A Guide to Commercial Cladding

The basic function of cladding is to enclose or envelope a building in order to offer an elegant finish and to protect the interior spaces from the surrounding environment. The exterior cladding on a building forms a finish or protective layer that is fixed to the exterior side of enclosure system of the building.

Commercial cladding solutions consist in a wide variety of synthetic and natural building envelope materials, systems and components. Synthetic and manmade elements are typically derived from the available raw materials and developed to render them suitable for use as exterior enclosure of a building structure. They are selected for the climatic conditions and exposure specific to the geographic region where the building is raised. 

Exterior cladding is the first line of defense against rainwater and plays a role as a precipitation management measure. The drainage plan of a wall system consists of any element that is exposed to weather. Depending on the climate, material selection, and wall type, this plan is intended to be vapor impermeable, water resistant or water proof. The drainage plan has the role to shed condensation and bulk rainwater in order to prevent water penetration into the interior spaces of the building.

This plan is usually residing at the line between the wall system’s “dry” and “wet” zones. The section of an exterior wall system called “wed zone” is exposed to the short and long-term effects of moisture ingress and bulk rainwater penetration. This zone is typically located on the outboard side of wall system’s innermost drainage plane. The wall system’s section that is not exposed to the short and long-term effects of moisture ingress and rainwater penetration is called the “dry zone”. This dry zone is typically located on the inboard side of wall system’s innermost drainage plane. For this zone are can be used materials with low storage capacity for moisture and relatively low moisture tolerance.

In a barrier wall system, the exterior cladding serves as primary line of defense against rainwater penetration and as the principal drainage plane. However, in cavity wall construction the primary line of defense against rainwater and the principal drainage plane are located on the inboard side of the air space, inside the wall cavity.

Depending upon the direction of vapor flow across the wall system, this can lead to moisture in the “dry” zone of the wall. This can result in moisture degradation of gypsum wallboard, wood and other moisture sensitive materials, concealed corrosion of fasteners, mild steel anchors, metal studs and other related accessories and components, and potential mold growth.

In order to address this concern, it is advisable a climate-specific hydrothermal analysis of moisture transfer through the exterior wall design. The analysis will find the proper material selection of the commercial cladding and each layer of the exterior wall system. Special insulating elements might be also desirable in order to regulate or control of heat gain and loss across the exterior wall assembly.

Other elements that should be taken in consideration in designing the commercial cladding of a building are the structural elements. They are included in an exterior wall system in order to effectively protect to wind and other loads acting on a building. Building design aim to select the proper elements in the exterior wall system in a manner that allows for a thermally efficient, fully integrated, and weather tight building envelope.