KULeuven Living Lab

General information

This living lab is being built on the grounds of the Ghent Technology Campus (KU Leuven) and is a test building with a terraced house typology. The prototype will be later used in urban renewal projects in deprived neighbourhoods. This includes not only group housing construction and renovation, but also roof extensions and facade renovations. The living lab has been designed so that all these scenarios are technically possible. It has also been designed so that construction companies can get involved in the social economy during construction, and so that it can be easily moved to other parts of the city. The latter is also a requirement of the prototype because in 2027 it will have to make way for the campus’s new master plan. This will be the ultimate test for the portable bio-based living lab. Look at the video or visit the lab virtually!

Change-oriented design
Design for reuse and recycling
Integrating recycled and reclaimed elements
Preparing the material bank of the future
Waste during the construction phase
Focus on maintenance
Aiming for low environmental impact
Sharing and managing information
Innovative businessmodels and construction processes

Change-oriented design

The KU Leuven Living Lab concept focuses on terraced housing, facilitates flexible use, and anticipates densification strategies for future urban renewal. The living lab is built from standardised modular components based on a 60cm grid.

In the middle of the house there is a CLT stairwell to give the house lateral stiffness, which means that the front and rear facades are non-load-bearing. The floors are load-bearing from one party wall to the other. The inner walls are therefore also non-load-bearing. As a result, if the family composition were to change, the interior walls can be easily adapted in all sorts of ways. In the event of volume extensions (e.g. on the ground floor into the garden), the rear facade can be removed without extra work needed for stability. The entire structure, including foundations, can accommodate 5 floors.

If there is a change in function (cross-functional flexibility), the front facade can be redesigned (e.g. a large window added to create a shopfront) without extra work needed for stability, and both the stairwell and the intermediate floors already have fire compartments.

In terms of technical installations, oversizing and integration into other floors were taken into account. All production and storage components are calculated for a 250m² house. In addition, all areas are relatively quickly accessible and adaptably integrated into the subfloors, which can be detached, and into the central technical shaft. This means the finishing materials will not get damaged during changes.

The completed Flexibility-Calculator for this Living Lab can be found here. It was assumed that the building will be relocated after six years because it can no longer remain on the KU Leuven Campus in Ghent. In the process, it will change location and function (from office to residential). The investment to make the building remountable has been divided by two as this inevstement also has an end-of-life benefit. This has been calculated in the end-of-life calculator. The building consortium plans to produce the Living Lab on a large scale. The expectation here is that this will also lower the additional investment for remontability than can be found in the pre-completed calculator.

Design for reuse and recycling

This living lab concept was conceived as a ‘material bank’. Specifically, the test house that was built on campus will be disassembled at a later date (end of first life) and then rebuilt somewhere in an urban environment. It is possible that the disassembled modules will be rebuilt based on a floor plan with different dimensions than the ‘campus design’. Thanks to the modularity and specific connection methods of the components, the test house can be configured in different ways and adapted to the second construction site.

This was made technically possible by building in a way that allows for complete disassembly. All connections in the building are reversible. As reuse is considered at the component level, the intrinsic residual value of the ‘yield’ is high relative to the cost of recovering it, which makes for a favourable business case.

For example, the facade panels are prefabricated boxes filled with cellulose insulation. In addition, they are reversibly connected to each other and to the adjacent floor or roof modules. Interior and exterior finishes were also added in a reversible way. The technical elements only run in the subfloor, between the beam grids, or in inner walls and therefore not in the outer facade elements. At the end of life, everything can be disassembled and the facade elements can either be refurbished (new insulation) or simply reused in a new home.

In terms of technical installations, reuse potential was also factored in. The specific integration into the building enables the recovery of all components without damage. Thanks to reversible connections between pipes and other components (e.g. taps, pumps, etc.), even more functional components can be ‘yielded’. The Litobox as a whole will be refurbished as a product and reused in a new lease contract.

The end-of-life calculator for the KU Leuven Living Lab with pre-filled values can be downloaded here. It has been estimated that the building will last 60 years and that the materials will eventually yield around €40,000. The investment to easily dismantle the building at the end of its life has been divided by two as this investment also has a flexibility benefit. This has been calculated in the flexibility calculator. The construction consortium plans to produce this building on a large scale. It is expected that the additional investment for remontability will therefore be lower than found in this pre-completed calculator.

Integrating recycled and reclaimed materials

In the KU Leuven Living Lab, the tender documents stipulated that a certain percentage of the material used in the building had to come from reuse or refurbishment. For example, the two Velux windows were purchased from Carré Dakramen, a reused skylights dealer listed in Opalis. In addition, the interior doors, kitchen and furniture were purchased from Labeur en Scrap vzw, also traders and processors of reused materials. The building’s grid thresholds came from an old building site container belonging to the contractor. The tiles used for the front and rear facades and the roof were supplied by Wienerberger at a reduced price because the tiles contained manufacturing defects (colour shading). In other words, using the tiles in the living lab prevented them from ending up in a downcycling process or even in landfill. Finally, all cellulose insulation is made from recycled paper.

Preparing the material bank of the future

The entire living lab was modelled in BIM. The final as-built model was delivered and made centrally accessible to all parties involved. During its lifespan, it will be used to document the current location and ownership of the measuring and technical equipment (as per the leasing contract). In addition, at end of life it will be used to ensure that the disassembly and resulting yield of materials run smoothly. Technically, no material passports were made, but all the components in the model contain all necessary information regarding material properties and quantities. Finally, special attention was given to a standardised coding system (SfB/NL) for all components.

Waste during the construction phase

A large part of the building was prefabricated. Extensive standardisation in dimensions meant that there were virtually no offcuts. By using base material on coils, only 0.4% of the material was wasted during the production of the steel profiles for the walls, floors and roofs. This means that no waste is produced when the structure is assembled on site. The quantities are bigger for finishing materials, but because only dry methods were used, this is kept to a minimum.

Focus on maintenance

The performance of the technical installations in the building is continuously monitored by an OpenMotics monitoring module. Based on the stored data, this module can proactively trigger a maintenance action before a defect occurs. For example, the consumption of a fan steadily increases the closer it gets to the end of its usual lifespan. The fan is then replaced just before it fails, ensuring continuous operation.

There is no digitised follow-up for the maintenance of the structure and the shell. Therefore, traditional follow-up is required here.

Aiming for low environmental impact

Eco-conscious material choices:

Reuse via urban mining (10%)
Bio-based materials (75%)

Calculations (LCA):

The LCA calculations were carried out in this project in three different ways. Firstly, 9 different construction methods were applied to the geometry of the building in the preliminary design phase. This gave insight into the environmental performance of individual components in relation to the entire building. A comparative study between two alternatives for a certain application or the entire building as such is relevant, but so is the share of certain components in the bigger picture of total environmental cost. Secondly, during the development phase of the final concept, smaller studies were used to include environmental impact as a criterion in the decision-making process between e.g. two alternatives for a particular application (e.g. glass granulate vs seashell case as foundations). Thirdly, at the end of the project, an LCA study was carried out to compare the building in terms of environmental impact with buildings of a similar size and function.

Sharing and managing information

The entire living lab was modelled in BIM. The final as-built model was delivered and made centrally accessible to all parties involved. During its lifespan, it will be used to document the location and current ownership of the measuring and technical equipment (as per the leasing contract). In addition, at end of life it will be used to ensure that the disassembly and possible yield of materials run smoothly. Technically, no material passports were made, but all the components in the model contain all necessary information regarding material properties and quantities. Finally, special attention was given to a standardised coding system (SfB/NL) for all components.

De prestaties van de technische installaties in het gebouw worden permanent gemonitord door een monitoring module van OpenMotics. Deze module kan op basis van de opgeslagen data proactief een onderhoudsactie triggeren voordat een defect optreedt. Zo loopt het verbruik van een ventilator bijvoorbeeld gestaag op naarmate de gebruikelijke levensduur dichter bij zijn einde komt. De ventilator wordt dan vervangen net voordat hij faalt, waardoor een continue werking gegarandeerd blijft.

Innovative business models and construction processes

The access model provides product access instead of ownership and is therefore dependent on service level agreements. In the construction sector, access models are usually used for service-dependent products such as lighting, climate control and lifts. Experimental projects involve the ‘leasing’ of building components with a long lifespan, such as facades. The interviews, case studies and especially the calculators developed by the CBCI have shown that service models are best applied for building layers (shearing layers) with a limited lifespan. More specifically, the layers, the space plan and the technical installations. The uncertainty of cash flow calculations only increases the longer the term being considered. In addition, the circular added value, e.g. by residual value at EoL, becomes insignificantly small by discounting due to the current net worth methodology.

The performance model delivers product performance rather than the product itself. In the construction sector, the example of ‘pay per lux’ (a joint concept from Philips and Turntoo) is often used. The physical products are robust, sustainable and easy to maintain, meaning that revenues increase the longer the products last. This model relates to the substantiation of the costs for the user in a fixed fee and for the provider in the form of a fixed cash inflow.

In the case of the living lab concept, an access model was also applied, although this does require some additional explanation. The contract stipulates that the technical installations remain the property of the lessor and are therefore activated in their accounts. The transaction is regarded as a lease on the part of the tenant (KU Leuven). The entire transaction remains off the balance sheet of the lessee. Strictly speaking, however, this is not sufficient for circumventing the principle of acquisition of ownership by incorporation, a difficulty which was not addressed at the time of the conclusion of the lease.

So it is clear that not the components themselves, but their use was contracted. In addition, the tender did not prescribe specific installations, but the performance they had to deliver. This was done by setting applicable standards, the usual best practices and the BEN label (BEN stands for “Bijna Energie-Neutrale Woningen”, which means “Nearly Energy Neutral Homes”) as the standard for the performance level in terms of energy efficiency. This performance is made possible by design considerations (thermal performance of the building skin, airtightness, etc. tailored to the properties of the chosen installation components) and by enabling data-based maintenance and replacement of components during the use phase via the OpenMotics software and data collection.