Straw, clay and seaweed must be part of the future

LCA calculations were hardly part of the consideration when the folk fairy tale about The Three Little Pigs passed from mouth to mouth back in the day, nor when Walt Disney’s film adaptation hit the screen in 1933.

But when fast-forwarding to today, this classic example of childhood learning must be seen in a more varied context. You cannot just conclude that the cleverest pig was the one who used bricks rather than the two who used wood and straw.

On the contrary, biogenic materials are an inevitable ingredient in the green transition in construction.

This is of course somewhat exaggerated as the use of the materials requires a different kind of intelligence in order to achieve the right characteristics and qualities.

Artelia is part of the team that is helping the association Realdania assess how biogenic products can play a greater role in Danish constructions and contribute the best way possible to a reduced climate footprint – a question that contains many facets, and the analysis must also map the potential for growing the crops in Denmark.

Several different perspectives are necessary.The team includes Smith Innovation, JAJA Architects as well as researchers from Aarhus University, the University of Copenhagen, BUILD – Aalborg University and the Royal Danish Academy.

Nature’s own CO₂ capture
While the production of several conventional building materials emits large amounts of CO₂, biogenic products have an advantage, as plants absorb CO₂ from the atmosphere as part of photo­synthesis.

Furthermore, if we turn plant-based raw materials into building materials, carbon will be stored instead of being emitted by composting or burning.

This is a significant reason why timber has experienced a renaissance, and Artelia has helped set the agenda with several pioneering projects.

Timber is part of the solution, but the analysis will also look at other biogenic products, where the potential for significant CO₂ reductions is large and unrealised.

This applies particularly to fast-growing crops such as straw, grass and hemp, as they absorb CO₂ at a higher rate and grow anew every year.

If the climate footprint is to be reduced significantly, biogenic alternatives must be found for all building parts and not just for structures, says Artelia’s project manager Steffen Maagaard :

Clarification of needs at macro level
A first step in the analysis is to map the future need for building materials in Denmark and assess where it is an advantage to use bio-based products.

For this work, we will, among other things, draw on our self-developed LCA database, which is based partly on our own projects, but also on best practice cases from the Housing from 4 to 1 planet initiative and projects from Videncenter om Bygningers Klimapåvirkning (knowledge centre on buildings’ climate impact).

The complex question requires that we also take several different future scenarios into account, e.g. the expected degree of new construction versus renovation.

Another large part of our task will be extensive LCA calculations, which must map the CO₂ gain by choosing bio-based materials, with a special twist, says Steffen :

Hypothetical EPDs
In collaboration with the team’s experts, we must determine products that have the right qualities and the best conditions to be grown in Denmark.

Cultivation, accessibility, biological factors and material properties must therefore be examined.

With our knowledge of both life cycle analyses and construction technology, we will, among other things, contribute with a mapping of existing biogenic building materials and manufacturers on the European market.

From there, we will – together with BUILD – assess which resources have the greatest potential in a Danish context. Agronomists and other researchers from the University of Copenhagen and Aarhus University will then look at the other aspects of cultivation, biology and land management.

The major interdisciplinary effort will result in a net list of selected products that have the potential to be produced in Denmark in the near future and in the longer run.

Each product on the list will have a life cycle assessment, which must both include the potential benefits of local production and rest on a solid empirical basis.

It is therefore central to obtain detailed production data from established productions of biogenic building materials in both Denmark and abroad, says Steffen:

The structure catalogue
In order to support the journey from theory to practice, a structure catalogue will be prepared, which will be a list of pre-accepted solutions.

Based on the other analyses, the catalogue will demonstrate how the materials can be included in primary building parts when taking into account various performance criteria such as e.g. moisture, fire safety, energy and acoustics.

The purpose of the structure catalogue is to shed light on and demystify some of the uncertainties and concerns that may arise from the use of biogenic materials.

At the same time, the catalogue will have specific examples of construction principles that have already been examined and in some cases tested in relation to meeting common and relevant requirements for modern construction.

Here, we can draw on experiences from other projects such as Bio-based floor decks of the future, where several aspects were examined, including sound conditions that were tested in the acoustics laboratory in the Technical University of Denmark (DTU).

As part of the project Housing from 4 to 1 planet, we have also been involved in preparing fire safety schemes that highlight the possibilities for using bio-based materials with regard to the applicable fire safety requirements in Building Regulation 18 (BR18).

Helle Bugge, who is a certified fire consultant for third-party control, took part in the work, and she wants to help conclude the importance of innovation projects :