What is the difference between structural steel and light gauge steel?

Light Gauge

This steel is cold formed, which creates long, thin sheets that are then shaped into guided “C” or “Z” patterns capable of holding heavy loads. Light gauge supports come in a galvanized finish of zinc, aluminum or a combination of the two. For this construction process, a load-bearing wall is constructed first, then interior partitions and exterior cladding follow.

Light gauge is most commonly used in residential or light commercial construction as an alternative to wood framing. It’s similar to wood in that little cutting and sizing is required on the job site because the studs are manufactured to precise lengths. However, light gauge steel won’t rot, warp, burn or harbor insects like wooden frames. Due to their strength, light gauge steel frames also require less studs because they can be placed further apart. In general, light gauge will produce less waste, which is more environmentally friendly and more cost effective than alternatives like wood. Its main disadvantage is in case of fire, rather than burning, the steel structure will lose some of its stability and there is potential for collapse.

Structural Steel

Structural steel is hot rolled, and once hardened it becomes incredibly strong. For comparison, a one-inch circular bar that is firmly attached to supports can hold 20 tons. Structural steel is used in heavy duty construction projects such as multi-story buildings, bridges and industrial plants. Its strength and flexibility allow it to withstand moderate seismic activity, heavy traffic loads and high winds.

While concrete and stone can be used in similar projects, structural steel is able to provide stability and strength at great heights unlike the alternatives. However, when combined with steel, concrete can provide a higher level of support for large infrastructures.

The downfall of structural steel is its weight. It requires heavy trucks for transportation and must be placed with cranes. For this reason, structural steel is rarely used in residential or light commercial construction because it’s cumbersome and expensive. Medium-size commercial construction can use either light gauge or structural steel, it just depends on the needs of the project.

Structural steel and light gauge framing are quite different in both production of the steel, application and fastening methods. Structural steel requires thicker and heavier fastening methods, such as welding, bolting or riveting. Light gauge steel on the other hand can be fastened more simply with steel screws.