we offer cast iron grating with ratings of H20 and higher.


Cast iron is incredibly easy to clean, which allows you to keep work areas sanitary. Cast iron handles water and waste runoff. This versatile material handles high amounts of water or waste to allow them to drain into your system underneath without issue.

Perfect For Residential and Commercial Usage

Whether you’re using cast iron grating for shower drains, floor drains, area drains, or trench drains, their oxide coating will withstand rust from water and weather patterns.

Do You Have Rust on Your Cast Iron Grating?

Raw cast iron grates quickly lose their silver color and turn red or orange once rust begins to form from moisture.

The cause of this is oxygen atoms that bond with iron atoms and create iron oxides. Unlike other materials, you shouldn’t be alarmed if you notice your cast iron grate rusting. It will eventually settle into a rich dark brown, and often comes this way.

In raw cast iron grates, saltwater spray can also have an impact on rust for cast iron as well as harsh chemical exposure. Once rusting has begun, an iron oxide silicate layer will give the cast iron a form of protection against additional corrosion from the environment.

However, if the layer is broken or chipped, then the iron can be weakened by further oxidation. Still, a slow darkening to a natural dark patina is expected over around two years.

Get Cast Iron Grating Today

At The Trench Grate Store are experts in providing cast iron grating in a variety of shapes, sizes, and load capacities. No matter what you’re installing a trench drain system for, the right grating is crucial.

 If you have any further questions, give us a quick call to talk to one of our grating professionals. Let us help to insure your project moves forward safely, and effectively.