The Construction Material Pyramid – A Brief Explanation

In Denmark, everyone knows the food pyramid. It tells us about the relationship between our food intake and our health. What we can eat in large quantities and what should we eat less of.

Based on the food pyramid’s graphical language, we at the Centre for Industrialised Architecture (CINARK) at the Royal Danish Academy have developed a digital version of the Construction Material Pyramid, which we published as a poster in 2019.

The digital version of the Construction Material Pyramid makes it possible to compare, for example, CO2 footprints between different categories of materials or between material types within the same category. It also makes it possible to view different kinds of environmental impacts across the different materials. It thus offers a tangible, interactive calculation tool and at the same time opens up a dialogue about more detailed studies of the materials’ position in the pyramid and later their place in the project design. The goal is that it provides a simple way to gain a quick overview of the relative sustainability of the individual building materials.

Based on Environmental Product Declarations (EPD), the Construction Material Pyramid shows the environmental impact of a number of relevant building materials. Here, we have chosen to focus on the initial phases of construction, i.e. until the material is on site (life cycle phases A1–A3).

In other words, the Construction Material Pyramid is a way of visualising the environmental impact associated with the production of materials. The service life of the material can then be handled as a technical design parameter, where work is carried out on the details of the construction in relation to how long the building should last.

In this context, it is the responsibility of architects to ensure that the materials’ service life does not depend on the overall composition of the building component and therefore defined by the worst-executed material or construction. It has thus been the ambition to bypass the problematic standard assumptions that govern the outcome of life cycle assessments (LCA).

We have received many positive and curious enquiries from ordinary craftsmen to teachers at vocational schools, practicing architects and lay people. We believe that the Construction Material Pyramid, like the food pyramid, can be a crucial guideline and educational guide for all when they have to make the right environmental choices when doing business in the construction market, buying a house, rebuilding, or just wanting more knowledge about the field.

The target group is project architects, designers, and consultants, as well as students in educations aimed at construction. In addition, the digital version of the Construction Material Pyramid can be used for wider dissemination to developers and for information campaigns as part of the construction industry’s green transition.

The project group behind the digitised material pyramid are senior and junior researchers at CINARK, as well as Jan Schipull Kauschen from Vandkunsten. The project is financed with support from Boligfonden Kuben.



Environmental Impact Categories Used in the Pyramid
Potential damage to the environment, ecosystems, and health can be mapped when performing so-called life cycle assessments (LCAs). Since the type and dimension of the potential damage are fundamentally different, methods have been developed for the calculation of damage in environmental impact categories. There are a large number of environmental impact categories in addition to the five used in the pyramid, which are, however, the most common in building-related LCAs. The categories relevant for the construction industry are specified in the European standard CEN/TC350.

Global warming Potential (GWP):
Global warming is caused by greenhouse gases, including the chemical substance CO2. GWP is calculated in CO2 equivalents (CO2eq), which means that CO2 is used as a reference substance and indicator unit. The use of “equivalents” is common to all environmental impacts, in that there are many different substances that can cause the same damage to the environment, ecosystems, or health, but in different orders of magnitude. For example, 1 kg of methane causes the same potential damage as approximately 25 kg of CO2 when emitted into the atmosphere. GWP is also what is referred to as the “carbon footprint” in connection with products.

Ozone Depletion Potential (ODP):
ODP is the depletion potential of the ozone layer. Thus, this includes the chemical compounds that have an effect on the depletion of the ozone layer. Degradation of the ozone layer means that the intensity of UV radiation increases and therefore damages plants and animal species. As an indicator unit for ODP, equivalents of the chemical substance freon (R-11eq) are used.

Photochemical Ozone Creation Potentials (POCP):
Under this category, the formation of photochemical smog is described. In high concentrations, ozone can affect the health of both humans and nature, and can especially affect breathing. POCP is measured using ethylene equivalents (C2H4eq) as an indicator unit. The environmental impact stems in large part from volatile organic compounds (VOCs), which can occur in the production and incineration of plastics and paints.

Acidification Potential (AP):
AP describes potential influences of acids that are emitted into the atmosphere in a gaseous form or in the soil and water as a substance. Acidification can cause damage to the ecosystem and especially plants. In the 1980s, there was often talk of “acid rain”. This impact category is measured using the indicator unit sulphur dioxide equivalents (SO2 eq).

Eutrophication Potential (EP):
EP denotes an excessive load of nutrients that can potentially harm the environment. Over-fertilisation of the soil can affect the vegetation and eventually result in its death; the environmental impact is also called “desertification”. Over-fertilisation can also have the opposite effect, creating optimal conditions for plant growth so that it ends up with the plants outcompeting other living organisms. This can happen, for example, in oceans and lakes, where it can result in algae growth, which can damage the biodiversity. EP has phosphate as reference substance and is calculated in phosphate equivalents (PO4eq).

You can read more about environmental impacts and LCA within the construction industry in SBi/BUILD’s report “Bygningens Livscyklus” [The Building’s Life Cycle] (SBI2015:09) and the report “Klimapåvirkning fra 60 bygninger” [Climate Impact from 60 Buildings] (SBI2020:04).
Also, you can read about how we have tested the ideas behind the Construction Material Pyramid in the book: “Circular Construction – Architecture, Materials, Tectonics” (CINARK2019)


Data Used
Data used in the pyramid comes from publicly available EPDs that material producers, material suppliers, or industry organisations are normally responsible for. EPD stands for “Environmental Product Declaration” and is thus a product declaration that describes the material or product’s potential environmental impacts. The actual process for creating EPDs is standardised, and LCA specialists are able to produce them.
EPDs are often made available in databases or via manufacturers’ websites, and this is also where we have gathered them from for our project. EPDs from Denmark have been used as far as possible; in addition, the German database Ökobau.dat has been used, as well as EPD’s from the Norwegian EPD Foundation, which has an extensive register of EPDs for building materials and products.
By “double-clicking” on a material, all the data we have used is displayed in detail, including a link to the EPD or the database for the LCA dataset, as well as the date of the data’s validity.


Life Cycle Phases A1–A3
From the EPDs, we have used data for life cycle phases A1 to A3 (cf. EN15978); this corresponds to material extraction up to production (“cradle-to-gate”). All further phases that occur in a life cycle analysis are excluded, including transport to the construction site and installation (A4/5), use and replacement (B4/6), disposal (C3/4), and potential recycling (D). The reason for this is that the material pyramid is not a tool for calculating LCAs, and all phases in addition to A1–A3 depend on the individual project and assessment made. For this, professional software such as BUILD’s LCAByg (www.lcabyg.dk) must be used.
The reporting and updating of life cycle phases A1–A3 is the manufacturer’s responsibility, cf. the standard. Good data is thus ensured, and potential uncertainties that must be dealt with in an LCA are therefore not relevant for figures given in the material pyramid.


Selection of Materials
The selection of materials for the pyramid has been based on a number of interviews with professionals in construction, which has resulted in a list of the materials used most in Danish construction. Attempts have also been made to keep the materials at a generic level so as not to single out a specific product within a material group. It is clear that there can be large variations in the materials’ environmental impacts depending on who the producers are and/or where and how the product is manufactured. To deal with this, data has been used from materials and products that have a large market share for the given type of material. If possible, we have used “industry data”, i.e. information provided by industry associations.

Unfortunately, we cannot guarantee the accuracy of the data used or the data that is referred to, and we do not assume any responsibility for any errors or omissions on the website.


If You Want to Contribute
The digital version of the material pyramid is flexible and will change over time. We would like to add more materials, and there are many ideas on the drawing board for more layers and more features. If you would like to support the project in one form or another, we are happy to receive an e-mail from you!
If you have a material that you think is missing from the pyramid, feel free to send us an EPD and, if possible, a material sample so that we can take pictures of it. If you have other good ideas or would like to use the pyramid in a school project, then please write to us at: info@materialepyramiden.dk


Have Fun with the Construction Material Pyramid!