How to Specify: Terracotta Cladding
Browse the Architizer Jobs Board and apply for architecture and design positions at some of the world's best firms. Click here to sign up for our Jobs Newsletter.Get more news about
,you can vist our website!
Throughout contemporary architecture, terracotta cladding is lauded for its design flexibility, distinctive colors, natural textures, durability and sustainability. Dating back to the Babylonians, who made wide use of terracotta in palaces, temples and statues, it is a proven material that has stood for thousands of years — and will likely stand for thousands more.
Architizer spoke with Christian Lehmann — Ceramic Engineer and General Manager of NBK North America — who helped us understand the ins-and-outs of terracotta, and its modern applications as a cladding material. Founded in the late-1920s, NBK Terracotta began as a roof tile company and later branched out into architectural terracotta. As a pioneer in the industry, NBK started using terracotta as a rainscreen cladding product for exterior walls in the 1960s.
“Using terracotta as a cladding product was not very popular at that time,” Lehmann said. This began to change when Renzo Piano began working on large-scale terracotta projects in Europe, demonstrating how the material could be used in new and creative ways. Completed in 1997, one of these projects was Potsdamer Square in Berlin, which features a bespoke curved terracotta façade. “Renzo Piano’s projects were breakthrough,” explained Lehman. “The big difference was that Renzo Piano had a lot of ideas about shapes and sizes, which showcased the adaptable and geometric possibilities of architectural terracotta.”
Categorization
According to Lehmann, there are two main approaches to cladding a building in terracotta: the rainscreen principle and precast concrete. Aside from these two approaches, in this section, we also touch on using terracotta pipes to create a sunscreen or brise-soleil effect.
Rainscreen Principle: One of the most common ways to install terracotta is based on the rainscreen principle. Terracotta panels are hung onto an aluminum sub-support system, offering the durability of a masonry installation without the added weight. Creating a continuous insulation outboard with overlapping joints, the system is carefully designed to drain water away from the cavity that lies beneath the support structure, thus protecting the building from rain, wind and snow. Many profiles, colors, finishes and other opportunities for customization are possible.
Another advantage of terracotta rainscreen systems is that they do not use grout or sealants such as silicone, thus avoiding the excessive number of joints associated with precast concrete panels. This greatly reduces the need for maintenance and also makes for an easier installation process that can be performed in all weather conditions.
“With a rainscreen application, terracotta is really being used to protect the building’s core, which will really prolong the lifecycle of the building,” said Lehmann.
Precast Concrete Panels: In this case, a terracotta veneer is bonded onto large precast concrete units. These systems are ideal for architects who are simultaneously looking for the strength of a precast concrete construction as well as the flexible design, profile and finish options offered by terracotta facing. “From the outside it looks like a terracotta building and from the inside, it looks like you have a solid concrete wall,” Lehmann said.
According to Lehmann, the upfront costs of precast concrete panels are typically less than rainscreen applications. However, many other costs will arise as you will have to maintain the joints between the concrete panels. Lehmann urges that if you have the budgetary flexibility, terracotta rainscreens are a shrewd investment that preclude unpredictable costs in the future.
