Cladding and sustainability: what are the best options?

The cladding you choose for your home is a vital part of expressing its style and accentuating the lines and character of the building. It is arguably one of the most important exterior design decisions and will define the home’s aesthetic for years to come. However, not all cladding is equal and in terms of sustainability there are a number of factors to consider. Here are four options, each offering a different perspective on what it means to be sustainable.

Timber is synonymous with our residential architecture. Conjure up an image of a Kiwi home and, chances are, classic weatherboards come to mind. However, despite being renewable, timber is not always the most durable of choices—especially for cladding which is consistently exposed to harsh environmental conditions. While we’ve used treated timber for decades, when it does come to the end of its life, the chemicals used for treating it mean it isn’t biodegradable and can’t be burned.

These issues ultimately led to the development of a range of alternatives including thermally modified timber, a viable and long-lasting solution that utilises no chemicals during the manufacturing process. Rather, its very makeup is altered during the modification process, which uses heat and steam. At the end of thermally modified timber’s life, it is biodegradable and not dangerous.

During the modification, in which the timber is exposed to temperatures of up to 190℃, the moisture content is removed and the chemical and physical properties are altered, giving it an extended durability without chemical intervention. It’s for these reasons thermally modified timber is favoured as a sustainable cladding option.

While concrete doesn’t often top the list of sustainable building materials, it is arguably one of the most durable, therefore, for this reason there is real merit in it being considered as a sustainable solution. The New Zealand Building Code states houses must last for a minimum of 50 years, with many building products required to last less than that. Concrete is likely to last significantly longer and, in fact, could be considered one of the most robust cladding materials, ensuring resources aren’t wasted in years to come as it outlasts almost all other options.

There are various advanced options for concrete cladding, including thin-format glass reinforced concrete options such as Rieder Oko Skin, which is an ideal alternative to timber facades made with concrete. 

Bricks are a classic cladding material and are widely used the world over. In terms of sustainability, they have various merits in terms of increasing the energy efficiency of a building and requiring virtually no maintenance over time. Sustainability is often considered in terms of the whole-of-life impact of a product or building, and this is where bricks come to the fore as a contender in the sustainability marketplace. When combined with the appropriate insulation, bricks can offer a thermal mass benefit that allows for the reduction of energy loadings and keeps your home warmer in winter and cooler in summer. 

Clay bricks are made from organic minerals found in abundant sources of clay, which means they are free from added contaminants and don’t require painting, sealing or any other treatment to ensure their durability and performance over time. Due to the high temperatures they are fired at, the colour of clay bricks will always remain the same and, at the end of their lifetime, they can be salvaged and reused or recycled.

Many metals are considered sustainable when it comes to cladding, both because of their ability to be recycled and due to their durability in many conditions. Copper, for example, is much sought after for high-end projects, coveted for its ever-changing appearance and striking patina it develops over time—depending on the environment it is exposed to. Aluminium is one of the most used metals in the world, and is a popular option for cladding. As a sustainable solution, aluminium is favoured for its durability, resistance to corrosion and its ability to be recycled without losing quality. Lastly, steel makes the list as it is one of the easiest metals to recycle without losing its integrity. 

Find out more about the best option for cladding materials for your next project.