An assortment of purlin styles is available for use pre-engineered steel building systems. All roofing systems are not alike, so it is important to understand which purlin method is best for your building. In the early 1900s, roof framework assembly consisted of hot-rolled channel and I-beam purlins that spanned roof trusses. Eventually, hot rolled steel purlins in steel structure systems came into use as the prevalent support system. Today, this technique is still utilized for all-steel structures, especially in manufacturing facilities needing a lot of interior support. As compared to lesser gauged designs, the increasing adoption of hot-rolled steel beams is in large part due to their superior load sustaining features. The beams themselves can be used to traverse 30 feet or longer. Hot-rolled purlins can also support hefty overhead building loads throughout the interior of the building. However, this approach can be more costly.