Climate change has been on everyone’s lips for some time. It is clear that measures must be taken to slow down global warming. An important part of the change must happen in the building industry, because it has a direct impact on our environment.
In Switzerland, over 7 million tons of energy are used each year just for building material. There is still a lot of room for improvement. Therefore, we have set ourselves the goal to investigate this part of the building industry with our project. In cooperation with an expert, we have clarified the question: Which building material is optimal for the climate and the environment.
After narrowing down the building materials we were investigating, we had to find a way to evaluate these building materials in a meaningful way. First, we tried to find important criteria for environmental impact. We found some, but few have the possibility to be measured in a meaningful way.
Through the exchange with our expert, we decided to limit ourselves to the so-called “UBP”. “UBP” (german for Umweltbelastungspunkte: wikipedia.org) stands for environmental impact points. With this number it is possible to compare building materials.
The UBP measures the environmental impact of different building materials. The UBP contains the impact of the consumed energy and material resources, of land and water, of emissions to air, water and soil, and of the deposition of residues from waste disposal and traffic noise. In addition, the recycling of the substance is also taken into account in this figure. The advantage of this method is that it assigns a meaningful weighting to all the points mentioned, which makes the figure very informative.
According to our research for the project, we compiled a list of materials that we wanted to compare. However, through consultation with an expert, it became apparent that certain materials were unsuitable for our comparison methods. So, in cooperation with the expert, we limited ourselves to the following materials:
Consumes very little primary energy in extraction and transportation. It is also easily reused after demolition. 
requires time-consuming and precise preparation, but they are versatile. However, it is very static, so it can quickly crack. 
are easy to apply and provide good protection against fires and water. That is why this building material was often used in industrial buildings. 
Conrete is the most popular building material of modern times. It is ideally suited for residential builidings due to its good sound insulation and fire protection. However, conrete is susceptible to mold in case of insufficient ventilation. 
is a special building material. It does not have the robust properties of the other materials, but it is visually appealing. A big disadvantage is the permerability. In summer, a lot of heat is let in, and in winter you lose heat. 
Now we come to the results from our project. First, we compared the green house gas emissions of the building materials. These already give an informative picture of the environmental impact of different building materials. It is important to emphasise that the Greenhouse gas emissions are included in the eco-points.
It is important to mention that it is not possible to compare different building materials per se. Depending on the building project, there are other possibilities with regard to the environment. However, the UBP comparison can be used as a guideline to evaluate building materials in general.
If we now look at the diagram with the UBP comparison, a very similar picture emerges. The more natural the building materials are, the more environmentally friendly they are. A particularly good example is rammed earth. Rammed earth was used as a building material early on because its extraction is very simple and requires very little energy.
If you compare the very popular building material concrete with rammed earth, you can really see the extent of this. As an example, we took the UBP of one ton. We came to the conclusion that if rammed earth is used instead of concrete for a building, the saved UBP can be used to travel from Zurich to Geneva 30 times by train.
1000 kg of concrete correspond to 348,000 UBP whereas 1000 kg of rammed earth correspond to only 39,400 UBP. The difference of 308’600 corresponds to a journey of about 7’400 kilometres by train (1000 UBP are 24 kilometres). The rail distance between Zurich and Geneva is 224 kilometres (7400 kilometres divided by 224 kilometres equals 30 times the length of the line).
Considering our results, we recommend using building materials that are as natural as possible. We know that each building project has to be considered individually to take into account factors such as location, budget, temperature, preferences, etc. Therefore, for practical reasons, materials such as concrete are often used. However, we recommend that one should always consider whether it is possible to use natural materials. Not only do they help to protect our environment, but they also offer a pleasant change from conventional materials.
During this project we learned a lot about the importance of building materials. They have a big impact on the buildings but also on the environment. Our calculations showed that flat glass has the worst influence to the environment considering manufacturing and disposal. By using other building materials we can safe masses of energy for other things.
We also realised how difficult it is to make environmentally friendly adjustments, as there are many individual variables in a building project. However, we are convinced that in the future, more use will be made of environmentally friendly materials such as rammed earth, and thus great savings can be made.
Authors: Justin Valiyaveettil, Dario Di Fazio
 Building Material Energy Consumption (empa.ch)
 Rammed Earth (wikipedia.org)
 Cement Stone (cdn.net)
 Bricks (immodirekt.at)
 Concrete (allplan.com)
 Flat Glass (wohnsauber.com)
 Life cycle assessment (kbob.admin.ch)
 meaning of UBP (carbotech.ch)
Rammed Earth (rammedearthartisan.com)