Material Health & The Material Rating System

What is Material Health and Why is It So Important?

Material health refers to the practice of understanding and evaluating the composition of products, specifically identifying the ingredients within them and assessing how those ingredients impact human health and the environment throughout their lifecycle. In the context of building materials, this means scrutinising the chemical makeup of products to identify and reduce the presence of hazardous substances, such as volatile organic compounds (VOCs), heavy metals, flame retardants, and other toxic chemicals. The goal is to prioritise transparency, safety, and sustainability in material selection.

Material health is critically important for several reasons. First, it directly affects indoor air quality—a major determinant of human health, given that most people spend up to 90% of their time indoors. Toxic materials can release harmful pollutants into the air, contributing to respiratory issues, allergies, and even long-term health conditions like cancer or neurological disorders. Second, material health has environmental implications. Materials containing hazardous substances can leach toxins into soil and water during manufacturing, use, or disposal, harming ecosystems and communities. Finally, by prioritising material health, the building industry can contribute to a broader cultural shift toward sustainability, innovation, and human-centric design, driving demand for safer, more eco-friendly products.

Understanding and prioritising material health is essential for creating spaces that not only meet performance and aesthetic goals but also safeguard the well-being of occupants and reduce the environmental footprint of construction practices. This approach reflects a holistic commitment to healthier, more sustainable living environments.

In Building Biology, we evaluate building materials based on their impact on the internal environment of a structure and their broader effect on the external environment, including production, availability, and usage. When selecting or recommending materials for a building, it is essential to consider their influence on both ecosystems. Naturally occurring materials are generally more advantageous for creating a healthy home compared to synthetic, energy-intensive alternatives. They are also more sustainable, durable, and have a lower environmental impact, making them a more cost-effective choice over time.

Building materials significantly affect interior climate factors such as air and surface temperatures, temperature gradients, moisture levels in both materials and air, air circulation, and natural ventilation. For these reasons, we must prioritise sourcing and using materials that enhance our living environment while reducing those that contribute to building-related problems.

Building materials should be assessed according to the following:

  • Thermal properties

  • Heat storage and thermal insulation = the equalisation of temperature

  • High surface temperature (especially floor temperature)

  • Properties with regard to humidity

  • Good hygroscopic potential for water vapour storage

  • The ability to increase and regulate room air humidity

  • No condensation

  • Electrically neutral (especially with regard to electrostatic charge)

  • Penetrable by air, (breathing active, continuous airing, filtration effect, similar to the human skin), and diffusible, (to cause gas exchange according to the concentration differences between internal and external air until a state of equilibrium is reached)

  • Capable of absorption, the chemical bonding and neutralisation of gaseous air pollutants has a buffer effect

  • Neutral in smell or with a pleasant odour with no toxic gas or vapour discharge

  • Little to no electrostatic charge

  • No electric conductivity especially with regard to the electromagnetic alternating fields

  • Radiations of cosmic and terrestrial microwaves remain unchanged

  • Micro-flora and micro-fauna favourable

The most important criteria of a building material or component from an ecological and health perspective are:

1. Natural occurrence

2. Ecological compatibility

3. Energy consumption

4. Thermal properties

5. Acoustic properties

6. Diffusion/breathing properties

7. Hygroscopicity

8. Toxic vapours and gasses

9. Electrical Properties and Radioactivity

10. Health impact

Using this approach, we can evaluate the suitability of materials for integration into existing buildings or, more importantly, recommend appropriate materials for new construction or the renovation of an existing structure. A key consideration is minimising "embodied energy"—the total energy and fuel consumed in sourcing raw materials, processing, transporting, and installing them, offset by the energy saved through reuse or recycling at the end of their lifecycle. This is most effectively achieved by prioritising locally sourced materials whenever possible.

Avoiding toxic materials—both natural and synthetic—that may pose health or environmental risks during production or construction is critical to ensuring the building’s occupants face fewer health concerns. Additionally, reducing reliance on scarce, non-renewable resources and minimising contributions to environmental pollution can be achieved by incorporating alternative, renewable energy sources and maximising the use of solar design. Such practices promote the creation of buildings that support both human health and a sustainable, liveable planet.