Photo by Yajaida Pacheco; courtesy of ALPOLIC
Metal Composite Material (MCM) is revolutionizing the possibilities of building envelope design as a durable, lightweight, and exceptionally versatile product.
“Design, by definition, is an eco-friendly activity, as its aim is to create objects which are meaningful and durable. Trends always cost resources, but a true designer creates wares which will remain relevant forever.”
— Marcel Wanders, Dutch Industrial and Interior Designer
What is MCM?
Arriving on the scene over 50 years ago as aluminum composite material (ACM), today’s metal composite material (MCM) has evolved in both composition and name, reflecting the inclusion of other natural metal skins such as zinc, copper, stainless steel, and titanium. Aluminum remains the predominant MCM skin material, acting as a durable palette for a broad spectrum of coil-coated colors.
The International Building Code® (IBC) defines MCM as metal skins bonded to both sides of a solid plastic core. This composition makes MCM lightweight, durable, and visually striking. Bottom metal skins receive a protective surface treatment while top skins can be coil-coated with primer, a color coat, and, in some cases, a clear coat to preserve the organic metal appearance. Performance standards for this coating are often not required on the bottom surface, as it is hidden. The plastic core type of an MCM is a critical consideration. A standard core of polyethylene is acceptable for low-rise applications. However, a fire-resistive core is needed to satisfy requirements as a fire-retardant material, where required. This fire-resistive core includes additives or inert fillers to meet the performance requirements that the National Fire Protection Association® (NFPA) 285 mandates for mid- or high-rise buildings. The primary goal of NFPA 285 testing is to ensure that exterior wall assemblies are safe and will not contribute to rapid fire spread in a multi-story building. MCM products have over 30 years of proven performance in meeting stringent safety codes.
Image courtesy of the Metal Construction Association’s Metal Composite Material Alliance
Cutaway of an MCM panel.
MCM is a popular product in commercial design. It is a high-tech material that provides a modern image and offers design versatility through alternative surface textures, shapes, and appearances. Because MCM delivers a tested and proven cladding assembly, architects can feel confident that code and performance goals are met. MCM is also growing in popularity for single- and custom-family homes, both in broad exterior applications or for fascia, soffits, and accents. The proven fire-resistance of MCM offers peace of mind for homeowners. Though not currently covered by code, the expansion of fire-resistive cores will continue, including for low-rise structures.
Exploring MCM Design Flexibility
MCM is an elite metal construction product. Manufacturer quality control ensures the sheet is smooth and flat, and fabricator-engineered systems retain this flatness through installation. No “oil canning” or aesthetic failures due to poor bonding technology plague MCM. MCM panels are produced with heat, pressure, and tension, creating a well-balanced and well-bonded sheet.
Design flexibility and modern material performance are twin virtues of MCM products. As MCM is produced under precise conditions in the factory and fabricated with the expertise of a fabricator in shop, many high-concept features can be specified. The properties of MCM as a material enable the special customization of a fabricator, allowing for “high concept” features to be implemented. MCM not only provides consistent flatness, but also consistency with coil-coated finishes. Aluminum MCM can be finished in a broad spectrum of colors, meeting the owners’ and architects’ desired look or required tones. The finished product is easy to maintain—cleaning involves a freshwater rinse. This is recommended once a year, or when windows are cleaned. Where natural metal is desired, MCM can provide a variety of alternative skins, including zinc, copper, stainless steel, and titanium. These natural materials can shine in design.
Photo courtesy of 3A Composites
MCM provides a tested and proven system that encourages imaginative design through material versatility.
Though smooth finishes and crisp lines are a standard hallmark of the product, MCM can also be rolled, folded, and bent into dynamic shapes or rounded into a custom radius. Curtain walls that are light, adaptable, and sustainable lend a signature look with MCM artistic elements incorporated and offer a proven solution to facade management challenges. Wall panels designed with MCM easily create visual interest and offer functionality that does not limit design intent. These panels are also available in “cool colors” that inhibit heat and provide energy savings by offsetting solar heat gain. Custom sunshades, louvers, prismatic and trapezoidal panels, lighting supports, soffits, and sculptural installations are all possibilities, where MCM combines aesthetics with performance. MCM, detailed with a timber finish, mimics realistic woodgrains without the weight or maintenance concerns of real wood. Canopies and corporate identities are also easily captured and displayed by MCM products. The consistent color quality of MCM ensures standardization for recognizable brands.
Using MCM to add architectural elements transforms a building into an architectural destination. Design technology advancements allow sculptural elements that both integrate with and transform a design, creating dimension while also bringing the performance and sustainability of MCM to the exterior.
As an interior design element, MCM offers the same flexibility and durability, showcasing unique designs, supporting lighting, and providing enduring visual interest to the interior. Interior artistic elements can also provide an added layer of practicality: specified MCM can deliver acoustical control. Examples include acoustic management in theaters, concert halls, and airport interiors. MCM can also integrate around the lighting and fire suppression systems, providing a beautiful surrounding for critical systems. Collaboration between acoustical engineers, architects, manufacturers, and fabricators brings a streamlined, multi-purpose, and beautiful design to a project.
MCM Planning and Installation Considerations
Because of product attributes, MCM offers a streamlined choice to meet the growing body of code requirements designers face, including safety, fire, sustainability, performance, and building health.
Guaranteeing Performance: Code Requirements and MCM
Placing a product on a building means betting the future of the structure on that product’s performance over time. MCM panels are subject to IBC Chapter 14 requirements, including weather resistance (Water Resistance – ASTM E331; Air Infiltration – ASTM E283) and mandated uses of flashing and weather-resistant barriers (WRBs). Structurally, MCM designs must comply with IBC Chapter 16, with assessments governed by ASTM E330 (Structural Performance) and rainscreen assessments conducted under AAMA 508 or 509. Performing under these tests demonstrates that MCM products will act as approved assembly components for the project’s lifetime.
As a metal composite material, MCM panels are also governed by Chapter 14, NFPA 285 Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components. Preventing fire and keeping any fire damage to a minimum is a primary industry and regulatory concern. U.S. codes require that a fire test incorporate every one of the components of the wall assembly, exactly as the product is to be installed and used in the field, instead of testing individual components separately. MCM containing a fire retardant (FR) core material exhibits excellent fire performance, including no poisonous off-gassing. NFPA 285 is required for wall assemblies containing combustible components and applies to Construction Types I, II, III, and IV. To pass the test, all assembly components, including thermal barriers, vapor barriers, insulation, attachment materials and methods, and any combustible components, are tested together as an assembly. Different requirements are mandatory, depending on Construction Type I, II, III, IV, or V. IBC Section 705 provides requirements for Fire Ratings of Exterior Walls, including an ASTM E119 fire-resistance rating. ASTM E119 is the standard for testing the fire resistance of building construction materials and assemblies, and measures how long an assembly can resist fire exposure without the transmission of sufficient heat or hot gases and without loss of structural integrity under a prescribed load. As a note for designers, if fasteners do not penetrate the entire wall, and MCM acts as a cladding over a wall, it does not necessarily need to be tested to ASTM E119. Additionally, ASTM E84 (UL 723) is used to assess flame spread and smoke developed MCM’s surface burning characteristics. A material with an ASTM E84 Class A rating has a flame spread index less than or equal to 25 and a smoke developed index less than or equal to 450.
Image courtesy of the Metal Construction Association’s Metal Composite Material Alliance
As a metal composite material, MCM panels are also governed by Chapter 14, NFPA 285 Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components. This chart offers an overview of when to apply NFPA to the product.
Where accepted by local code officials and permitted by IBC Section 104.11, engineering evaluations offer another viable path for evaluating assemblies. An engineering evaluation addresses proposed variations and substitutions of building construction materials in wall cladding assemblies. They are based on engineering data from successful NFPA 285 tests and are developed on a case-by-case basis. The evaluation must be completed by a qualified, experienced technical organization, consultant, or engineer, and must clearly describe the change being requested and how it varies from the successful NFPA 285 tested assembly. The engineering evaluation must provide technical justification for the proposed change and demonstrate how the substitution or change will be found acceptable, whether through additional testing, technical data and rationale, or historic testing data. Ultimately, the variation or substitution must provide the wall assembly with the same or similar fire performance as the assembly referenced from NFPA 285 testing. Finally, it is important to note that not every design change can or will be accepted by the authority having jurisdiction, supported with an engineering evaluation.
MCM product labeling requirements are also governed by code. IBC 1406.14 mandates that all MCM panels be tested, inspected, and labeled. IBC 1703.5, 1703.4.1 through 1703.5.4, sets those requirements. The MCM product must be tested and assessed through an approved third-party agency with tests relevant to IBC Code Test Standards. The manufacturer must maintain a record of production and internal quality testing performed with sufficient detail to verify compliance with test standards by a third-party laboratory or other means accepted by the code agency, which will conduct periodic in-plant inspections to ensure that an MCM product’s input materials match those used for the performance testing. An efficient way to confirm if an MCM product has been tested and verified as compliant is through Product Listing and Code Compliance reports, available from organizations such as the International Code Council® (ICC) Evaluation Service (ES) and Intertek®.
When an MCM product is verified to have met required testing, certifications, and is compliant with building codes, the design team can be confident that the entire assembly has been scrutinized with a critical eye. Everything from the metal skins’ thickness, tensile and yield properties, to the fire-resistant composite core’s properties, including cohesion and adhesion (how well the core sticks to metal skins), is evaluated. This extends to panel design and encompasses interlock depth, joint strength, distance between side joints, thickness, and finally, attachment methods performance under structural tests such as ASTM E330, as well as specific analysis of attachment clips and fasteners with their corresponding performance data.
Photo by Yajaida Pacheco; courtesy of ALPOLIC
Metal Composite Material (MCM) is revolutionizing the possibilities of building envelope design as a durable, lightweight, and exceptionally versatile product.
“Design, by definition, is an eco-friendly activity, as its aim is to create objects which are meaningful and durable. Trends always cost resources, but a true designer creates wares which will remain relevant forever.”
— Marcel Wanders, Dutch Industrial and Interior Designer
What is MCM?
Arriving on the scene over 50 years ago as aluminum composite material (ACM), today’s metal composite material (MCM) has evolved in both composition and name, reflecting the inclusion of other natural metal skins such as zinc, copper, stainless steel, and titanium. Aluminum remains the predominant MCM skin material, acting as a durable palette for a broad spectrum of coil-coated colors.
The International Building Code® (IBC) defines MCM as metal skins bonded to both sides of a solid plastic core. This composition makes MCM lightweight, durable, and visually striking. Bottom metal skins receive a protective surface treatment while top skins can be coil-coated with primer, a color coat, and, in some cases, a clear coat to preserve the organic metal appearance. Performance standards for this coating are often not required on the bottom surface, as it is hidden. The plastic core type of an MCM is a critical consideration. A standard core of polyethylene is acceptable for low-rise applications. However, a fire-resistive core is needed to satisfy requirements as a fire-retardant material, where required. This fire-resistive core includes additives or inert fillers to meet the performance requirements that the National Fire Protection Association® (NFPA) 285 mandates for mid- or high-rise buildings. The primary goal of NFPA 285 testing is to ensure that exterior wall assemblies are safe and will not contribute to rapid fire spread in a multi-story building. MCM products have over 30 years of proven performance in meeting stringent safety codes.
Image courtesy of the Metal Construction Association’s Metal Composite Material Alliance
Cutaway of an MCM panel.
MCM is a popular product in commercial design. It is a high-tech material that provides a modern image and offers design versatility through alternative surface textures, shapes, and appearances. Because MCM delivers a tested and proven cladding assembly, architects can feel confident that code and performance goals are met. MCM is also growing in popularity for single- and custom-family homes, both in broad exterior applications or for fascia, soffits, and accents. The proven fire-resistance of MCM offers peace of mind for homeowners. Though not currently covered by code, the expansion of fire-resistive cores will continue, including for low-rise structures.
Exploring MCM Design Flexibility
MCM is an elite metal construction product. Manufacturer quality control ensures the sheet is smooth and flat, and fabricator-engineered systems retain this flatness through installation. No “oil canning” or aesthetic failures due to poor bonding technology plague MCM. MCM panels are produced with heat, pressure, and tension, creating a well-balanced and well-bonded sheet.
Design flexibility and modern material performance are twin virtues of MCM products. As MCM is produced under precise conditions in the factory and fabricated with the expertise of a fabricator in shop, many high-concept features can be specified. The properties of MCM as a material enable the special customization of a fabricator, allowing for “high concept” features to be implemented. MCM not only provides consistent flatness, but also consistency with coil-coated finishes. Aluminum MCM can be finished in a broad spectrum of colors, meeting the owners’ and architects’ desired look or required tones. The finished product is easy to maintain—cleaning involves a freshwater rinse. This is recommended once a year, or when windows are cleaned. Where natural metal is desired, MCM can provide a variety of alternative skins, including zinc, copper, stainless steel, and titanium. These natural materials can shine in design.
Photo courtesy of 3A Composites
MCM provides a tested and proven system that encourages imaginative design through material versatility.
Though smooth finishes and crisp lines are a standard hallmark of the product, MCM can also be rolled, folded, and bent into dynamic shapes or rounded into a custom radius. Curtain walls that are light, adaptable, and sustainable lend a signature look with MCM artistic elements incorporated and offer a proven solution to facade management challenges. Wall panels designed with MCM easily create visual interest and offer functionality that does not limit design intent. These panels are also available in “cool colors” that inhibit heat and provide energy savings by offsetting solar heat gain. Custom sunshades, louvers, prismatic and trapezoidal panels, lighting supports, soffits, and sculptural installations are all possibilities, where MCM combines aesthetics with performance. MCM, detailed with a timber finish, mimics realistic woodgrains without the weight or maintenance concerns of real wood. Canopies and corporate identities are also easily captured and displayed by MCM products. The consistent color quality of MCM ensures standardization for recognizable brands.
Using MCM to add architectural elements transforms a building into an architectural destination. Design technology advancements allow sculptural elements that both integrate with and transform a design, creating dimension while also bringing the performance and sustainability of MCM to the exterior.
As an interior design element, MCM offers the same flexibility and durability, showcasing unique designs, supporting lighting, and providing enduring visual interest to the interior. Interior artistic elements can also provide an added layer of practicality: specified MCM can deliver acoustical control. Examples include acoustic management in theaters, concert halls, and airport interiors. MCM can also integrate around the lighting and fire suppression systems, providing a beautiful surrounding for critical systems. Collaboration between acoustical engineers, architects, manufacturers, and fabricators brings a streamlined, multi-purpose, and beautiful design to a project.
MCM Planning and Installation Considerations
Because of product attributes, MCM offers a streamlined choice to meet the growing body of code requirements designers face, including safety, fire, sustainability, performance, and building health.
Guaranteeing Performance: Code Requirements and MCM
Placing a product on a building means betting the future of the structure on that product’s performance over time. MCM panels are subject to IBC Chapter 14 requirements, including weather resistance (Water Resistance – ASTM E331; Air Infiltration – ASTM E283) and mandated uses of flashing and weather-resistant barriers (WRBs). Structurally, MCM designs must comply with IBC Chapter 16, with assessments governed by ASTM E330 (Structural Performance) and rainscreen assessments conducted under AAMA 508 or 509. Performing under these tests demonstrates that MCM products will act as approved assembly components for the project’s lifetime.
As a metal composite material, MCM panels are also governed by Chapter 14, NFPA 285 Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components. Preventing fire and keeping any fire damage to a minimum is a primary industry and regulatory concern. U.S. codes require that a fire test incorporate every one of the components of the wall assembly, exactly as the product is to be installed and used in the field, instead of testing individual components separately. MCM containing a fire retardant (FR) core material exhibits excellent fire performance, including no poisonous off-gassing. NFPA 285 is required for wall assemblies containing combustible components and applies to Construction Types I, II, III, and IV. To pass the test, all assembly components, including thermal barriers, vapor barriers, insulation, attachment materials and methods, and any combustible components, are tested together as an assembly. Different requirements are mandatory, depending on Construction Type I, II, III, IV, or V. IBC Section 705 provides requirements for Fire Ratings of Exterior Walls, including an ASTM E119 fire-resistance rating. ASTM E119 is the standard for testing the fire resistance of building construction materials and assemblies, and measures how long an assembly can resist fire exposure without the transmission of sufficient heat or hot gases and without loss of structural integrity under a prescribed load. As a note for designers, if fasteners do not penetrate the entire wall, and MCM acts as a cladding over a wall, it does not necessarily need to be tested to ASTM E119. Additionally, ASTM E84 (UL 723) is used to assess flame spread and smoke developed MCM’s surface burning characteristics. A material with an ASTM E84 Class A rating has a flame spread index less than or equal to 25 and a smoke developed index less than or equal to 450.
Image courtesy of the Metal Construction Association’s Metal Composite Material Alliance
As a metal composite material, MCM panels are also governed by Chapter 14, NFPA 285 Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components. This chart offers an overview of when to apply NFPA to the product.
Where accepted by local code officials and permitted by IBC Section 104.11, engineering evaluations offer another viable path for evaluating assemblies. An engineering evaluation addresses proposed variations and substitutions of building construction materials in wall cladding assemblies. They are based on engineering data from successful NFPA 285 tests and are developed on a case-by-case basis. The evaluation must be completed by a qualified, experienced technical organization, consultant, or engineer, and must clearly describe the change being requested and how it varies from the successful NFPA 285 tested assembly. The engineering evaluation must provide technical justification for the proposed change and demonstrate how the substitution or change will be found acceptable, whether through additional testing, technical data and rationale, or historic testing data. Ultimately, the variation or substitution must provide the wall assembly with the same or similar fire performance as the assembly referenced from NFPA 285 testing. Finally, it is important to note that not every design change can or will be accepted by the authority having jurisdiction, supported with an engineering evaluation.
MCM product labeling requirements are also governed by code. IBC 1406.14 mandates that all MCM panels be tested, inspected, and labeled. IBC 1703.5, 1703.4.1 through 1703.5.4, sets those requirements. The MCM product must be tested and assessed through an approved third-party agency with tests relevant to IBC Code Test Standards. The manufacturer must maintain a record of production and internal quality testing performed with sufficient detail to verify compliance with test standards by a third-party laboratory or other means accepted by the code agency, which will conduct periodic in-plant inspections to ensure that an MCM product’s input materials match those used for the performance testing. An efficient way to confirm if an MCM product has been tested and verified as compliant is through Product Listing and Code Compliance reports, available from organizations such as the International Code Council® (ICC) Evaluation Service (ES) and Intertek®.
When an MCM product is verified to have met required testing, certifications, and is compliant with building codes, the design team can be confident that the entire assembly has been scrutinized with a critical eye. Everything from the metal skins’ thickness, tensile and yield properties, to the fire-resistant composite core’s properties, including cohesion and adhesion (how well the core sticks to metal skins), is evaluated. This extends to panel design and encompasses interlock depth, joint strength, distance between side joints, thickness, and finally, attachment methods performance under structural tests such as ASTM E330, as well as specific analysis of attachment clips and fasteners with their corresponding performance data.
MCM and Performance Over Time
Photo courtesy of Miller Clapperton
Properly designed, tested, and installed MCM systems provide a very reliable building envelope that endures. Vanderbilt Basketball practice facility.
It is important that products not only demonstrate compliance during testing but that they maintain this performance over time. This has ramifications not only for safety and welfare, but also for the longevity and costs of a project. Environmental factors influence cladding degradation, and the age of the facade material influences that degradation. Over time, claddings are subjected to the cumulative action of degradation agents. The greater the age and the longer the exposure period of the cladding equates to more severe expected degradation, in the absence of maintenance actions.1
Durability is a trait often detrimentally excluded during value engineering. Value engineering should aim to achieve the essential functions of the design at the lowest life cycle cost, consistent with the required performance. For cladding, a material must provide the “5 D’s”: deflection, draining, drying, durability, and design. To achieve durability, the calculated costs must anticipate not only installed cost but also the incurred costs over time from repair, maintenance, and disposal.
Historically, MCM systems were limited to high-end projects due to cost. As manufacturers have advanced product technology, improved fabricator efficiencies, and varieties of new installation techniques make today’s MCM cost competitive. Initial construction costs are often lower with MCM systems because panels can typically be installed faster than alternative exterior products, such as precast, granite, or brick. Lightweight MCM systems can also save money by reducing structural steel requirements, since less structural support is needed.
With MCM, ongoing maintenance costs are reduced. Today’s MCM panels retain their luster for decades, ensuring that the building maintains its aesthetic appeal and its property value for the long term. Maintenance only requires an annual freshwater rinse. This longevity makes a difference when it comes time to sell the building. Facilities clad with high-tech MCM systems retain their curb appeal and never look dated, often reducing the need for refurbishing. MCM also facilitates easy renovations and building enhancements. The panels are flexible and can adapt to structural retrofits, accommodating new layouts or additions. MCM panels can also be easily disassembled for reuse.
MCM Finishes
Photo courtesy of Abrams Architectural Products
Aluminum MCM can be finished in a broad spectrum of colors to satisfy any desired look. Savoy Automobile Museum.
The most commonly used metal substrate for MCM skins is aluminum. Custom panels can be made from other natural metals, like stainless steel, zinc, or copper or titanium, providing the beauty of genuine metal materials at a fraction of the weight and cost of traditional solid metal panels.
MCM provides long-lasting, durable finishes generated in a controlled environment. MCM is offered in a variety of high-performance coatings, with MCM panels having finish warranties of up to thirty years. PVDF (Kynar), FEVE (Fluoropolymer-based), SMP (silicone modified polyester), and Polyester are available. Standard 1.0 mil and high build systems offer different finishes, including mica, metallic, weathered metal, wood grain, and prismatic. Long-lasting, low-maintenance paint finishes in a multitude of colors provide the ultimate in design flexibility and longevity.
Finishes from leading MCM manufacturers adhere to the voluntary performance standards of AAMA®, the American Architectural Manufacturers Association. The standards in AAMA 2605-20 cover test procedures and performance requirements for organic coatings applied in the factory. Factory-applied coats with superior performance demonstrate film integrity, exterior weatherability, and sustained appearance over time. AAMA 2605 specifically evaluates 70 percent PVDF, HD Polyester, and FEVE formulations. Compliant finishes exhibit abrasion resistance, color retention, gloss retention, corrosion resistance, chalking resistance, and erosion resistance.
Resilience and Sustainability
Photo by Bob Perzel Photography; courtesy of Reynobond
MCM is not only a durable and beautiful product, but it is also an environmentally responsible and sustainable choice for today’s buildings. Boston University Data Center.
Properly designed, tested, and installed MCM systems provide a reliable and approved building envelope that resists the elements and protects against air and water infiltration. The best MCM products also provide durability, longevity, and sustainability.
Quality MCM is remarkable for its ability to maintain shape. Manufacturer quality controls ensure that MCM sheets are flat, and fabricator-engineered systems retain that flatness through installation. MCM sheets are trimmed, squared, and come with a protective film that safeguards the finish and provides directional arrows, where needed, to assist in clear and proper installation in the field. The panels exhibit no oil canning once installed. The balanced skins on both sides of the MCM prevent the distortion common to traditional sheet metal installations.
MCM panels retain their color and finish for decades. Additionally, the luster of the panel does not fade. Since metal is extremely durable, with a long service life, this lowers demand for raw materials to produce replacement systems.
Achieving Sustainability Goals
MCM is an environmentally responsible and sustainable choice for the modern building. MCM meets or exceeds multiple sustainable design criteria. Choosing MCM contributes toward a project earning green building certifications and pushes forward the design and construction of healthier and more environmentally conscious buildings.
Environmental benefits begin in the factory. Shop-fabricated metal components reduce onsite labor, cycle time, and construction waste. The avoidance of waste is because MCM is precisely engineered and created to each project’s customized specifications. Production and fabricating facilities throughout the country offer the additional option of regional sourcing. Metal cladding components are factory coated with a 20-30 year warranted coating, and any volatile compounds (VOCs) are controlled at the coil coating factory, not released at the jobsite. Metal buildings offer effective insulation, reduced air leakage, and readily accept high-performance windows and doors. Daylighting and exterior views can also be easily incorporated into a metal building design to earn U.S. Green Building Council’s® (USGBC) Leadership in Energy and Environmental Design® (LEED) credits using metal composite material. All of these factors can be used to earn LEED points.
Under LEED v4.1, MCM panels are eligible for credits under the categories of Integrated Process, Sustainable Sites (SS), Energy & Atmosphere (EA), Materials & Resources (MR), Indoor Environmental Quality (EQ), Innovation (IN), and Regional Priority (RP).
MCM and LEED v5
Photo by Tim Hursley; courtesy of 3A Composites USA, Inc.
Recycled content, efficiency and performance, and reduced lifecycle impact are all attributes of MCM. Arkansas Children’s Hospital.
USGBC released LEED v5 in April 2025. LEED v5 is built around three central areas of impact: decarbonization, quality of life, and ecological conservation and restoration. Materials and Resources Category in LEED v5, points are awarded for choices focused on reducing embodied carbon, protecting health, and fostering a circular economy. This category addresses embodied carbon reduction through manufacturing innovations and circular strategies, improves indoor air quality, and supports ecological conservation.
While certain natural materials, like wood, may appear to have a more favorable carbon dioxide equivalent (CO2e) profile, this can be a misleading perception, as all impacts over the life of the product should be considered in responsible material selection. It is also important to consider the effect of service life on this analysis. A structure that lasts half as long as another should be considered as having twice the impact, for comparison purposes. With many green advantages over other materials, metal can reduce energy consumption, improve air quality and thermal comfort, help comply with energy codes, and minimize environmental impacts. MCM lasts longer, requires less maintenance, and is completely recyclable, unlike many other construction products.
A key step to avoiding embodied carbon is reuse. Metal is the only known construction material that can be recycled indefinitely with little impact on material properties, including strength. This allows it to be repurposed in the same exact form, a process called closed-loop recycling. Not only are excess and scrap metals such as steel and aluminum readily and easily recyclable, but it remains financially viable to recycle metal. This ensures that envisioned impact reductions will happen, instead of only existing “on paper.” Approximately 70 percent of an MCM by weight is recycled content.
Under LEED v5’s Building Product Selection Procurement Credit, the use of products with sustainability information is encouraged. The environmental, economic, and social impacts of the product are judged for how they align with industry momentum. This includes third-party product certifications, ecolabels, declarations, and standards. Additionally, the previous environmental product declaration credit is incorporated into this new credit.
The Reduced Embodied Carbon Credit addresses emissions over the entire building lifecycle. Points focus on material reuse and waste management practices. There are three options available to meet this credit: cradle-to-grave whole-building lifecycle assessment of the project’s structure (LCA); environmental production declaration (EPD) analysis for procured materials compared to industry average values; and tracking carbon emissions during construction activities.
Under LEED v5, Environmental Product Declarations (EPD) can either be product-specific or industry-wide. The LEED V5 reference guide states the following: “Project teams will compare their structure, enclosure, and hardscape targeted material types to product-specific Type III EPDs to demonstrate that the products they have procured have a lower embodied carbon intensity than typical across the industry.” Industry average could refer to an EPD itself, or to the use of EPDs to benchmark the embodied carbon of a building project.
When making efforts to avoid embodied carbon and secure environmental benefits, look for MCM products that are supported with LCA documentation. Coupled with clear, simple material ingredient reporting in the form of HPDs and Declare labels, EPDs, and other LCA disclosures help in meeting LEED, WELL, and additional guidelines on many levels. Environmental Product Declarations (EPDs) provide LCA-based information and details about the products’ environmental aspects and assist purchasers and users in making informed comparisons between products. MCM EPDs contain valuable information about product definition, building physics, the basic material and its origin, product manufacture and processing, in-use conditions, life cycle assessment results, and testing results and verifications. MCM products lend beauty, durability, sustainability, and fire protection to projects with a multi-generational impact in mind.
ENDNOTES
1Citation: Barrelas, J.; Dias, I.S.; Silva, A.; de Brito, J.; Flores-Colen, I.; Tadeu, A. Impact of Environmental Exposure on the Service Life of Façade Claddings—A Statistical Analysis. Buildings 2021, 11, 615. Accessed October 7, 2025.
Amanda Voss, MPP, is an author, editor, and policy analyst. Writing for multiple publications, she has also served as the managing editor for Energy Design Update.
