Its use can be traced back over 4000 years when it had extensive use in palaces, temples and statues. As a building material, terracotta has been used for thousands of years — and is likely to continue for thousands more.
Terracotta cladding is gaining a resurgence as natural facade cladding as architects and designers look at natural, textured and eco-friendly building materials that can add vitality to new building designs.
Refer to our article titled “How to Specify Terracotta” for design inspiration using terracotta as a cladding material.
Once a decision has been made to include terracotta cladding as your building façade, there are several aspects of design that need consideration, below are the key components.
Modern-day construction typically relies on two main methods to cladding a building in terracotta. These include rainscreen and precast concrete installations.
1. Rainscreen
The most common method of installing terracotta cladding is as a rainscreen – the panels are installed onto an aluminium support system designed to support the cladding on the building's substrate.
This method creates a continuous external barrier made from the terracotta panels with overlapping joints; designed to drain water away from the cavity that lies behind the panels.
A rainscreen façade is a two-level construction system which provides superior waterproofing, condensation control, long term durability and thermal efficiency.
Rainscreen system – designed to reduce water ingress and facilitate better airflow behind the façade.
When rain and wind force moisture towards the building, the majority is deflected by the terracotta outer layer, the primary weatherproof layer. The moisture that penetrates through the outer layer is then effectively managed through ventilation and drainage in the cavity between the primary weatherproofing layer and the secondary weatherproof layer. Rainscreen systems utilise airflow and ventilation to insulate buildings and minimize exposure and damage caused by the elements.
These rainscreen facades are designed to provide effective drainage and create convective airflow up the cavity. Warmer air within the cavity rises and draws cooler air in from the base of the wall, helping to keep the building mass cool as well as providing evaporative drying in the cavity for moisture and condensation management.
The Clayton terracotta cladding system is an exterior wall system with a ventilated cavity that acts as the primary weatherproofing layer preventing wind-driven rain from reaching the structural wall, allowing the wall cavity to breathe, and preventing mould build-up within the cavity. Being an open joint system, the air is able to circulate effectively through the joints so as to minimise pressure differences between the inside and outside cavities.
2. Precast Concrete:
The alternative method to Rainscreen installation involves fixing the terracotta to precast concrete panels. In this example a veneer is bonded onto large precast concrete units at the warehouse, once delivered to the site, these precast sections are then lifted into position and fixed to the building.
This installation method offers the strength of the concrete panels combined with the look of terracotta when viewed outside. This option allows for various profiles to be fixed to the precast sections; therefore, loss of design flexibility is not a concern.
The advantage of this method is the strength offered by the precast concrete panels and the speed of installation at the site. This is due to the individual terracotta panels being installed at the warehouse prior to going to the site.
However, care does need to be taken, as ongoing maintenance of the joins between the precast sections is required in order to ensure a weathertight second barrier is maintained throughout the life of the façade.
Across Australia, the most common installation method for facades is the Rainscreen method. Over the years the industry has become accustomed to working with this design with a resulting high degree of reliability and durability in the long term.
As an extension to cladding, terracotta is gaining a lot of interest in applications such as sunscreens.
Terracotta baguettes are designed to act as a sunscreen to reduce the amount of radiant heat striking the building while adding colour, depth and a distinctive modern appearance to any building.
Terracotta sunscreens are made as louvres and baguettes and are available in many colours, textures and shapes to provide an architect with full design freedom while maximising the thermal performance of the building.
These can be used in combination with terracotta panels in both internal and external applications to create unique visual effects, a uniform transition between elements, warmth, and maximum design flexibility.
Clayton offers a variety of baguette profiles available in various shapes and colours.
By reducing the amount of radiant heat reaching the building, terracotta sunscreens reduce the amount of solar heat gain through the façade and into the building, assisting in reducing energy use and environmental impact of the building. Louvres can be positioned to block radiant heat during peak summer months and allow radiant heat through during the winter months.
Clayton's range of Baguettes offers:
One of the key characteristics of terracotta is low heat transfer – a feature that holds its heads and shoulders above many products in the market.
A typical 3mm solid aluminium had approximately 8-9kg or aluminium mass per M2. Depending on the type of terracotta cladding, the weight could be over $40 kg/M2. Terracotta’s higher mass value means that the thermal performance of a building is enhanced by using this product.
The heat transfer process through the building wall occurs by conduction, convection, and radiation. For example, in the daytime, solar radiation hits the external wall surface, a part of which is released to the outdoor environment and the other part is absorbed and conducted across the material. The heat transfer through the building envelope depends on several factors but the key one that is a benefit of terracotta is the thermal mass.
Thermal mass is the heat energy the object can absorb and store. In the building, thermal mass can significantly minimise indoor temperature fluctuation and reduce the heating and cooling demand.
Terracotta panels, compared to lighter and thinner materials, have a higher mass and a higher density which will moderate the heat transferring into the building.
The higher thermal mass of terracotta makes it able to offer over four times better resistance to heat transfer when compared to solid metal products. When coupled with a rainscreen installation method, terracotta cladding offers even greater thermal performance. The circulation of air within the cavity helps remove any heat transferred through the terracotta which assists in reducing energy costs.
Using terracotta sunscreens can assist by further reducing the amount of radiant heat striking the façade and help supercharge the thermal performance of the building.
Common terracotta cladding installation is via the rainscreen method, where the terracotta panels are mounted onto an aluminium mounting system designed to offer durability, and airflow and significantly reduce the penetration of moisture into the cavity.
Clayton terracotta cladding system incorporates three installation methods:
Wall Bracket & T-Profile: This system features vertical T-Profiles anchored to the building using wall brackets. Clayton tiles are then secured to the vertical profiles using aluminium clips. Notably, this method allows for the maximum cavity depth, facilitating the incorporation of insulation within the façade cavity.
Top Hat: In this system, vertically mounted top hats are installed at predetermined intervals, depending on the building's loading requirements. These top hats serve as the substructure onto which the tile carrier is fixed, enabling the secure attachment of terracotta tiles to the façade.
Stud Wall: The stud wall system involves mounting the tile carrier rail directly onto the stud framing. This method offers the shallowest cavity depth while minimising the use of sub-framing components, thereby expediting the installation process and reducing costs.
The Clayton terracotta cladding system has been designed for simplicity, speed and durability. By creating a cavity behind the terracotta panels, you allow airflow to help improve thermal performance and moisture management.
Terracotta as a building façade offers great advantages over other building products which explains its use over several millennium and its increasing relevance in contemporary building designs today.
Key to this are the benefits of terracotta exterior wall cladding panels – these being:
If you haven’t considered using terracotta cladding for your building facade – you are missing out on a lot of opportunities to take your building design from ordinary to extraordinary.
No other product can boast the tenure as a building product that spans several millennium, is contemporary and offers characteristics that are still relevant in today’s building requirements.
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