By Jesse Sanchez. 

Understanding framing, load paths and real-world testing helps ensure your project is a code-compliant and durable metal-over-metal retrofit. 

When an existing metal roof reaches the end of its service life, retrofitting is often the easiest, least invasive and most cost-effective replacement strategy. Companies such as Roof Hugger emphasize that beneath every successful metal-over-metal project is a structural story that cannot be overlooked. Understanding the roles of purlins and subpurlins is essential to delivering a high-quality, code-compliant and long-lasting new roof. 

In older pre-engineered buildings, purlins are typically spaced five feet on center, eight inches deep and formed as Z-shaped members spanning from frame to frame. Many are continuous-span members that overlap at frames and act together to distribute loads. Their bracing needs depend heavily on the roof system above them. Through-fastened panels can provide diaphragm strength, often reducing additional bracing, while standing-seam systems offer minimal diaphragm support and require more structural reinforcement.  

During a retrofit, two structural issues must be addressed: performance and weight. Panel clip spacing must be analyzed for code-compliant attachment, and panel behavior can vary significantly when fastened to subpurlins instead of full-depth purlins. Additional loads, including photovoltaics or rooftop equipment, must also be evaluated against existing capacity.  

Notched subpurlins are often the most cost-effective framing option because they minimize added height and dead load. However, subpurlins are not the same as purlins. Differences in steel grade, flange size and geometry directly affect uplift and pullout performance. Some suppliers use lower yield Grade 30 steel, which can reduce pullout values by as much as 50%.  

Because panel combinations, gauges and framing variables vary widely, computer simulations alone are not enough. Testing under standards such as ASTM E1592 and AISI S908 provides the validated data needed to make informed decisions. In metal retrofit design, real performance testing, not theoretical modeling, ultimately protects both the structure and the owner’s investment. 

Learn more about why purlins and subpurlins matter in metal retrofit design and how proper analysis, material selection and validated testing protect structural performance and long-term investment!

Honoring Mark's life and accomplishments.

We are deeply saddened to share that my longtime pillar of the metal building community Mark James passed away on Sunday, March 22, 2026. Mark is survived by his wife of 55 years Paula, his son Jarrod, his grandchildren Brooklyn, Harley, Julian and his great-grandson Trevon. A service will be held in Dallas in the near future.

Mark’s career began remarkably early. At just eight years old, he worked as a blueprint boy for his father’s company. He later attended the University of Missouri and continued his education at night through the Finlay School of Engineering in Kansas City, Missouri.

In the late 1970s, Mark designed roof systems using dimensional lumber to retrofit flat roofs with truss-framed sloped roofs — Ultimately contributing to more than 30 million square feet of retrofit projects. In 1981, he was recruited by Kirby Building Systems as their Special Projects Manager, prompting a move to Houston, Texas. In 1984, he accepted a district manager position with United Structures of America, and four years later, in 1988, he became a partner in Genesis Group, Inc. of Baton Rouge, where he worked on both new metal buildings and retrofit projects.

Moving now to Dallas, Texas, Mark joined Roof Hugger, Inc. in 2009, where his impact was immediate and lasting. He developed standard details, product specifications, sales presentations and represented the company at numerous industry association meetings. He became deeply involved in the Metal Construction Association (MCA), eventually serving as chairman of the retrofit council. In that role, he helped create many of the AIA education programs that continue
to be used today.

He was a familiar face at RCI (now IIBEC), MBCEA and other industry organizations. Mark also played a major role in creating and setting up many of the METALCON Live Demo displays, including the Metal Roofing Games Competition and the Solar Bay exhibit. To say he was well known in our industry is an understatement.

After retiring from Roof Hugger in 2014, Mark founded his consulting firm, RetroSpec, LLC, continuing to advise Roof Hugger, MCA and many other metal-related companies. He and Paula then moved to Hot Springs, Arizona, where they enjoyed a beautiful home and surroundings and after buying a large camper, they traveled across the country while he continued consulting remotely.

In 2019, Mark received MCA’s prestigious Larry A. Swaney Award, recognizing his commitment to communication, cooperation, unity and the advancement of the metal construction industry. Beyond his professional achievements, Mark was an accomplished artist, cabinet maker and interior designer. He loved his family deeply, and those of us who knew and worked with him will miss him profoundly.

By Jesse Sanchez. 

How retrofit testing is redefining metal roof performance and why documented, real-world structural testing is essential. 

Metal building owners are asking a more direct question than they did a decade ago. The issue is no longer simply whether a roof can be replaced, but whether the existing structure can handle added weight, comply with current codes and support future rooftop systems such as solar. That concern is pushing the industry to focus on structural retrofits that are tested, measured and documented. On this episode of MetalCast™, Dale Nelson and D.J. Highnote of Roof Hugger explained how testing changed the way retrofit performance is evaluated. They emphasized that if a system claims to strengthen a building, it must prove it. 

Dale said the company’s approach began with a hard lesson in the field. “It was structurally not correct, but that's all we knew to do at the time,” he said, describing early overlay methods. That realization led to the creation of a notched Z component designed to create a direct structural connection into the building frame. Still, observation was not enough. Crews noticed stiffer roofs after installation. “After you put the roof hugger on, it didn't spring anymore,” Dale said. But building owners and engineers needed more than feel. They needed data. 

To provide it, the company constructed a 50-foot multi-span test bed to simulate real building conditions. “We did over 30 tests of various gauges, profiles, heights of parts,” Dale said. D.J. emphasized why that mattered. “If you can imagine taking on this project of building a 50-foot long test bed, which is going to be a multi-span Perlin, which is what a metal building is really going to be,” he said. The goal was to mirror actual building behavior, not idealized lab conditions. 

The result is documented capacity increases supported by sealed engineering calculations that engineers can review and verify. As D.J. put it, “Not every test goes the way you think it's going to,” a reminder that real performance is uncovered through repeated testing, not assumptions. In today’s market, structural strengthening cannot rely on reputation or field impressions alone. It must be tested, calculated and clearly proven. 

Listen to the podcast or Watch the interview to learn more about how retrofit testing is redefining metal roof performance and why documented, real-world structural testing is essential. 

By Emma Peterson. 

Join The Coffee Shops™ crew and our industry partners in Sacramento for four days of education, innovation and industry connection. 

The Coffee Shops™ crew is putting the finishing touches on our travel plans to get to Sacramento, California March 12–15, 2026 for the International Institute of Building Enclosure Consultants (IIBEC)’s International Convention and we want to see you at our booth and soundstage, sponsored by Western Colloid!  

This year’s show is predicted to host “1,700 consultants, architects, engineers, design professionals and other experts” for four days of learning, networking and more! With national sponsors like Carlisle, Elevate™, GAF, IB Roof Systems™, Johns Manville, Polyglass USA Inc., Sika Corporation, SOPREMA and Versico, this show is a must-attend for professionals in all parts of the roofing world.  

Expert-led education  

This show gives attendees a chance to learn from a variety of industry leaders and experts through their cutting-edge education sessions. Here are some of the incredible presenters that will be at this year’s show:  

• Trent Cotney of Adams and Reese will be hosting a “State of the Industry” session that will explore contract provisions and other emerging regulatory trends.  
• Darren Perry of SOPREMA has a session that discusses how low slope roofing can be enhanced in response to severe climate risks. 
• Amrize’s National Technical Manager Victor Rosenthal and Project Manager Rachael DeMeio will be teaching about trends in roof re-cover applications this year. 
• Jennifer Stephan from Benchmark’s session will dive into the world of Refrigerated Processing and Cold Storage Operations in relation to industrial roofing projects.  

Check out the full speaker list online!

An expo floor route 

The Coffee Shops crew will be on the expo floor hosting a soundstage at booth #1113! Here’s just a few of the other Coffee Shops friends and partners that can be found on IIBEC’s 2026 International Convention expo floor:  

• All Weather Insulated Panels (booth #1216) 
• Anchor Products (booth #907)  
• ATAS International (booth #728)  
• BITEC Inc. (booth #1023) 
• Brava Tile (booth #208) 
• CertainTeed (booth #227)  
• General Coatings Manufacturing (booth #926) 
• H.B. Fuller (booth #113) 
• ICP Building Solutions Group (booth #133) 
• IKO Industries (booth #426) 
• Leister (booth #619) 
• Malarkey Roofing Products (booth #213) 
• MuleHide (booth #814) 
• Roof Hugger (booth #707) 
• S-5! (booth #1019) 
• Sheffield Metals International (booth #625) 
• Sherwin Williams Roofing Solutions (booth #422) 
• Tremco (booth #321) 
• USG Securock (booth #401) 
• Western Colloid (booth #923) 
• Westlake Royal Roofing Solutions (booth #433) 

Explore the full expo floor map!

Register today and make sure you stop by to say hi to us and our industry friends at the IIBEC’s 2026 International Convention!

By Jesse Sanchez. 

A company built on a dedication to quality and craftsmanship finds new ways to make old metal buildings feel safe again. 

As shared on this episode of Roofing Road Trips®, Dale Nelson, founder and president of Roof Hugger, joined vice president D.J. Highnote to discuss how a structural problem led to a new approach to metal retrofit. When Dale first began retrofitting metal buildings, the standard approach was straightforward: lay hat channel across the high ribs of the existing roof and fasten it down. It was common practice. But Dale said it was not structurally sound. “The usual approach wasn’t structurally correct,” he said. “We needed something that connected straight down into the structure below.” 

That realization led to the development of the notched Z, a structural member designed to sit over the existing metal panel and fasten directly into the purlin below. Instead of relying on the old panel for support, the system created a direct load path into the building’s framing. As a result, the roof assembly behaved differently under weight and movement. 

“After you put the Roof Hugger on, it didn’t spring anymore,” Dale said. The reduced deflection confirmed that the connection was doing more than holding panels in place. It was changing how the structure responded under load. That observation prompted further testing. 

To measure the impact, Roof Hugger constructed a 50-foot-long, two-bay test bed to evaluate how retrofit components performed under controlled conditions. The company conducted more than 30 tests across different gauges, profiles and part heights. And engineers analyzed how each variation affected strength and deflection. 

The data was then incorporated into proprietary engineering software. Rather than evaluating only purlin capacity, the modeling accounts for the entire assembly, including laps, fasteners and connections; the components that often determine where a system will fail first. 

That emphasis on understanding the full structural system continues to shape how Roof Hugger approaches retrofit projects today. 

D.J. said structural clarity remains central to metal-over-metal retrofit, especially when contractors compare it to other recover options. “When they install TPO on a metal building, they’re considering that roof panel a deck and it’s not,” D.J. said. “It’s not a structural deck.” Metal buildings are engineered for channeled water flow along panel ribs. Water is designed to move quickly off the roof while purlins and panels deflect within controlled limits. When a flat membrane system changes that profile, drainage patterns and load distribution can shift, particularly under snow or ponding conditions. 

D.J. also noted that modern metal finishes often outlast rooftop solar systems. “That metal roof is going to last twice as long as the photovoltaic panels,” he said. “And they mount externally without penetrating the roof panel.” For building owners, a structurally connected metal-over-metal system provides strength, preserves drainage performance and creates a long-term platform for future upgrades. 

Listen to the podcast or Watch the interview to learn more about Roof Hugger and how retrofit testing shapes stronger metal roofs for long-term performance! 

By Jesse Sanchez. 

What Roof Hugger’s leaders say about the importance of purlin strength for aging metal buildings. 

Metal roofs are everywhere and as they age, owners must decide whether to patch, replace or upgrade their roof with long-term performance in mind. In this episode of MetalCast™, Roof Hugger leaders Dale Nelson and D.J. Highnote kept returning to one point: retrofit success depends on what happens at the purlin. If the structure underneath cannot safely carry added weight or meet modern load expectations, the roof above it likely won’t last as long as its expected roof life. 

D.J. framed the challenge in practical terms. “When we do a retrofit or an overlay, we’re adding weight. We already know a lot of these existing buildings don’t meet the new local loads,” he said. In many pre-engineered metal buildings, purlins were originally designed with tight tolerances and little excess capacity and as codes evolve and rooftop equipment or additional dead load is added, stress on those members increases. If the purlins cannot safely carry that weight, deflection rises and long-term performance declines. That is where Roof Hugger’s notched Z system comes in, creating a direct structural connection to the existing purlin or supporting member so the load path is reinforced rather than resting on aging roof panels. The retrofit framing works with the existing structure to help redistribute loads and increase capacity where it is needed most. Rather than assuming improvement, the company quantified it, emphasizing that credibility in the metal building world is earned through defensible data, not anecdotes and providing engineers and contractors with calculations that support informed decisions instead of guesswork. 

To document what was happening in the field, Dale said the company built a purpose-made test bed and ran over 30 tests across different gauges, profiles and part heights. The goal was not only to see whether purlins got stronger, but to understand where failures could occur across the assembly. “We have probably learned more from our test failures than we ever did out of our successes,” Dale said, explaining that each failure revealed where adjustments in geometry, gauge or connection design could improve performance. Those results were later used to refine part profiles and support modeling and engineered calculations, giving contractors clearer guidance on how much additional capacity a system could provide and where reinforcement was still required. 

For contractors and building owners, the challenge is that aging metal buildings were often engineered with little excess capacity and modern demands such as higher wind ratings, updated snow loads, rooftop equipment and solar, which push those limits further. Roof Hugger’s solution is not simply to cover what exists, but to reinforce it. Through controlled testing, measured load increases and engineered calculations, the company has developed a retrofit framing system that strengthens the purlins and restores confidence in the structure beneath the roof. That data-backed approach gives contractors something more than a product, it gives them documentation they can present to engineers, inspectors and owners. 

For building owners weighing retrofit options, purlin strengthening is not an add-on, it is the structural foundation that determines what a building can handle next, from code-driven loads to future rooftop upgrades. 

Listen to the podcast or Watch the interview to learn more about how purlin strengthening and real-world testing can transform aging metal buildings!

By Jesse Sanchez. 

A contractor-led idea grew into a widely trusted retrofit approach by responding to real-world challenges and validating performance through decades of testing. 

In this episode of Roofing Road Trips®, Karen Edwards sat down with Dale Nelson, founder of Roof Hugger, to trace how a practical field challenge evolved into a nationally recognized retrofit solution. Roof Hugger did not emerge from a boardroom strategy session or a market study. It took shape on an aging metal roof where conventional retrofit methods failed to meet structural realities, an experience that set the tone for the company’s direction after it was officially incorporated in 1991 and continues to influence how it approaches retrofit design today. 

Dale traced the origin of the system to his long professional relationship with Red McConaughey and a single reroofing project on an 8,000-square-foot building. At the time, the industry standard relied on rigid hat channels installed across existing roof ribs. While common, the method did little to accommodate metal’s natural expansion and contraction. When Dale questioned the approach, engineering guidance confirmed his concerns and made clear the solution would not perform long term. 

Rather than accept that limitation, Dale and Red looked for an alternative. The answer came in the form of a notched Z-shaped purlin that could connect structure to structure while still allowing the roof system to flex. Early fabrication costs were steep, but by working with fabricators on volume pricing, the pair produced workable prototypes. Those early retrofits performed as intended and the concept gained momentum through repeat projects. Dale shared, “We formed a corporation and off we went. We had rocking sales our first year of $9,600.” 

Building credibility became the next priority. After securing a patent in 1994, the company focused on education and visibility, leaning on industry publications and mentors to help communicate value in a market still defining retrofit standards. That outreach positioned the system as a practical alternative rather than a theoretical one. 

As Roof Hugger grew, its emphasis expanded beyond product development to industry engagement. Dale has pointed to association involvement as a turning point, providing insight into installer needs, manufacturer expectations and upcoming code changes. That perspective informed material choices, standardized specifications and a long-term commitment to testing. 

Testing soon became a defining pillar. With few formal protocols available in the early 1990s, Roof Hugger worked with engineers to develop its own methods before transitioning to established standards such as ASTM E1592. Continued research, including wind tunnel and purlin strength testing, revealed added structural capacity benefits that reshaped how retrofit projects could be evaluated. Dale stated, “You know, Red’s little idea really blossomed into something none of us could have imagined back in the early 90s.” 

Listen to the podcast or Watch the interview to learn more about Roof Hugger and its metal roof retrofit solutions!

By Jesse Sanchez. 

With millions of aging metal-roofed structures nationwide, strategic retrofits are reshaping value, resilience and long-term performance. 

For many owners who built metal facilities in the 1970s and 1980s, the priority at that time was affordability. These buildings were designed to provide what was often described as “shade and shelter,” allowing businesses to operate at the lowest possible cost. According to Roof Hugger, LLC President Dale Nelson, maintenance was rarely the focus as owners concentrated on staying afloat and navigating economic cycles. Today, those same buildings are often paid off, but they are increasingly out of step with modern codes, efficiency standards and operational expectations. 

That disconnect has created a new opportunity. Updated zoning requirements, stricter building codes and rising impact fees have significantly increased the cost of new construction. As Dale put it, “They don’t build them like that anymore.” With more than 1.6 billion square meters of metal-roofed buildings now between 20 and 50 years old, reinvestment has become an attractive alternative to starting from scratch. 

The most effective place to begin is the roof. Many early metal buildings relied on screw-down roof systems that paired 30-year panels with fasteners that often failed much sooner. These roofs are easily recognized by rows of exposed fasteners across the surface. Retrofitting the roof establishes a stable foundation for broader improvements, allowing owners to transition to standing seam systems and secure longer-term finish and weather-tight warranties. 

Roof retrofits also open the door to structural and financial benefits. Strengthening existing purlins can bring buildings into compliance with current codes, potentially lowering insurance costs while preparing the roof for future equipment such as solar. Dale also highlights the role of IRS Section 179 deductions and available energy credits in improving the return on investment. 

With the roof addressed, attention turns to wall openings. Older windows, overhead doors and personnel doors often fail to meet today’s performance standards. Modern replacements are engineered with reinforced components designed to reduce the risk of major structural damage. 

Finally, exterior upgrades can protect vulnerable lower wall areas and refresh curb appeal. Wainscot systems, entry enhancements and updated finishes help older buildings better reflect current branding or prepare them for resale. Together, these improvements can significantly extend a building’s useful life and reposition it as a durable, code-compliant asset. 

Learn more about how strategic retrofits can unlock the full potential of older metal buildings!

By Jesse Sanchez. 

Industry engineers say single-ply systems perform best when contractors understand water flow and structural loading impacts. 

The growing use of single-ply membranes to re-cover existing metal roofs has become common across the industry and companies such as Roof Hugger, alongside Force Engineering and Testing Inc., have spent years studying why the approach can introduce hidden structural risk. Fast installation, warranty options and relatively low upfront cost have made single-ply systems attractive, but engineers say the method changes how metal buildings manage water and heavy loads in ways they were never designed to handle. 

According to research published in RCI Interface, pre-engineered metal buildings rely on purlins that are designed for balanced loading across each bay. When a ribbed metal roof is in place, water flows between panel ribs and drains evenly, keeping loads confined. A single-ply membrane removes those channels. Water instead migrates toward mid-span deflection points, concentrating weight where purlins are already designed to flex. Over time, that concentration can worsen existing dips or create new ones, pulling water from adjacent bays and compounding stress across the structure.  

There are several scenarios where that redistribution becomes dangerous, including overloaded or damaged purlins, dips near the eave strut and sudden lateral water movement caused by billowing under wind loads. In one documented case involving an internally drained standing seam roof, localized ponding escalated rapidly as water was drawn into a single bay. As one purlin deflects, adjacent bays can rise, diverting even more water into the weakened area until collapse occurs.  

Testing conducted by engineers illustrates how narrow the margin can be. In a base test using typical low-slope metal building components, purlins buckled at 23.9 pounds per square foot. One inch of water weighs 5.2 pounds per square foot, meaning failure occurred with roughly 4.6 inches of accumulated water. The findings make it easy to see how altered drainage paths can push systems beyond their limits during heavy storms.  

It is important to note that re-covering metal roofs is not inherently flawed. There are many valid reasons to re-cover an existing metal building roof that is not performing optimally, but the experts stress that success depends on eliminating the underlying causes of failure rather than covering them over. Their conclusion is clear that the most effective way to recover an existing metal roof on a metal building is to install another metal roof. 

For contractors, the takeaway is not to abandon retrofits but to understand how system choice interacts with structure. Symmetrical standing seam metal-over-metal systems, the authors argue, maintain balanced loading, improve wind performance and allow future repairs without compromising the building’s original design intent.  

Learn more about the engineering considerations behind metal roof re-cover decisions and how system selection affects long-term performance!

By Jesse Sanchez. 

Rising demand for durable, energy-efficient roofing drives self storage owners toward retrofits. 

Aging metal roofs across the self storage sector are prompting a reassessment of how owners manage building longevity. Where owners once defaulted to full roof replacements as the solution, the demand is now shifting toward retrofit systems that reinforce structure while creating room for energy improvements and long-term operating gains. The shift reflects a more pragmatic outlook among operators who want durability without shutting down business. Roof Hugger has become central to this discussion. Many owners begin with the assumption that a tear off is unavoidable, yet Roof Hugger notes that “there’s a simpler, safer way of getting the job done without disrupting daily operation.” That line carries weight in an industry where interruptions are costly, and tenant access is nonnegotiable. Retrofitting presents a solution that keeps facilities operational while addressing structural needs. 

In a retrofit project, structural steel sub framing is fastened through the existing roof, allowing the new panels to meet all current wind and snow load code requirements. The approach effectively modernizes performance without discarding a functional base. This combination of reinforcement and continuity makes retrofits compelling to building owners. Even better, not only do they remedy failure, but also open opportunities to improve the building in ways replacement alone cannot. 

One example of other changes seen in the self storage sector is the shift from older screw down or through fastened roofs to standing seam systems. With fewer exposed fasteners, these assemblies offer better durability and cleaner installation. The airspace created between old and new panels supports insulation upgrades, making climate-controlled conversions more feasible and above sheathing ventilation can reduce heat transfer by as much as 45%. For operators, that means lower energy load and better comfort in non-conditioned units. Solar ready standing seam roofs add another layer of value, offering secure panel attachment without penetrations. 

Taken together, these advantages signal why retrofits are gaining traction among self storage building owners who want stronger buildings without sacrificing uptime. The combination of structural reinforcement, energy potential and long service life gives operators a practical path to improve performance while controlling costs. As systems evolve and incentives continue to favor upgrades over replacement, retrofits are likely to play a larger role in how facilities plan for the future.  

Learn more about how retrofit framing can strengthen your next roofing project!