Metal Wall Panels

Summary

Metal wall panels are formed steel or aluminum sheets, or sandwiches of two metal skins around an insulating core, fixed to a wall frame as cladding or a complete enclosure. Insulated metal panels combine insulation, air, and water control in one product, but their foam cores bring fire testing and thermal-rating questions that need checking at design.

Cols

Image

Insulated metal panel (IMP): two metal skins bonded to an insulating core, forming one assembly that gives thermal, air, and moisture control
ACM (aluminum composite material): two aluminum skins around a core, used as a flat rainscreen panel
Core: foam insulation between the skins; polyisocyanurate is common
Panel joint: tongue-and-groove or shadow-line joint between panels
Profile: the rib or corrugation pattern of the face

Standards

Thermal performance

One manufacturer lists a 2 in. core at about R-16.7 and a 4 in. core at about R-33.3, or about R-8.3 per inch
Other polyiso-core products are rated about R-8 per inch; one line lists 2 in. at R-16 and 3 in. at R-24
A profiled panel's R-value cannot exceed that of a smooth panel at the same minimum thickness

Test standards

NFPA 285: full-scale facade fire test for walls with combustible components; manufacturers publish passing assemblies for foam-core panels
AAMA 2605: high-performance coatings for aluminum and metal finishes

Materials

Steel and aluminum skins: formed or flat sheets
Polyiso and other foam cores: insulation in IMPs
Coatings: high-performance finishes for color durability

Detailing

Confirm panel joints, clips, and fasteners with the manufacturer's tested assemblies
Check NFPA 285 listings for the whole wall assembly, not only the panel
Seal panel joints and transitions to windows, doors, and roofs for the air and water barrier role
Plan expansion movement and panel layout around openings
Specify the finish and warranty with the coating standard

Uses

Specific uses

Commercial, industrial, and institutional walls
Rainscreen and accent facades

Pros and cons

Pros

One product gives cladding, insulation, and air barrier
Factory-made panels

Cons

Foam cores need fire testing for the wall assembly
Panel joints and flashing are critical

Manufacturing and cost

Construction

Metal skins are roll-formed or flat, then foamed or bonded to a core in a continuous line, cut to length, and shipped for field assembly

Main manufacturers and suppliers

Trade association: Metal Construction Association.

Sources

Construction Specifier: a deep dive into insulated metal panels, https://www.constructionspecifier.com/?p=214208
Falk: performance ratings, https://www.falk.com/en-us/resource-library/testing
Metl-Span: fire safety of insulated metal wall panels, https://www.metlspan.com/wp-content/uploads/2022/11/0718-Fire-Safety-of-Insulated-Metal-Wall-Panels.pdf
BNP Media: insulated metal panels, an all-in-one air and water barrier, https://continuingeducation.bnpmedia.com/article_print.php?C=1710
Metal Construction Association: all in one, https://metalconstruction.org/view/download.php/online-education/education-materials/architect-resources/all-in-one