Not just home sweet home but a material bank

Polly Davis
Polly Davis
August 13, 2021
Circle House seen from the inside

It’s not often you hear architects talking about demolishing a building that they are designing. But that’s what happened during the planning phase of the social housing project, Circle house, in Lisbjerg. Because if you want to design according to the principles of circularity, you have to consider what happens to the building beyond its intended lifetime.

This social housing project has challenged the conventional “build, use and dispose” method of design, by using components that they can be easily taken apart. If you are familiar with children’s LEGO building blocks, circularity in construction uses a similar principle: build your structure, then take it apart to build something new. While it sounds simple, it hasn’t been without its challenges.

Materials as resources for reuse

First up – the components. Let’s take the example of the precast concrete panels that form the shell of Circle House. Normally, precast concrete is joined using casting assemblies between each panel. However, using casting assemblies makes it impossible to reuse the concrete. That’s why the concrete manufacturers created a new type of panel for Circle House that can be assembled using bolts. If the building needs to be taken apart, it’s simply unbolted and the panels can continue their life in a new building.

Disassembly and reuse of every single part of the building has had to be considered – from the walls, to the roof even down to the carpet. However, not all components have had to be redesigned. For example, ROCKWOOL stone wool insulation products are designed for long-lasting performance and are circular by nature. If disassembly takes place before the building is 50-years-old, the stone wool can simply be reused. Thereafter, the stone wool is fully recyclable and can be easily reprocessed to create new insulation materials for future buildings.

A different more circular look

Another challenge for the architects has been how to manage installations. In most modern housing, installations such as cabling and pipes are hidden in the walls. However, doing this in the Circle House would make the interior walls unsuitable for reuse. That’s why Circle House has visible installations. “Residents will experience a new type of architecture in Circle House,” says Anders Lendager, Partner in Circle House and Owner of Lendager Group. “Assemblies and installations are visible. They’ve been created to be aesthetic and part of the architecture.”

For the housing association, building circularity makes perfect sense. Firstly, the visible installations make maintenance and repair much simpler. What’s more, circular building construction creates a new level of flexibility to alter the building as needs change. If young families move out and the building is needed for students or single people, they can simply move walls, and create new sizes and types of housing. And they can do it without any of the cost, wastage or extra resources involved in demolition and a rebuild. Finally, and perhaps most importantly for a housing association looking to provide housing for those on modest incomes, Circle House demonstrates a more affordable way to build.

Cross-industry collaboration

The first Circle House is now a successful proof of concept. However, circular construction is still in its infancy and getting this far has been a great team effort – great in terms of both the efforts involved and the number of people. A total of 25 different parties, including the architects, circularity consultants, entrepreneurs, contractors, the municipality and component manufacturers, including ROCKWOOL, have spent hours meeting to discuss issues and questions that have never been considered before in construction projects.

The implications of moving circular mainstream

For example, who is responsible for guaranteeing the quality of the components when they are reused in another building? Would leasing make more sense instead of purchasing them outright – much as you would lease a car? How can circularity be part of the tender process? These are just some of the questions that need answering before circularity in construction can move mainstream and become part of tender bids, construction contracts and legislation.

Circle House has started these important discussions that need to continue if we are to bring much-needed circularity to the construction industry. And when you see how much waste the construction industry creates, you realise how important this is. According to Science Direct, as much as 30% of all building materials delivered to a typical construction site can end up as waste.

You don’t need to be an expert in sustainability to see that continuing with traditional construction methods is simply not sustainable for our planet. As we hurtle ever faster to irreversible climate damage, keeping building materials in use can contribute to achieving climate goals. With the pioneering Circle House building, circularity has taken another step forward to becoming a scalable feasible concept. There is still a long way to go. But this social housing project in Lisbjerg is showing that there is a way to build in a more sustainable manner: it’s circular.

According to the Ellen MacArthur Foundation, the circular economy is based on three principles 

1: Design out waste and pollution;

2: Keep products and materials in use;

3: Regenerate natural systems 


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