Rethinking Use of Aluminum in Glass Facades
This idea is a part of The Circular Construction Challenge – Rethink Waste
Rethinking use of aluminum in glass facades
In most modern urban environments a great variation in building materials and facade solutions can be experienced – and along with it a growing attention to implement sustainable, recycled or up-cycled solutions, already available at the marked. In Denmark, we even experience a steadily increasing interest in circular pilot projects initiated by innovative architects, urbanists, contractors and authorities.
But one of those elements that sum up a significant material volume in modern architecture, especially buildings of a certain size, is the glass façade. And in those facades, the design and aesthetic expressions is continuously predominated by aluminum details. This one sided use of aluminum is not only far from a circular mindset, is also creates lack of variation in the build environment and thus in our cities.
Our idea for the Circular Challenge is focused on rethinking the aluminum ’cap’ on glass facades: the profiling exterior element that is a main part of the impression of the overall facade design. In a large part of modern glass facades, the cap has no structural or mechanical importance for the façade’s function as building envelope.
Circular mindset and architectural value
It is close to our hearts that a circular approach in the building industry addresses sustainable, architectural and technical value as one. This way, we can collectively become more conscious of the solutions we actually have to reduce the resource impact in the building industry. We think it is crucial that a circular mindset becomes so ‘ordinary’, that we do not think of circular choices or solutions as something special, but rather as an enriching and integrated part of the full palette of possible solutions.
There are primarily two reasons why we see the aluminum cap in glass facades as an obvious component in which to pair a quite ordinary building detail with the principles of reuse and a circular approach in the building industry: rethinking such a mass produced detail, we can actually reduce waste and energy consumption in large quantities and at the same time create a larger variety and a richer materiality in the build environment.
We are taking the first steps in the process towards possible solutions, budget, material alternatives and more precise considerations of possible collaborators etc. But we feel that the idea has a great potential to reduce the use of raw materials, to reduce the amount of waste produced in the industry and at the same time has the potential to create higher architectural value.
In this short presentation, we are focused on outlining the potential of the idea and thus see the more detailed solution scenarios as part of the development to take place under the Circular Challenge program.
A small detail with a big potential
The curtain wall glass façade has over time developed in a way that means that the structural elements not necessarily has a direct correlation to the aesthetic impression of the façade in its completed form. The cap is today primarily produced from aluminum, a material that with increasing success can be recycled, but that still has a profound negative effect on the total resource consumption and waste production in the building industry. One kilo of useable aluminum equals around 85 kilos of waste as well as heavy energy consumption in mining and handling. Recycled aluminum equals around 3.5 kg waste pr kilo.
Today, only limited alternatives are available that offers the precision in aluminum details. Energy, industry and material standards have over time created a one-sided materiality of the cap. This needs to be challenged and rethought through a circular perspective.
The massive spread of glass facades in the building industry since the 1970’ies means that the aluminum cap as a standardized aesthetic detail has a quite substantial impact on the visual experience of our buildings and cities. It is a detail found basically everywhere you see a glass façade and it is produced in enormous quantities. The cap is tailored to the technical system of each manufacturer and its degree of reuse is thus quite limited, unless as recycled raw material.
This means that a cap with a much better degree of reuse; a standardized system reaching across manufacturers - or best of all, a cap produced from a recycled or up-cycled material, will not only ensure a larger detail variation in the industry, it is also a building component that because of its total volume has a real potential to reduce waste in both production and in the building industry.
Performance and delivery
We have experienced ourselves some of the challenges of implementing reused and up-cycled elements in the building process. Among these challenges are the building codes of performance in materials, building components and its details, as well as to ensure that all materials are delivered at the right time and place in the process.
Not part of the façade mechanics or performance regarding cold, warmth or structure etc., the above makes the cap even further interesting as it is a product that does not have complex demands to its performance. At the same time, the cap is one of the components that is mounted towards the end of the building process, and can technically speaking be attached when the building is already in use. The infrastructure of delivery is thus not as crucial for the rest of the process as is the case for i.e. concrete elements or façade closure components.
Possible collaborations / development drivers
- Central façade manufacturers
- Early steps of production
- Alternative material manufacturers