Different Types of Materials Used in Manhole Covers

When most people think of manhole covers, they think of the standard metal ones commonly seen around town. However, there are many different types of materials used in manhole covers that many people don’t know about. That’s why we’re going to go over all of them in this blog post.

Cast Iron

The metal manhole covers you are most accustomed to seeing are cast iron. There are two types, though. The gray cast iron covers are made by pouring the iron into a mold along with some carbon and silicon, giving the lid its usual strength and durability.

The other type is ductile cast iron. It’s much stronger since it is commonly used at airplane terminals or other places with heavy vehicles. It gets crafted in the same way, but manganese gets added to the mix to force the carbon to form nodules instead of their standard flakes, adding to the lid’s rigidity.

Carbon Steel

This is the other primary type of metal-based manhole cover. While carbon steel isn’t as tough as iron, it’s made to be much lighter for easy removal while still being strong enough to keep heavy objects out. If this sounds like a combination that would be a good fit for your yard, be sure to check out the round sewer lids we offer on our website.

Concrete

Another common type of material used in manhole covers is concrete. These mostly get used when trying to make a cover blend in with the ground surrounding them, usually in nicer towns or upscale shopping centers. Even though they are quite strong, they deteriorate over time. This deterioration happens much quicker than most metals, which is why many concrete manhole covers get reinforced with cast iron around the edges.

Composite Materials

The last main type of manhole cover is made out of many different types of plastics, fiberglass, and other composite materials. They’re commonly used in Europe. Their appeal comes from their light yet sturdy build. Their color can also be changed freely. Despite their sturdiness, though, they’re by far the weakest and are susceptible to breaking under immense amounts of friction.