Roof System Selection for Aramco Stadium

To view the figures and tables associated with this article, please refer to the flipbook above.

Large-span stadium structures require envelope systems that balance structural efficiency, durability, thermal performance, and constructability. Among the most widely adopted solutions are standing-seam metal roofing systems and insulated sandwich panel systems, each offering distinct advantages for complex geometries and high-performance building envelopes. Both systems are evaluated here within the context of the Aramco Stadium project in Khobar, Saudi Arabia, highlighting performance criteria that influenced the adoption of an aluminum standing-seam roof rather than the originally specified sandwich panel, focusing on mechanical performance, weatherproofing characteristics, thermal efficiency, and installation methodology. Through a technical comparison, this study identifies the key parameters that influence system selection in modern stadium developments. The findings contribute to a deeper understanding of roofing system behavior in high-demand sports infrastructure and provide a framework for informed material selection in stadium design.

Roofing systems used in large-span structures pose a distinct set of technical challenges driven by their scale, exposure conditions, and structural behavior. Large roof surfaces are subjected to significant wind effects and temperature-induced movement, while the supporting structural systems experience accumulated deflections that must be accommodated without compromising envelope performance. Simultaneously, contemporary roof architecture increasingly adopts complex and non-linear geometries, imposing additional demands on cladding systems with regard to flexibility, constructability and tolerance.

Within this framework, the roofing system fulfills a critical role as both the protective envelope and the interface with the load-bearing structure. The selected system must provide weather tightness and durability while accommodating structural movement, thermal effects and service-life demands. Metal roofing systems are therefore widely adopted in large-span applications due to their strength-to-weight ratio, durability and flexibility.

Among metal roofing solutions, standing-seam metal roofing systems and insulated sandwich panel systems represent two distinct approaches to roof construction. Each system is governed by design and performance principles influencing load transfer, thermal movement, constructability and lifecycle performance. A thorough understanding of these system behaviors is crucial for informed system selection in large-span roof design.

The original roof skin design is composed of insulated metal sandwich panels fixed to the secondary steel structure. The system, as illustrated by Figure 1, comprises top and bottom sheets bonded to an integrated insulation core, forming a composite panel that simultaneously offers environmental protection, thermal insulation and acoustic performance.

The panels are mechanically fixed to the secondary steel members using manufacturer-approved fasteners. This configuration allows the transfer of dead, live, and environmental loads to the supporting steel structure while ensuring stability of the overall system. Weather tightness is provided by the profiled overlaps and sealed joints, with the external sheet acting as the primary weather-resistant layer.

Thermal performance is achieved through the continuous insulation layer, limiting heat transfer through the roof and reducing solar heat gain within the stadium. The composite panel configuration additionally contributes to acoustic attenuation, supporting internal comfort requirements. Factory fabrication of the panels under controlled conditions ensures material properties and performance are consistent throughout the stadium roof.

While the system offers an efficient construction solution and integrated performance, the reliance on through-fixings and panel joints requires careful detailing to address thermal expansion and structural deflection. In large-span roof structures, this must be accommodated through appropriate panel sizing, joint configuration, and fixing layouts to prevent degradation of weather-tightness and to perform as intended over its design life.

Standing-seam metal roofing systems consist of continuous metal sheets joined along raised interlocking seams specifically engineered for large scale and complex roof geometries. The top metal sheet, typically using aluminum or steel material, is roll-formed on site to the desired length extending up to 100 meters, minimizing number of joints exposed to water ingress and reducing risk of long-term leakage while improving durability. Cold bending of the sheets allows curvature down to a 4,000 mm radius, making it highly adaptable to Aramco Stadium’s elliptical form.

Structural performance of the system is achieved through the continuous seams and concealed clips that secure the sheets to the secondary steel members without penetrating the outer skin, eliminating fastener leakage risks common in conventional sandwich panel systems. These clips are designed to allow for temperature-induced movement of the sheets, preventing stress concentrations. Adjacent top sheets are joined by snap-locked seams, creating a continuous watertight connection eliminating need for visible through-fixings. Testing in accordance with EN 14782, ASTM E1646 (watertightness), and ASTM E283 (air permeability) standards verified system reliability under extreme weather conditions.

Acoustic performance is enhanced through integration of perforated liner trays and mineral wool insulation, achieving weighted sound reduction index (Rw) ratings up to 45 depending on configuration. Installation logistics are optimized by lightweight aluminum components, reducing structural load demands on the secondary steel. Notable international projects employing standing-seam includes the Allianz Arena (Germany), Wembley Stadium (United Kingdom), and Hamad International Airport (Qatar), confirming its suitability for global landmark structures.
To achieve the structural and acoustic requirements of the Aramco Stadium project, three specially designed build-ups were proposed (Fig. 2).

The build-up located at the innermost portion of the roof where acoustic performance is not mandatory features a non-perforated linear tray as the bottom layer (Fig. 3). The top layer of the system is an aluminum sheet roll-formed on site and the layers in-between are filled with layers of fiber insulation as denoted by numbers (3) and (6) on Figure 3 and LPDE membrane sandwiched between to provide for the watertightness and moisture control. The total weight of the system here is 4.4 pounds/square foot (21.49 kilogram/square meter), with an acoustic rating of Rw 41 and U-value of 0.20 W/m2.K.

The buildup in Figure 5 is located at the middle portion of the roof, where acoustic performance is required. The build-up for this section is similar to the non-acoustic liner tray system, however the bottom liner tray fixed to the secondary steel is perforated as indicated by number (7) on Figure 5. The perforations reduce the sound wave reflections, allowing the sound waves to travel into the insulation layers of the build-up. This improves sound absorption thereby increasing the acoustic performance of the roof. The total weight of the system here is 20.69 kg/m2, with a slightly higher acoustic rating of Rw 43 and U-value of 0.20 W/m2.K.

For the last system build-up at the lowest part, the system features a structural decking as the base layer, ideal for larger spans and better structural performance (Fig. 7). The total weight of the system here is 5.08 pounds/square foot (24.81 kilograms/square meter), with an acoustic rating of Rw 43 and U-value of 0.25 W/m2.K.

Case studies offer valuable insight on the performance of metal roofing system solutions under similar large-span envelopes and challenging climates.

The Hazza Bin Zayed Stadium in Al Ain has been widely referenced in studies evaluating the long-term behavior of sandwich panel system assemblies exposed to high temperatures, especially within the Gulf region with multiple recent stadium projects. Post-completion observations noted repeated thermal movement within the roof structure, resulting from prolonged exposure to high solar radiation and significant diurnal temperature fluctuations. Over time, the differential expansion between the metal facings and the insulation core contributed to deterioration of the panel joints and sealant interfaces. While initial performance requirements were met by the system, its long-term behavior revealed limitations in accommodating sustained thermal stresses typical in the Gulf region.

By comparison, stadiums such as the Allianz Arena in Munich utilizing a standing-seam aluminum system demonstrated more favorable long-term behavior under similar performance requirements. The system was specially engineered to accommodate thermal movement without inducing significant internal stress through continuous panels and concealed sliding clips. Long-term service data highlight maintained structural integrity, weather tightness and minimal maintenance intervention. The system’s ability to accommodate movement while preserving envelope integrity has been widely identified as a key advantage in large-span roof applications. These findings collectively support the selection of standing-seam roofing rather than conventional sandwich panel assemblies for projects such as Aramco Stadium, where long-term durability and controlled structural behavior are critical design considerations.

Standing-seam roofing systems accommodate structural and thermal movement through concealed sliding clips that allow controlled metal panel displacement while resisting wind uplift forces. This design mitigates stress concentrations and enhances system reliability under cyclic thermal loading and structural deflection conditions. This is particularly critical in large-span roofs where thermal expansion and structural deflection can be substantial.

In contrast, sandwich panel systems rely on mechanical fixings and joint-detailing to manage movement. While this approach provides sufficient structural stability, it offers less tolerance for deflection. In large-span roofs, restrained movement can lead to increased stress concentrations, leading to connection fatigue resulting in joint distress or local deformation if not carefully considered during design.

Standing-seam roofing systems are formed to suit varying radii, facilitating installation across complex roof geometries, especially found in stadiums, and ensuring adaptability to support non-planar roof geometries. The system’s top metal sheet is roll-formed on-site to support architectural vision while ensuring a seamless surface.

Sandwich panel systems, by contrast, support the stadium’s construction goals as part of an accelerated project, benefiting from the prefabrication of the system. However, the inherent stiffness of sandwich panels accommodating only flat or single-curved geometries limits its suitability for curved roof designs, requiring additional detailing to achieve the final shape.

Thermal performance in standing-seam systems is governed by several insulation layers installed within the roof assembly, allowing more flexible choosing of the insulation type and thickness. However, this must also involve careful coordination to ensure thermal performance across the roof meets requirements and performs as intended.

Sandwich panels, in contrast, rely on the insulation core to achieve desired thermal performance under factory-controlled conditions. This approach simplifies thermal design and reduces risk of thermal-bridging during construction.

The weather performance of standing-seam systems is achieved through the seamless design and concealed fixings of the system forming a continuous skin and reducing the number of exposed joints. This design ensures limited exposure to water, being tested for watertightness under simulated wind-driven rain at pressures exceeding 1,200 Pa, ensuring long-term weather resistance and durability.

Performance of sandwich panel systems heavily relies on joint performance and mechanical fixings of the panels. Over time, thermal cycling may degrade the joints and lead to micro-leakage. Field data from other stadiums within the region highlight similar issues, requiring frequent maintenance.

Acoustic requirements differ depending on building type and occupancy. The standing-seam build-up components are carefully chosen to meet those requirements. For the middle section of the Aramco Stadium roof where acoustic requirements apply, the bottom metal sheets are perforated allowing sound waves from inside the bowl to travel into the insulation layers. Acoustic rating of this assembly, validated through stadium mock-up tests is Rw 43-45 dB, complying with FIFA facade acoustic requirements and demonstrating increased spectator comfort.

Sandwich panel systems generally provide lower acoustic insulation levels, with laboratory test findings expressing Rw values between 30-32 dB, sufficient for industrial and commercial buildings. This requires further measures for sound attenuation within the roof envelope.

The long-term performance of the standing-seam system is typically higher than other metal roofing solutions due to their corrosion resistance and maintenance ease. Case studies including the Allianz Arena and Wembley Stadium document lifespans of 40-60 years. The specialized modular design of the system further allows localized replacement reducing maintenance disruption.

Sandwich panels, in contrast, degrade after 20-25 years due to environmental exposure and joint durability. Maintenance of panels disrupts the surrounding area, as adjacent panel removal is typically required for replacement.

Sustainability considerations were critical in the adoption of an aluminum standing-seam system rather than the originally specified sandwich panel system. The top and bottom metal sheets of the system are aluminum, a fully recyclable material without loss of intrinsic properties, facilitating closed-loop material cycle and circular economy objectives. By comparison, the metal facings of sandwich panels are bonded with the insulation cores, complicating end-of-life separation resulting in higher energy recycling process or increased landfill waste.

The lightweight nature of the aluminum panels also contributes to structural efficiency. The reduced deadload decreases demand on the supporting steel structure, reducing embodied carbon through decreased steel tonnage. Lifecycle assessment studies show that aluminum roofing systems can achieve up to 30-40% lower embodied energy relative to conventional composite systems. These performance characteristics align with sustainability objectives of Saudi Vision 2030 as well as global certification frameworks such as LEED V4 and BREEAM. Additionally, the demountable nature of the system allows for potential reuse in future applications, further reducing lifecycle environmental impact. ■

About the Authors

Padraic Leonard is a seasoned project management professional with approximately 21 years of international experience. Currently serving as a Supervisor for the Aramco Stadium Project, he played the pivotal role in leading the delivery of the stadium’s concrete structure, structural steel, and the stadiums complex facade including iconic petal roof.

Sultanh Algethami was a project engineer supporting the roofing facade works. She holds a bachelor’s degree in civil engineering from the University of Manchester.

Khaled Almohaisen was the lead project engineer overseeing the internal and roofing facades of Aramco Stadium. Almohaisen has contributed to major capital projects across the Kingdom, including King Salman Energy Park (SPARK) and the King Salman International Complex for Maritime Industries and Services.