Sustainable materials are materials that deliver the function a design needs with lower environmental and social impact across their whole life, from sourcing and manufacture to use, reuse and disposal. The topic gained urgency in August 2025, when negotiators meeting in Geneva to draft a global plastics treaty ended ten days of talks without agreement, leaving designers to make many of the decisions on their own.
Key takeaways
- Sustainable materials are judged over their full life cycle: source, manufacture, use, reuse and end of life.
- The second part of the fifth negotiating session for a global plastics treaty ran from 5 to 15 August 2025 in Geneva and adjourned without a consensus text.
- Humanity produces around 460 million tonnes of plastic a year, according to the UN Environment Programme, and the figure could triple by 2060 without action.
- Because no binding global rule exists yet, material choices made at design stage are the most effective control on waste.
- Ask suppliers for evidence, such as environmental product declarations, and prefer materials that can be reused or recycled.
What counts as sustainable materials?
No single list can label a material sustainable in every case, because the answer depends on how it is made, where it comes from, how long it lasts and what happens afterwards. Designers usually test materials against six questions:
- Is the source renewable, reclaimed or recycled?
- How much carbon and energy went into making and moving it?
- Will it last, or can it be repaired and maintained easily?
- Can it be taken apart, reused or recycled at the end of its life?
- Does it contain chemicals of concern that harm people or ecosystems?
- Was it sourced responsibly, with fair labour and protection of habitats?
A material that scores well on several questions is a good candidate. These are the same criteria discussed in our article on what makes a product sustainable, and they apply to sustainable materials in architecture just as they do to consumer goods.
What happened at the Geneva plastics treaty talks?
The scale of the problem explains the stakes: humanity produces around 460 million tonnes of plastic a year, and the figure could triple by 2060 without action.
The second part of the fifth session of the Intergovernmental Negotiating Committee, known as INC-5.2, took place at the Palais des Nations in Geneva from 5 to 15 August 2025. After ten days, the committee adjourned early on 15 August without agreeing a treaty text. According to the UN Environment Programme and summaries by the International Institute for Sustainable Development, deep divides remained over whether the treaty should focus only on waste or cover the whole life cycle of plastics, including the production of new polymers and harmful chemicals, and over financing for developing countries. The committee agreed to resume at a date to be announced.
What does this mean for designers?
The debate in Geneva was partly a debate about design. A life-cycle approach would have pushed decisions on durability, repairability, recycled content and harmful additives upstream, to the stage where designers specify materials. Without a global instrument, those choices stay with designers, clients and whatever regional rules apply.
In the European Union, the Commission adopted the first work plan under its Ecodesign for Sustainable Products Regulation on 16 April 2025. It prioritises textiles, furniture, tyres, mattresses, iron and steel, and aluminium, and it points towards rules on durability, repairability and recycled content. Teams that already specify with these criteria will find new rules easier to meet.
Which sustainable materials can designers use today?
Reclaimed and reused materials
Reusing bricks, structural timber, steel sections, doors, fittings and furniture avoids new extraction and manufacture entirely. It often needs earlier planning and an audit of what a site already holds.
Bio-based materials
Timber from responsibly managed forests, bamboo, cork, hemp and straw store carbon while the plants grow and can be renewable when harvested at a sustainable rate. They need protection from moisture and fire, and sourcing evidence matters.
Recycled-content materials
Steel, aluminium and glass can be recycled many times, and recycled metal generally needs far less energy to produce than virgin metal. Where plastic is truly necessary, choose durable products designed for repair and recycling rather than single-use items.
Lower-carbon alternatives
Cement and concrete are major sources of emissions, so lower-clinker mixes and alternative binders deserve attention. Ask suppliers for the carbon figure and compare options on the same basis.
How should you choose between options?
Request an environmental product declaration for each major material, because it presents life-cycle data in a standard format that allows fair comparison. Check that claims name a scope and a number rather than a slogan, and compare alternatives for the same function. For a broader view of design choices, see our guide to sustainable product design and the overview of sustainable products.
Frequently asked questions
What are the most sustainable materials for buildings?
There is no single best material. Reclaimed components usually have the lowest impact, followed by responsibly sourced bio-based materials and recycled metals, but the right choice depends on structure, climate, durability and local supply. Compare options using life-cycle data for the same function.
Is recycled plastic a sustainable material?
It can be better than virgin plastic, because it reduces demand for new fossil-based material, but it is not automatically sustainable. Durability, additives, how easily it can be recycled again and microplastic release all matter, so choose long-lived products and avoid single-use items.
What happens next with the global plastics treaty?
The Geneva talks adjourned on 15 August 2025 without an agreed text, and the committee said it would resume at a date to be announced. Until a treaty exists, regional rules, procurement policies and design decisions continue to shape plastic use.