The architectural design of buildings often elevates the demand for aesthetically pleasing exteriors. At the same time, the performance qualities expected from cladding — wind resistance, air infiltration, water resistance and fire safety — must be maintained. IAPMO Uniform ES recently published EC011, the Evaluation Criteria for Single Skin Steel Roof and Wall Panels with Concealed Fasteners, which sets forth guidelines for compliance with the International Building Code (IBC) and the International Residential Code (IRC).

Concealed fastener panels typically rely on nails or screws for attachment to the structure. These fasteners may either secure the panel itself or a separate clip element. To hide the fastener from exterior view, an interlocking arrangement of the seams is formed. Figure 1 illustrates some of the commonly available seam types.