INSTALLATION STRATEGIES

While the embodied carbon, labor, and cost savings associated with IMP recladding and reroofing while using the existing structural system are significant, the process of aligning and attaching the new panels to the substrate can be challenging. Whereas “ground-up IMP projects get to make the rules and dimensional tolerances that best suit the new building, overcladding projects require the team to respond to the dimensional parameters set by the existing structure and then form a framework and dimensional guidelines that respond and intersect with the existing topography of the vertical surfaces or facade of the existing building,” explains Jewhurst. Furthermore, building teams must contend with a certain level of unpredictability regarding the state of the existing substructure and the substrate to which the new panels are being attached. If the structure is flawed or degraded, this can impact the quality of the installation and the IMP warranty.

To help mitigate this risk, Drake recommends inspecting the substrate, and, if possible, probing the structure. It is also best practice to confirm that the receiving structures and surfaces meet the manufacturers’ requirements. “Structural design must be front and center when applying a new skin over an existing envelope. Whereas a new building can count on a fully code-compliant assembly, and typical material attachment, over-cladding demands attention early on to be sure that the new, high-performance skin has adequate support,” he states. This involves reviewing the specifics of the detailing with the IMP manufacturer and structural engineer to best ensure compatibility, as noted.

Vo agrees that structural support for the new cladding system is the most important item to design and engineer from the onset of a project. One strategy he suggests is leaning into the unitization and prefabrication capabilities of IMP systems. To optimally execute this, it’s important to establish sizes and spans for unitization that will meet engineering requirements and existing building parameters.

Another best practice, says Drake, is vetting the right IMP product for the job. “It’s even better to confirm integration with numerous reputable manufacturers to assure competitive bidding and the best system for the project’s unique challenges” he explains. “These are very efficient panel modules, but only when they arrive on site prepped for a project’s specific parameters.”

Important details include flashings at transitions, penetrations, curbs, terminations, and panel end lap. “Detailing is everything for wall retrofit success,” emphasizes Drake. “Flashing conditions at openings, coordination at the top and bottom of panel transitions, and effective planning for unique penetrations are no less critical than any other assembly. Attention to detail for air and water management, as well as care for the inevitable, atypical moments on a building, set a project up for success.”

Photos courtesy of All Weather Insulated Panels

Using vacuum suctioning, IMP roof, and wall panels for Wood's Powr-Grip’s manufacturing facility were installed in just two weeks.

ROOFING PROFILES AND INSTALLATION

For IMP standing seam roofing systems, both retrofits and new construction, the product offers the advantage of ease and speed of installation. As opposed to multi-piece field-assembled metal systems or built-up roof systems, which require several individual layers and components, an IMP installation includes one step because all the components are contained within the panel. This simplified installation process delivers labor savings and shorter project schedules. In addition, interior work can then begin sooner.

IMP roof panels come in two profiles: standing seam and through-fastened. The standing seam profile roof panels are typically mechanically seamed together during installation with no exposed fasteners within the envelope boundaries. The fasteners that connect the panel to the roof framing are covered when the next panel is joined to it. A traditional joinery is a standing seam panel with a 2-inch straight leg, and some manufacturers offer panels with a T-shaped joinery and or trapezoidal joinery The latter option has a 2-inch leg and a trapezoidal lower half, creating a panel installation with greater dimension across the face of the roof. Through-fastened profiles have exposed fasteners. Though not as aesthetic, they offer the advantage of faster installation because they do not require that the installer mechanically seam the panels together.

A noted benefit of IMP systems is the nature of the sandwiched panels means there is no significant linear differential expansion between the interior and exterior facings. Instead, the expansion of the panel is distributed among the individual spans as curvature, which is called thermal bow. Because the overall panel does not significantly elongate or contract, there is no need to install an IMP roof panel with slotted clips.

IMP roofing installs also require the creation of an end lap on the panel at the perimeter of the roof to be able to perfectly fit the panel onto the roof. To create an end lap, installers typically cut away the inner-facing liner and foam core, leaving a small exterior-facing extension that will then lap over the lower panel. The length of the extension and end lap is dependent on the slope of the roof and panel profile. The end lap joints are caulked and fastened according to the roof panel manufacturer’s recommendations. The tool for cutting should be designed to cut metal panels. Reciprocating saws are not recommended.

When lifting the panels, a common method is wall clamps. At least 12 gauge is recommended. Though more common in Europe, vacuum or section lifting can be a very safe, efficient method.

CONCLUSION

In sum, a number of variables are driving interest in retrofitting older buildings and, particularly, recladding, and reroofing projects. Growing concerns about energy efficiency, sustainable design, the use of resources, operating expenses, energy use, labor, and incentives are all encouraging building owners to consider renovation over new construction.

Generally speaking, as reported in Metal Architecture magazine, metal roof shipments are expected to grow 5% this year, the metal wall market is expected to be approximately $2.8 billion by 2025, and IMP adoption is contributing to this growth. Essentially, industry experts anticipate that North American IMP applications will begin catching up with popularity in Europe. “Predicted growth in the industries that are well suited for IMPs will result in commensurate growth in the use of IMPs,” agrees recently retired industry consultant Brian Gardiner, FRCI, RRC, CCS.

Meanwhile, experts anticipate IMP roofing and wall renovations will play a significant role. “We anticipate IMP retrofits will become more prevalent in the coming years, especially with 70s Brutalist architecture and the updated energy requirements. If planned properly and thoughtfully, overcladding will have less impact on the occupants and property overall,” states Vo. In conclusion, Zilberman predicts, “Expect more bespoke projects. As manufacturers are being challenged by project-specific scenarios, there will be more and more opportunities for custom, design-specific applications. These will help design teams achieve both performance and aesthetic for all projects.”

END NOTES