As well as being a natural resource and having timeless aesthetic appeal, there are many reasons why terracotta should be considered for rainscreen cladding.
Terracotta has been a popular material in construction since antiquity and continues to prove its value in the modern day through its use in advancements such as rainscreen cladding. Terracotta panels are made by shaping refined clay through extrusion or molding, then drying and firing it at high temperatures (1,000–1,300°C). Depending on design requirements, they can be left natural or glazed for colour and durability.
The physical build-up of terracotta panels and how they are formed provide many benefits for use in rainscreen cladding systems.
sustainability
As mentioned earlier, terracotta is made from clay meaning it’s natural, widely available and doesn’t require as much processing as synthetic materials. Terracotta is essentially heated clay, so the manufacturing process is simple and eco-friendly as it doesn’t involve harmful chemicals. In fact, the carbon emissions per ton of terracotta are lower than those from alternative materials such as steel and aluminium.
Another sustainable aspect of terracotta is that it’s fully recyclable thereby reducing landfill waste.
suitability for passive design
Another benefit of terracotta is that it’s a natural insulator making it a great option for developments with Passivhaus and net zero requirements. Terracotta panels create a thermal barrier that helps to reduce heat transfer and regulate indoor temperatures without the need for additional cooling systems. When used as part of rainscreen cladding system, it can help reduce U-values with the added help of an insulation layer. However, the thermal performance of terracotta cladding depends largely on the brackets used for installation, as fixings are the primary points of heat transfer. Therefore, it’s crucial to consider specialised thermal brackets to enhance efficiency.
DURABlility
One of the reasons terracotta has remained near the forefront of building materials is due to its durability. During manufacture, terracotta undergoes vitrification, which is the process of transforming a material into a glass-like, non-crystalline solid through heat. This makes the terracotta very robust against extreme weather conditions such as high winds, UV rays and heavy rainfall.
Despite its durable nature, terracotta is also very brittle and should therefore be handled and installed with care to ensure longevity.
FIRE SAFETY
There’s no doubt that aluminium is the frontrunner when it comes to façade materials. However, one advantage that terracotta has over aluminium is that it’s naturally A1 fire-rated.
As terracotta is produced using very high temperatures (over 1,000 degrees Celsius or 1,830 Fahrenheit) it does not burn, making it fireproof. Aluminium, on the other hand, can only be classed as A1 rated following anodisation.
This makes terracotta a great choice for rainscreen cladding following the introduction of the Building Safety Act which stipulates that all cladding materials used on ‘higher risk’ buildings should be a minimum of A2 fire rated.
AESTHETICS
The final benefit to be discussed in this article is terracotta's doubtless aesthetic appeal. Its rich red hues have appealed to architects for centuries and provide a great option for achieving a natural, earthy aesthetic. For Royal Oldham Hospital, the architects specified terracotta in order to reflect Oldham’s industrious mill history.