Materials
In the following list, we break down each material we use during the making process of our shoes. By doing so we inform our clients and stakeholders about the environmental implications of different materials, empowering them to make informed decisions and to inspire transparency. By sharing our material list, we show our commitment and dedication to responsible and ethical practices. By publicly disclosing our materials we can be held accountable for our choices. This provides a basis for continuous improvement.
100% Used sneakers
Our most important raw material is vintage footwear. Usually, our clients send in their own sneakers for us to Resoul ™. For our other styles we collect sneakers from all over Europe. We source sneakers through our recycling partner Vive in Poland. Next to this we also use well known re-sell platforms such as Ebay, Vinted and Marktplaats to source specific styles. We also regularly receive donations from brands and clients.
Flip side:
We do not have a solution yet for the used soles we remove from old shoes.
What: Find a suitable way to reuse or recycle the soles.
When: 2026
Our vegetable tanned leather
All the virgin leather we use to make our shoes is 100% vegetable tanned. The tanning process is what transforms a skin or a hide into leather. There are different techniques to produce leather. Chrome tanning, the most common method of tanning, uses chemicals. Opposed to Vegetable tanned leather, which is a technique that makes use of natural tannins derived from plant materials such as tree bark, leaves and fruits. This traditional method has been used for centuries. We currently work with an Italian tannery, from the region of Tuscany that produces our leather, called Volpi. By working with them we invest in preserving traditional craftsmanship because they are a member of Consorzio Vera Pelle. By being a member of this consortium, they undergo a periodic audit and comply with their sustainability manifesto. Vegetable tanned leather is extremely durable, it wears down slowly and while it does it becomes more beautiful after each use. Due to care, use and sunlight, vegetable tanned leather develops a patina; a beautiful dark sheen that only develops on vegetable tanned leather because of how it is tanned.
Flip side:
Leather is a byproduct of the meat industry. Although the definition of byproduct can be discussed, we are convinced it is an economic byproduct, because more than 97% of the economic value of a cow comes from its meat. However, if the cow skins would go into landfill instead of being made into leather, they would emit 94 kg co2/square meter. Opposed to 110 kg co2/square meter when the skins are turned into leather. Leather in general has a large carbon footprint in comparison to other materials. At the moment we choose to use vegetable tanned leather because of its durability, repairability and beauty. We are convinced that the combination of these three lets us create beautiful products that will be loved, kept, repaired and worn. Using the products you have is a sustainable act. Compared to alternatives, which are usually synthetic, leather biodegrades much faster. The most common alternative is synthetic leather, which is essentially plastic that is made from fossil fuels. Depending on its tanning method, leather can biodegrade in 50 years. While synthetic leather takes up to 200 years to biodegrade.
What: Research Leather Resoul™ alternatives
When: 2026
Our cork
Cork is an amazing product in terms of comfort, durability, design and ecological footprint. We source our big, granulated cork sheets from a family business based in Portugal, called 3D Cork. This component comes from a tree named cork-oak and is 100% natural. In production the cork granules are mixed with rubber to create the sheets. It is then hand shaped into wedges and used for our shoes. We have tried to use 100% pure cork; however we had issues where the sole would break and crack, therefore we choose to switch to a cork and rubber blend.
Our rubber
The rubber soles we use for our shoes are produced by Vibram made of high-quality EVA, which is a by-product of oil. Even though it offers great comfort and durability to the wearer, this material is virgin, hardly recyclable and has a terrible carbon footprint. Throughout the industry, finding a good alternative to this material is a great challenge. Through the European Union we have been supported through the Worth Partnership to develop more sustainable soles, that is why we are currently also using TPU outsoles, produced by Givans Fondi. Which is a fully recyclable material.
Our glue
Shoemaking implies the use of glue in many steps, and we have found a way to tackle it, by stitching instead of gluing. However, we cannot replace all of the steps with stitching. Little by little, doing wearing tests, we were able to replace the solvent based glues for Renia Aquilim 315, a water-based alternative. So far, 20% of the glue we use in our studio is water-based.
What: Research if it is possible to use Renia Aquilim 315 for all glueing steps.
When: Research to be completed in 2025
Shipping
When a client orders a pair of our shoes we ship through DHL GoGreen, they offset at least 30% of the CO2e.
Flip side:
Local production would be preferred above shipping our shoes over the world. Currently, we have no plans to set up local production sites in other places than Amsterdam, but we will be looking into offsetting more CO2e.
What: Offset more than 30% CO2e
When: 2025
Packaging
We use minimalist packaging. Where possible we use recyclable or recycled materials, we aim for functional and environmentally responsible packaging. Our shoe boxes are made from recycled cardboard, and wrapped in newspaper before shipping. By doing so, we are able to use one box per client instead of double boxing an order.
Flip side:
At the moment we are using our last supply of plastic tape, when it is finished we will switch to a more sustainable option.