Types of Steel Used in Construction Projects

Steel is famous for its unparalleled strength and versatility. It stands out from other construction materials due to its unique ductility properties and high tensile strength. Its structural integrity, coupled with its low cost, has made it one of the core materials needed for any construction project, be it commercial or industrial.

The applications of steel are countless, ranging from reinforcing bars to steel sheets. Since there are over three thousand different grades of steel available in the market, the specific type of steel used in a construction project depends on the nature of the project. However, there are a few varieties that are more popular than others due to their unique features. Below we have jotted a guide on the four main types of steel favored by the construction industry:

  • Rebar Steel

Image showing two bundles of rebar.

Shorthand for reinforcing steel, rebar steel is a steel bar or mesh of steel wires usually made from carbon steel. It is often used as a tension device in masonry structures and reinforced concrete (RCC) to provide additional strength. 

Although the most common rebar type is carbon steel, stainless steel and composite bars made of carbon fiber, basalt fiber, and glass fiber are also readily available. Hot-rolled round bars with deformation patterns on their surface are typically used to improve the bond quality with concrete and reduce the risk of slippage under tension. The bars are often also coated in epoxy resin to increase corrosion resistance. 

The main purpose of rebar in construction is to enhance the properties of concrete. While concrete can withstand compression to great lengths, it has little strength under tension. Therefore, rebar is cast into concrete to improve the overall tensile strength, making it possible for the structure to withstand heavy load pressure. 

Rebar steel is ideal for reinforcement with concrete since both have similar coefficients of thermal expansion. Due to this, a concrete structural member reinforced with rebar steel does not buckle or experience minimal differential stress when the temperature changes.

Rebar steel improves not only the tensile strength of concrete but also its durability. Stainless rebar steel, in particular, is famous for its high durability. It can withstand repeated abrasion and scraping during construction, making it one of the most durable types of steel. This ability makes rebar steel ideal for use in reinforcement. 

Adding to the functionality of rebar as reinforcement steel is the fact it is reusable. Like other metal products, rebar can also be recycled as scrap. In various countries, workers remove rebar from a concrete structure once it is demolished. The extracted can be melted down, combined with other steel products, re-purposed, and reused, making construction projects more eco-friendly. 

  • Light Gauge Steel

Also known as cold-rolled steel, light gauge steel is a cold-formed construction material rapidly growing in popularity. As the name suggests, this steel type is known for its lightweight characteristics. It is not bulky like structural steel or heavy like concrete. Light gauge steel is shaped in a cold process where thin sheets of steel are guided through a series of rollers into specific section profiles. The construction industry is embracing this strong and light framing material as it makes the building process easy for everyone, from the architect to the developer. 

One of the notable selling points of light gauge steel is the versatility it offers. It can be manipulated and molded into a myriad of shapes and forms and insulated with a broad range of materials. Moreover, you can also change or modify it at any point in its lifespan.

Compared to other steel varieties, LGS is lightweight and easy to carry around the construction site. It allows fast construction without requiring heavy tools or equipment to move the framing material as all components can be carried by hand. The ease of handling makes it an ideal option for construction projects that have tight completion deadlines. Moreover, its usage creates a safer environment for workers as the risk of injury due to impact or carrying heavy loads is drastically reduced. 

Light gauge steel is a cost-effective option as it cuts down bills in many ways. Due to its easy handling, you will require fewer laborers to carry it around, allowing for significant savings in terms of labor. You will also save time as it allows for fast construction. All in all, it is highly sustainable due to its affordability. 

  • Mild Steel

Carbon steel is one of the four main types of steel that contains carbon as the only alloying element. Mild carbon is a carbon steel variety that comprises about 0.04%-0.30% carbon content. It is the most commonly used steel variety in the construction industry. 

Mild steel is known for its hardness and strength. The carbon content in steel is directly proportional to its strength and hardness; however, the harder and stronger the steel is, the less ductile it will be. Since mild steel has a lower carbon content than other carbon steel varieties, in addition to being strong, it is also very flexible, which prevents it from cracking or buckling under pressure. It can withstand great seismic movements due to its ductility, making it the top material choice for construction in areas prone to earthquakes. 

Mild steel comes in a variety of shapes ranging from structural beams to flat sheets. Other alloying elements can also be fused with it to produce desired properties. Due to its high versatility and customizability, it has become the most common form of steel. It is typically used in construction projects where large quantities of steel are needed. Its low price serves as the cherry on the cake, making it the go-to material choice for both commercial and industrial construction projects. 

  • Structural Steel

Image showing various structural steel shapes.

Structural steel is another popular type of steel mainly used for making construction materials in a myriad of shapes and sizes. Some of the most common structural steel varieties include T shaped, I-beam, L shape, Channel Sections, Plate type, and Z shape. Each kind has its distinct shape or cross-section and compositional properties, making it ideal for specific purposes in construction projects. The composition, strength, and size of structural steel are often controlled in most industrialized countries. 

Image showing the Golden Gate bridge of San Francisco.

Construction projects, including high-rise buildings, depend heavily on structural steel as it is used in the base of the building. Other than bridges and transmission towers, structural steel is also an ideal option for light construction work. 

One of the reasons structural steel is the top choice of material for commercial and industrial building construction is its strength. It stands out from other construction materials due to its toughness, stiffness, high strength, and ductility. Moreover, structural steel is also known for its high level of constructability. You can develop it into almost any shape and size. Concrete requires curing for several days after pouring before it can be erected. On the other hand, structural steel can be welded and used immediately, making it a schedule-friendly material. 

Most structural steel varieties used in construction are resistant to water and corrosion. However, extra measures are still taken to prevent any lifetime corrosion. For instance, painting the steel provides water resistance while protective coatings like aerosol sprays and galvanizing prevent corrosion.

Structural steel is the go-to construction material choice for environmental advocates.  It can be repurposed and reused with ease, making it an environmentally friendly option for industrial and commercial construction projects. When buildings are demolished, workers retrieve all the structural steel and customize it for reuse, promoting green construction. 

The Takeaway

Image showing cranes on a construction site. 

Each steel type has a specific unique set of properties. Depending on the nature of the construction project, a steel variety can either add value to the building or lowers its structural integrity. Therefore, before you decide on any steel type for use in your construction project, make sure that its properties complement the requirements of your structure. Considering factors like tensile strength, cost, corrosion resistance, and eco-friendliness will ensure that you select the type of steel best suited for your construction project.