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Klassenhäuser: façade



Comparing wooden and brickwork facades of identical buildings

Innovative solution

Otto Wulff / Ehoch3 / Hamburg University of Technology

Partners Involved

School buildings

Building type

(Prefabricated) Concrete, steel

Structural material

Structural system

Curtain wall system


This demonstrator builds on the previous one but looks at the façade systems instead of the slab construction to improve the circularity of school construction in Hamburg as part of the Klassenhäuser project.


The aim was to investigate the reusability of façade elements and construction approaches to allow for dismantling façade cladding without damaging the materials. Two real projects where used for this demonstrator – one representing the BAU case and one a more innovative approach to increase circularity.


The studied façade system was a prefabricated concrete façade where the BAU had a brick cladding with concrete mortar cast to the concrete panel, and the demonstrator alternative a timber cladding on timber studs attached the concrete system.

Demonstrated innovation

By identifying façade elements that are suitable for reuse or recycling, the environmental and financial impact of façade claddings can be significantly reduced.


In the BAU case, the cladding material (brick) is case together with the structural and insulation element of the façade system. This makes it very difficult to recover the materials without damage to the individual components. It also results in a high amount of mixed waste during demolitions.


In contrast, the proposed solution of the timber façade separated the cladding from the insulation and structural system. Each building element can therefore be disassembled separately, with minimal damage to the different components, resulting in high reuse potential and greater opportunity for recycling.

Activities done

  • Different façade elements were examined on two different but identically constructed buildings. The façade elements investigated consisted of brickwork and wooden elements. 

  • A complete BIM model of the construction methods was created to investigate the effects and quantity changes of the building materials. 

  • The digital model was analysed with BIM quantity take-offs and can be used for visualisation and representation of the differences and used building materials. 

The building components were evaluated according to the possibility of dismantling and reusability. Possible constructive improvements to increase the demountability and the associated possible reusability were identified. 

Demonstrated impacts

Compared to brick facades, pre-hung wood facades can be easily removed due to their screwed assembly and can therefore be reused to a greater extent. This results in a façade system which can be completed reassembled.


Furthermore, timber has much lower density and embodied carbon compared to bricks. Already in the first iteration of a façade system there is significant savings from choosing timber over brick from an embodied carbon perspective. This saving will only become greater as the building or façade would need replacement and the timber façade potentially could be disassembled and reused again, whilst the brick façade would require demolition and rebuild.

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