Photo courtesy of Kingspan Insulated Panels

Recladding with insulated metal panels is a great way to boost energy efficiencies and occupant comfort while delivering a refreshed, updated look as was done here for the decades-old 808 Memorial Drive apartment buildings in Cambridge, Mass.

Checking all the boxes for high performance, sustainability, longevity, aesthetics, and affordability, insulated metal panels for wall and roofing systems are an increasingly popular option for a wide range of projects from healthcare to schools to offices to recreation to retail to multifamily, and the list goes on. Delivering air, water, and moisture protection, together with unmatchable thermal performance, Insulated Metal Panels (“IMPs”) are a fantastic “one and done” option for building enclosures. The versatile panels are also gaining traction in the growing retrofit market as building teams look to refresh and update their cladding and roofing systems with tighter, better-performing enclosures.

“Insulated metal panel retrofits for roofing and walls offer both the practicality of a lightweight, continuously-insulated skin and the design incentive of clean lines, durable finishes, and integrated detailing,” states Colin Drake, FAIA, LEED AP, principal, JRA Architects, Louisville, Ky. Bruner/Cott Architects also chooses IMP cladding and roofing systems for many of their retrofit projects on account of the product’s versatility, ability to meet and exceed energy code requirements, and its adaptability for historical renovation projects.

Presently, the market for IMPs is approximately five times larger in Europe than in North America. But as more projects are installed and the building market learns more about the technology, U.S., and Canadian projects are anticipated to grow. Before delving into IMPs compatibility with retrofit projects, it’s important to appreciate the extent to which the market has evolved in recent years.

RETROFIT BOOM

While an increased focus on building retrofits traditionally occurs during economic slowdowns when there isn’t as much capital to fund new development, something changed a few years ago. In a recent American Institute of Architects report entitled “Renovate, Retrofit, Reuse: Uncovering the Hidden Value in America’s Existing Building Stock,”¹ the authors explain that following the Great Recession in 2008- 2009, retrofit projects increased significantly and have remained a strong percentage of all construction projects ever since then. In fact, in the spring of 2022, retrofit work surpassed 50% of the market for the first time, overshadowing new construction. “New highs in boom-time renovation work represent a shifting trend with significant implications for the profession and for the environment,” states the paper. “Even as the economy has recovered from the Great Recession-and the construction sector has surged in recent years–the proportion of architects’ work on existing buildings has held steady.” “The most logical thing we can do to decrease our impact on the planet is to reuse what already exists,” stated Jean Carroon, FAIA, Goody Clancy. Really driving this point home, Carl Elefante, former president of the American Institute of Architects is famously quoted as saying, “The greenest building is the one that already exists.”

Photo courtesy of Nucor Insulated Panel Group

A former factory-turned-school, Essex County West Caldwell School in West Caldwell, N.J., recently received another facelift with IMP wall panels to boost thermal performance and help convey to help convey the high-tech, modern look the school was after.

As interest in issues like health and well-being, social impacts, biodiversity, and climate resilience rise in importance, particularly in more architecturally progressive markets like California, New York, and Boston, owners and architects are taking a more serious look at building retrofits and renovations and reroofing and recladding. As stated in a “Retrofit Revolution” report² by the UBS Sustainability and Impact Institute, “the existing building stock is mostly energy inefficient, and adversely impacts the health and comfort of inhabitants, leading to costly medical, social, and economic outcomes. Retrofitted buildings that are better insulated, better ventilated, and smarter reduce emissions and the strain on grids as the economy electrifies while improving health outcomes,” while buildings age and older facade systems are no longer delivering acceptable levels of energy efficiency and occupant comfort, not to mention aesthetics. Instead, the building codes and the marketplace are demanding more. For example, Class B and Class C office buildings are finding it difficult to fill occupancies, particularly if the building is drafty and tired-looking with high energy bills. This summer, Moody Analytics reported that office vacancies had hit an all-time high of 20.1%, breaking the 20% barrier for the first time in history. In all, a whopping 1 billion square feet of office space in the U.S. is sitting vacant.

While upgrading the building enclosure is not a low-cost nor low-hanging fruit approach to increasing a building’s value in the short term, it is a very viable longer-term investment, which shouldn’t be overlooked. Further more, destroying and replacing the building is certainly higher cost than retrofitting an existing building. A new facade upgrade is not going to deliver that quick ROI. However, such an investment will optimally position the property towards where the market is headed. “Take a building that today is worth $100 million and requires a $15-million upgrade. That may never pencil out on an operating-cost break-even basis. But as tenant demand for low-carbon buildings accelerates, there’s a risk that the building’s value falls because it’s unable to meet the tenants’ low-carbon targets, which in turn affects the number of potential future buyers. On the other hand, low-carbon space can earn a substantial premium from retrofit investments,” states Greg Bolino, Head of Global Sustainability Strategy & Assets, JLL. In the shorter term, rising energy costs, market pressure to meet sustainable building certifications, and developing codes and standards are making reclads and roofing retrofits more viable.

Photos courtesy of Kingspan Insulated Panels

IMP’s insulation capabilities and speed to erection helped drive Holly and Smith Architect’s selection of the colorful wall panels for Mandeville High School in Mandeville, La.

UNDERSTANDING IMPS

Before delving into some details and best practices for recladding and reroofing buildings with IMP systems, a general overview of the technology and its benefits is in order. IMPs are made from two sheets of metal sandwiched with rigid insulative foam core. In addition to servicing as an all-in-one air, water, and vapor barrier­­-fully tested for structural, thermal, and fire protection performance-IMPs deliver exceptionally high thermal performance with complete insulation. In fact, at R7 to R8 per inch, IMPs are one of the greatest pound-for-pound materials in the marketplace when it comes to thermal value per inch. As a point of comparison, the R Value per inch of other types of common insulation materials is R5 for extruded polystyrene, R4 for expanded polystyrene, and R3 for mineral fiber and cellular glass. Virtually eliminating thermal bridging, the system serves as a full thermal barrier, which is becoming a code requirement in many municipalities. Highlighting the significance and importance of thermal performance, the Building Science Corporation (BSC)³ performed a study comparing IMPs to other enclosure systems. The building scientists point out that typical roofing installations are challenged with thermal conductivity through the steel framing/studs and air leakage through and around improperly installed internal frames or cavity insulation. These issues combined can reduce the effective thermal resistance of the assembly by over 50%. Consequently, a fully insulated wall is the best way to avoid this.

In comparing IMPs to blanket insulation purlin roof systems, these systems are challenged with thermal conductivity issues and therefore do not provide comparable performance to IMP roof assemblies. For non-insulated, i.e., concrete tilt-up and insulated mass wall assemblies, BSC says they are problematic in hot humid climates and mixed humid climates as the latent load of the outdoor air introduced by the humidity makes it difficult to use ventilation air for energy removal at night. In addition, they are problematic in cold climates because the interior surface of the mass wall stays below the comfort level as there is insufficient thermal energy available from the exterior. “Insulated metal panel systems provide all the required functions needed from a proper building enclosure with less materials needed to install and provide a better performing, energy-efficient building,” states the study.

While these insulating values gave IMPs their start in cold storage, manufacturing, and processing facilities which required climate-controlled environments, the products’ durability, light weight, and appealing aesthetics have significantly expanded their reach to healthcare, education, recreation, transportation, offices, and hospitality facilities. The panels integrate well with customized windows, louvers, and sunshade systems, and like other metal roof systems, they serve as a great platform for solar photovoltaics. And because they are pre-assembled as a fully integrated building envelope system with a high level of quality control, this better ensures performance and uniformity in appearance.

IMP wall and roof panels come in a wide range of custom shapes, print patterns, colors, and finishes. Architects can tap into the creative possibilities of forming dynamic curves, geometric patterns, and everything in between. Panels can be smooth or textured in a variety of expressions including striated, fluted, grooved, or embossed. This flexibility enables designers to fit their facade and roofing designs within the context of the surrounding architecture and style. “I have seen quite a bit of design flexibility with these systems,” observes Alexander Zilberman, AIA, AZA-Alexander Zilberman Architecture, New York City. “You can have a standing seam profile, modularize it and you have the benefit of a factory finish-either off the shelf or a custom finish, including anodized finishes.”

Zilberman also likes IMPs' bespoke capabilities and their ability to integrate with an array of products like fascias, rakes, soffits, and gutter systems. But the fact that IMPs incorporate air, water, vapor protection, and thermal performance within one system is key. “As a designer, it frees me because it’s unnecessary to detail all those components or figure out how it works with other manufacturers’ products. So you are picking things off of a menu, in this way,” he says.

Eliminating the need to interface with multiple components and manufacturers for the building enclosure design and installation, boosts performance, prevents installation errors, simplifies the design, and expedites design, procurement, and installation. The pre-assembled IMPs arrive on-site ready for installation. The lightweight of the panels makes them easier to install. And as full thermal, water, air, and vapor-tight enclosure, the sequencing of construction and permits can be fast-tracked. This not only minimizes the risk of adverse weather slowing down construction but also enables project teams to get started on the interior work much quicker. Depending on job complexity and size, IMPs can be erected at a rate of up to 5,000 square feet per eight-hour shift by a four-man crew on an industrial project and up to 1,100 square feet during an eight-hour shift by a four-man crew on an architectural project when proper lifting equipment is used. Case in point, Zilberman recently specified IMPs, together with composite aluminum panels for the roof of a large retail complex in New York. As the most efficient and effective roofing system to install, the panels added significant insulation and energy efficiencies. and enabled the mall to meet all its design and building code requirements.

While lighter-weight roofing systems are of benefit in many applications, this advantage is particularly poignant with aging structures and in seismic zones. The lighter-weight panels can be installed in larger spans. As compared to conventional cladding, which requires screws every few inches to secure the panels to the structure, IMPs reduction in anchor points significantly minimizes the risk of air and water infiltration, and thermal bridging.

On the topic of sustainability, the metal facings are 100% recyclable and incorporate a minimum of 30% recycled content. The insulating cores meet current U.S. Environmental Protection Agency requirements for global warming potential reduction, VOC content, and have zero ozone-depleting potential.

As for longevity, an oft-quoted study performed by the Metal Construction Association and ZAC Association,⁴ with oversight from three independent consulting firms, found that a low-slope, unpainted 55% Al-Zn coated steel standing seam roofing system can last as long as 60 years. And like all metal shingles, IMPs undergo aggressive structural performance testing. Structurally, IMP roof panels offer a high strength-to-weight ratio. In addition to their strength and insulating properties, the panels are highly weather- and corrosion-resistant, making them appealing for cold climates and coastal regions.

Photo courtesy of Kingspan Insulated Panels

At the Gusto 501 restaurant in Toronto, insulated metal panels in varying shapes and cascading designs were selected for their aesthetics, cost savings, and speed to construction.

Photo courtesy of of Wood's Powr Group Co.

IMPs can be erected at a rate of up to 5,000 square feet per eight-hour shift by a four-man crew on an industrial project.