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The core components that make up a pre-engineered metal building

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The core components that make up a pre-engineered metal building

Standard prefabricated steel buildings are comprised of several different components which are all engineered and manufactured at one of our state-of-the-art facilities and delivered to your job site location for quick and easy assembly. Because pre-engineered metal buildings are designed by an on-site engineer, each component is designed and detailed to be pre-cut, pre-welded and pre-drilled, leaving little room for quality and / or assembly issues. This is a key benefit of pre-engineered steel buildings.

While we are primarily considered a metal building supply company, we also provide the highest quality components as either individual or replacement materials. This guide will walk you through the core components of your steel building, offering considerations for those who may be designing an all-steel building — or for those who are just planning to order components.

Primary framing components of pre-engineered steel buildings

The primary framing of pre-engineered metal building is made up of two or more rigid frames depending on the building length. A rigid frame has two columns and two rafters which form the basic shape of your building. These I-beam columns and I-beam rafters can be either straight or tapered. These frames are placed at regular intervals along the length of your building; typically 20’, 25’ or 30’ intervals. The interval in between each rigid frame is called the “bay spacing.” Common frame types include gabled (either clear span or with columns), single-slope or lean-to.

Interior rigid frames are designed to support half of each of the adjacent bays. Endwall framing is typically a more economical post-and-beam design, intended to support half of the first bay only.  If you plan to add onto your building in the near future, you might consider a rigid frame expandable endwall, which will function like an interior rigid frame with the capability to support half of the next bay you add.

Pre-engineered steel buildings can be designed clear span up to 150’ using standard engineering tools.  Additional engineering makes it possible for these buildings to be clear span up to 300’ wide. For buildings approximately 80’ or wider, it may be more economical to add load-bearing columns at each interior rigid frame; however, it is important to consider the additional cost for concrete footings at each of these columns.

Your building’s primary framing components can be customized to meet your budget and the needs of your application. For diagrams and further explanation on primary framing and the rest of the components comprising pre-engineered metal building, read this steel building anatomy guide.

Secondary framing components: Purlins, girts and eave struts

Girts, purlins and eave struts are the secondary framing elements that run perpendicular to each of the I-beams that make up your rigid frames. Depending on the design, these are required for added structural stability. Pre-welded clips on the primary framing members make it easy to attach your secondary framing.


Girts run from column to column around the perimeter of your building. They are installed parallel to the ground, providing support for your wall panels.


Purlins run from rafter to rafter in a similar manner as girts but are specifically designed to support roof systems.

Eave Struts

Eave struts are placed at the juncture between your wall and roof, where purlins begin and girts stop.

Standard girts, purlins and eave struts are made from 12-, 14- or 16-gauge steel and are typically 8” deep. Both gauge and member depth can vary depending on the span between main frames, area wind and snow load requirements and any additional loads that might be imposed on the building. Extreme load requirements may necessitate 10” or 12” secondary members.

All secondary framing elements are designed and engineered specifically to your building’s size, application and load requirements. You may also order secondary framing components separately for individual or replacement purposes.

Steel building bracing options: X-bracing, wind columns and portal frames

Your building needs an engineered bracing design to help it withstand wind and snow loads and the forces of holding up the building itself. You will need to brace at least one bay on each wall of your building, and provide flange bracing for your roof. Bracing components come standard with your Searcy Building Systems purchase.

There are three ways to brace your building: X-bracing, wind columns and portal frames.

In X-bracing, you stretch two steel rods or cables in an “X” shape across your bay. While this is the least expensive bracing option, you cannot install any accessories such as doors or windows in a bay that contains X-bracing.

Wind columns and portal frames allow you to keep the bay open, meaning you can install a window or door in the space. While wind columns typically cost less than portal frames at first glance, a wind column requires more concrete under its pier footing than a portal frame. Therefore, while a wind column can make the building price appear to be lower, it can end up costing the customer more in the long run.

When engineering your bracing design, a metal building distributor will consider the components your application requires and lay out your building in the most cost-effective way.

Steel building roof and wall panels

26-gauge purlin bearing rib (PBR) roof and wall panels —the most economical, durable option on the market— come standard on each and every building. Each PBR panel laps over the adjacent panel, providing exceptional leak protection for a weather-tight building envelope.

There are several options for wall (architectural or A-panels) and roof panels (standing seam). There are several different reasons to go with different panel profiles, types and gauges — if you are looking for a premium or different look, if your project requires a standing seam roof in order to meet the local energy code or if your building design requires a higher gauge seamed roof system. Panels may also be optional in the event that the design involves brick, block, stucco or another exterior finish. In this case, the building is designed with designated walls open for masonry with the required deflection limits included in the design. Furthermore, even if you simply need panels as individual or replacement materials, we are happy to quote the panels, closure strips and fasteners delivered to your jobsite. Feel free to give us a call.

Framed openings for doors and windows

If your building has walk doors, roll-up doors or windows, you will be supplied the framed openings, full cover trim, and exterior j-trim to give your building a more complete and finished look. Metal building accessories such as personnel doors, roll-up doors, skylights, ridge vents and windows can be added to your pre-engineered building upon request or ordered as needed.


Your pre-engineered metal building will come with all the fasteners, clips, nuts and washers needed to assemble the individual components described above. Each component will come with pre-drilled holes, so you or your erector will just have to put each fastener in the right place.

Building drawings and anchor bolt plans

Stamped and certified building and anchor bolt plans are another standard component of pre-engineered metal buildings. Metal building drawings are detailed depictions of your building design and each of its individual components. The anchor bolt plan and building reactions show where to set your bolts within your concrete pad / foundation. It includes the required diameters of the bolts, the projection needed so that the concrete contractor can calculate the overall length of the bolt and the steel reactions depict the forces your building system will have on the slab.

Customizing your pre-engineered metal building components

Although we do not consider ourselves a metal building components company, we do design and deliver the highest quality components — either as part of a building package or an individual order. Our experienced building consultants will work with you to design the building and components that meet your exact specifications in the most economical way possible — but we will never sacrifice quality to get the lowest price. Your building’s components will be custom-designed to meet the size, design and code requirements of your application.

A standard metal building system from Searcy Building Systems is far from standard. With 20-year panel warranties, a fully engineered bracing design and stamped and certified building plans, your building will not only serve its intended application but stand tall for years to come. If you are ready to talk with one of our consultants about designing a building or placing an order for components, request an obligation-free consultation today.