Buildings have a significant impact on the environment, climate, and the quality of life. Until now, sustainable construction in the German context has been focused on use of natural, resource-saving or renewable building materials. In addition, through better insulation and energy-saving interventions there is an attempt to reduce the energy consumption during the operation phase.
The energy we use is increasingly derived from infinite energy sources, such as the sun and wind. The environmental costs during the operation phase are merely 15% of the total environmental costs of a building.
On average, about 85% of a building's environmental costs is related to the use of materials. This shift came about in the 1990s, and a logical consequence was the increased impact of material use.
The CLB Berlin and Architekturgalerie München invited Superuse to contribute to an exhibition that will stimulate the discussion about reuse in Germany by presenting the Superuse approach of reusing building materials by showcasing circular building strategies, tools and projects.
The exhibition has been partly funded by the Creative Industries Fund NL, due to Covid restrictions the physical exhibitions still have to take place, the content that was developed is integrated in and made accessible through the website of Superuse.
In comparison to conventional architectural design practice a few extra steps are added in the design process.
Most projects start with investigating the different relevant flows in a Material Flow Analysis. Important layers are: existing location, context, energy sources, water, food systems, existing built structures, natural structures, climate, materials, functionality, ergonomics, available budget, capacity of the project team.
After mapping those layers we search for possible interconnections. Ultimately this leads to a design that integrates all the relevant aspects.
Superuse calls searching, finding and dismantling reusable building materials 'harvesting'. For this purpose, Superuse founded the platform oogstkaart.nl in 2012. This marketplace for reusable building materials is used by Superuse as well as other architects, design professionals, builders and project developers. In 2019, the platform was sold to the urban mining company New Horizon.
When materials for a structure can be harvested, Superuse prefers to search as locally as possible. If a demolition or a renovation of an existing building takes place on the site of the design commision then logically this site is the first source to harvest materials. Afterwards, sources are sought in the vicinity of the project, whereby the scale can be increased if necessary.
There are various sources of residual materials, each with its own characteristics and dynamics:
_ End of life cycle (waste)
_ Construction and demolition (waste)
_ Dead stock (new)
_ Production waste (new)
_ Fast-life (short use)
When completing a design, Superuse often produces a graphic harvest map for the client with an overview of the residual materials used in the project and their original locations. In this exhibition, a project harvest map of each design is also shown.
For the project Buitenplaats Brienenoord materials were harvested both from the site itself as well from other locations. 90% of the materials used came from the former scouting building, among other components, the foundation, trusses, window frames and woodwork. The remaining materials were harvested from different locations, for example the ceiling tiles’ origin was 2.5km, while Trespa sheets came from another site 140km away.
Demolishing a building costs a lot of energy, therefore the strategy of Superuse is to reuse an entire building wherever possible. Here, we do not mean only renovating, but rather working towards a complete change of function and with the preservation of as many valuable parts of the old building as possible.
The supporting structure is always the departure point. Within the preconditions of load-bearing capacity and dimensions, we look for the optimal layout for the required programme. Where necessary, we create openings for the benefit of routing or add floors if the height allows. Often, a new entrance provides better relationships between the functions and creates a place that in turn provides an identity to the new use of the building.
We keep all installations for heating and electricity separate from other built-in parts according to the layer model of Stewart Brand, allowing easy maintenance and future changes. By thinking in terms of layers with different lifespans, we literally create a layered building. The readability of the functions is enhanced, since by making the technology and the supporting structure visible, the flows (power lines, electricity, water) become more legible. If necessary, different climate zones can contribute to strategic insulation interventions rather than insulating the building entirely.
In Art Zaanstad it is easy to see how the column structure has determined the layout of the space and the size of the moveable exhibition walls. The colour scheme of the walls and structure has been keptand expanded with a subtle palette of mainly black and white tones. The new entrance provides a clear public entrance.
Superuse uses a decision tree to make the hierarchy of material choices clear.
Preventing the use of a building component or material saves the most CO2 emissions and reduces the environmental impact.
_1 Reusable materials
With reuse, an existing building component is reused, whether or not for the same purpose, treated or untreated.
_2 Renewable / biobased materials
Materials that are derived from biomass. They can be physically, chemically or biologically treated. Ecological building materials are renewable without chemical or abiotic substances.
_3 Recycled materials
Materials that consist mainly of recycled raw materials.
_4 Conventional materials
When none of the options above are available, conventional building materials are chosen. These have no savings in terms of CO2 emissions or environmental impact. However, some conventional materials can be reused or recycled.
Superuse prefers to work with locally harvested reusable building materials. This is where the largest environmental gains can be made. Reuse prevents the production of new building material so pollution by recycling or burning waste decreases. Moreover, transport and related emissions are minimal.
In some cases, other materials can have a lower impact. For example, when reusable materials have to come from far away, or if additional processing or maintenance is required. This also happens when the reusable materials are outdated and do not contribute to the energy performance of a building (e.g. single glazing).
Circular building requires an integral approach throughout all phases, from initiative to realisation. The design plays an important role and Superuse, as architect, forms a design team with partners and the client to work in close collaboration towards a Dynamic Final Design. Next to conventional drawings, the design includes a harvest map that shows the origin of the materials and a dynamic list of materials that dissects the design into architectural components.
The dynamic list of materials provides insight into the ambitions formulated by the client and architect and the preconditions from the brief in all phases of the process. In addition to costs, the ecological footprint in CO2eq, for example, is a possible steering tool, or the percentage of bio-based material that will be used.
The project's harvest map consists of all sources known to us and in order to select the materials we use a decision tree that assists in limiting CO2 emissions. The preference is to work with reused materials, where available and applicable.
Ultimately, we hand over the design with the list of materials to the contractor as a shopping list. Based on this list, the design and a purchasing list are formed in order to achieve a circular realisation. If possible, this will be done in a construction team, in which the client, architect and contractor work closely together.
After project completion, all applied materials are bundled into a material passport. This is a digital representation of dynamic elements, which ultimately can be traced back to raw material level. During its lifespan, the passport helps with decision-making relating to the building's maintenance. In 50+ years, it can serve as a source for the supply of reusable materials.
Demountable construction occupies an important place within the circular construction methodology. This is also referred to as detachability. Materials can then be reused not just once, but continuously. Therefore, it is important that buildings and building elements are designed and built in a way that allows them to be detached. Superuse therefore designs 'dry' connections when possible. In other words, with demountable connections that ensure that materials and building elements can become available without any damage during maintenance or at the end of their lifespan.
Superuse applied this strategy in various ways in the design of the KEVN pavilion.
_ The pavilion is not built on a pile foundation. Instead, there are three layers of stelcon plates in the floor to create the necessary weight. Between are steel profiles, to which the trusses are bolted. The insulation layer lies between these, as does a layer of sand.
_ The main load-bearing structure made of trusses and beams is fully bolted.
_ A non-load-bearing curtain wall system of glass and steel is chosen for the façade. The glass can be clamped with click strips. The use of rubbers and profiles means that no gluing or sealing is required.
_The roof package is laid 'loosely', except for the water-retaining layer. This is glued on, but can be removed for separate recycling.
_ All installations for heating and electricity are kept separate from other built-in parts.
As a result, the KEVN pavilion is designed as a kit that can be easily disassembled and reassembled elsewhere. The materials retain their value and it is better for the environment.
In Material Driven Design, the architect is inspired and guided by available reusable materials. We assume high-quality reuse.
This means that the material can be used again in its original function or in a higher one without much processing.
In the concept or sketch design phase, the reusable material with its characteristic properties (such as size, shape, colour, weather resistance, durability) serves as inspiration. Sometimes the actual material is known while in other times Superuse works with materials that are expected to become available based on experience. In the latter case, the search for available reusable materials starts once a preliminary design is drawn. A final detailed design follows after certainty regarding the purchase of reusable materials. Modifications of the design must be possible up to the final phase. For that reason, Superuse speaks of a Dynamic Final Design. This is only possible with good cooperation between architect, contractor and client. If the search for specific suitable used materials begins after the design is fixed, the chance of success is smaller.
The Blade Made projects by Superuse are a good example of Material Driven Design. The characteristics of wind turbine blades are optimally utilised by the newly chosen applications. The shape of the blades lends itself for an ergonomic seating object as applied in REwind and Wikado. The shape of the blades also allows, after a few simple interventions, to create very diverse and imaginative play elements for children to climb on or crawl into. The material of the blades is robust, weatherproof and vandal-proof, ideal for a playground or outdoor furniture.
Currently, there are few suppliers who offer guarantees on reused materials. Therefore, other constructions have to be devised in order to retain the trust of clients. Depending on the scale of the project, a certain strategy can be adopted.
_ Shared responsibility;
In a building team of architect, contractor and client, the materials to be used can be agreed upon during a construction meeting. If together they have enough expertise to approve the materials, they share the responsibility. For some materials, common sense is enough to guarantee safe and sustainable application.
_ Buy off through external assessment;
In the event that common sense or joint expertise is insufficient to approve a material, it can be subjected to a test by a certifying body. This can be used, for example, to obtain a fire safety certificate or a declaration of equivalence, whereby the application is assessed by an external party.
For materials that are sensitive to wear and tear or the possibility of damage, it can be useful to keep a small stock of spare parts in the building. Examples of this are façade finishes or special glass sizes.
At Villa Welpeloo, all of the above strategies have been used. Recycled steel from the textile industry was used in the construction. Calculations made by a structural engineer showed that the lowest quality steel from the year the textile machine was built was strong enough to support the building. Extra slats of wood were purchased for the façade, should maintenance be required due to damage.
Texts by Superuse;
Jos de Krieger, Karola van Rooyen, Lizanne Dirkx, Frank Feder (ff-arch.eu)
Allard van der Hoek, Denis Guzzo, Frank Hanswijk, various Superusers
Grafisch Lyceum Rotterdam, Bas Schellekens
Special thanks to;
Creative Industries Funds NL, Sally Below (sbca Berlin), Nicola Borgmann (Architekturgalerie München), Beate Engelhorn (Haus der Architektur, Graz)