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An Updated Aesthetic

Metal wall retrofits revitalize older, outdated buildings

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Hubbard Street Dance Center in Chicago. {Photo courtesy of Tuschall Engineering}
Instead of tearing down an older and outdated building, one way to revitalize its appearance is by doing a metal wall panel retrofit. By adding metal wall panels to the exterior of a building envelope, an existing building can be completely reinvigorated and new life can be brought to both its appearance and the companies inside.

There are many reasons to do a metal wall retrofit. James C. Tuschall, president of Tuschall Engineering Co. Inc., Burr Ridge, Ill., notes that they include the repurposing of a building; a failed system, such as masonry deterioration; reconfiguring of doors and windows; and updating the visual appeal for a more competitive lease or attractive sale.

As David Rassmussen, business development at MG McGrath, Maplewood, Minn., adds that many commercial buildings constructed in the last 40 years feature wall assemblies with underperforming air barriers, drainage planes and insulation planes. “Metal wall panel technologies offer the possibility of improving the performance of these walls, while modernizing the appearance of their retrofitted façades,” he explains.

Working together with the building owner, developer, contractors and architects, it is possible to successfully renovate an existing building into one that is more comfortable, functional, energy efficient, and all done in a cost-effective manner. Renovating the exterior of a building can lead to increased commercial value, while allowing the building to be easily adapted for a completely different use than its original function.

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A canopy renovation at the River East Art Center in Chicago. {Photo courtesy of Tuschall Engineering}

INCREASED ENERGY PERFORMANCE

An advantage of doing a metal wall retrofit is the ability to update a building to meet current building code requirements while increasing its value, comfort and energy efficiency. By adding insulation, or using insulated metal panel systems, architects can create a tighter building envelope.

“In addition to addressing aesthetic considerations, many aspects of building performance such as the wall structure, drainage plane, insulation plane and air barrier can be improved,” Rassmussen says. “When retrofitting an existing wall to perform to contemporary standards, similar considerations must be extended to the proposed assembly. While not suitable for all applications, metal wall panel technologies offer the possibility of improving the performance of existing walls while simultaneously modernizing the appearance of their retrofitted façades.”

Rassmussen goes on to say that metal wall panel systems invite wall components to be optimally positioned for energy performance. “In cold climates, if the weather-resistant barrier also serves as an air barrier and vapor retarder, it can be positioned behind the insulation and extended to interface with the roof vapor retarder and foundation waterproofing,” he explains. “These advantages are particularly appealing when retrofitting a solid masonry wall because installation of these components can be accomplished from the building exterior with minimal disturbance to the occupants.”

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Renovation project using VM Zinc metal wall panels. {Photo courtesy of Tuschall Engineering}

STRUCTURAL EVALUATIONS

According to Tuschall, the benefits of doing a metal wall panel retrofit include saving the expense of demoing, the necessity of keeping the building weathertight during re-siding, and not disturbing the building’s interior finishes. When working on retrofit metal wall projects, Tuschall recommends being mindful of the load calculations, any necessary insulation upgrades, along with the overall condition of the existing wall and the structural attachments.

“A structural evaluation must be made of the existing wall assembly by a registered design professional,” explains Rassmussen. “The physical condition of the wall should be assessed to determine which components are serviceable. For retrofit applications, pull tests can be made of the prospective fasteners in the field to confirm their ability to achieve their design strength in the existing substrate. Such fasteners must consist of materials resistant to corrosion—galvanic and otherwise.

"Since metal wall panel assemblies are positioned outside the thermal envelope, they are subject to cyclic expansion and contraction due to changes in both ambient and surface temperatures. Provisions for thermal movements commonly include: combinations of fixed and sliding anchorage points—both for the panels and support systems which will utilize oversized or slotted holes on face-secured systems and metal panel length limits.”

When connecting a retrofit metal wall panel to another building type, such as brick, Tuschall says you should be aware of fastening pullout testing; alignment or need for shimming; and the condition of the mortar. The biggest challenges, he says, are engineering the fastening and identifying vulnerable areas that are susceptible to water infiltration.

“It’s critical to make sure that what you’re fastening to stays on,” Tuschall explains. “Retrofitting can be installed over just about any material—Dryvit, stucco, brick, structural steel—and fasteners are critical to make sure whatever material we’re fastening over, stays on.”

Other challenges, Tuschall notes, include tying into the roof and making sure you have the proper flashings at the windows and penetrations. It is also important to work safely around electric power lines.

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A metal wall retrofit project completed by Tuschall Engineering. {Photo courtesy of Tuschall Engineering} 

“Metal wall panel technologies offer the possibility of improving the performance of [underperforming] walls, while modernizing the appearance of their retrofitted façades.”

- David Rassmussen, business development, MG McGrath

UPDATED FAÇADE

Another benefit of updating an older building with a metal panel retrofit is that it allows the building to remain occupied. Updating a building’s façade gives owners and designers the option to enhance, define or even redefine the entrances and exits. “Improvements can be made to egress, ADA compliance, security, and overhead sun/rain/snow/ice protection,” Rassmussen says. “Façade retrofit schemes can often accommodate the introduction of canopies and awnings.”

Rasmussen adds that if a building is to remain occupied throughout the course of the project, building entrances and egresses need to remain operational and protected. “If doors and windows are to be replaced as part of the project, some minimal disturbance to the building occupants should be anticipated,” he says. “As such, a phasing plan should be developed for the occupants wherein swing space is made available to those temporarily affected by replacement operations. Considerations might also be required for temporary security measures while windows and doors are being replaced. The building owner will need to be able to maintain the installed metal panel assembly. As such, consideration should be given to the durability and ease of repair for any given panel system. Panel returns should be designed in such a way that they need not be removed to facilitate future replacement of doors and windows.”