Low Carbon Materials

Biodegradable or recyclable, low-carbon materials are materials with a low carbon footprint* and low environmental impact. They are generally derived from natural resources (organic or mineral). We distinguish between biobased materials, which are derived from biomass such as wood, hemp, straw, sheep’s wool, etc., and geobased materials, which are derived from minerals such as raw earth. Some materials can also come from recycled materials (textile fibres, paper … etc.) as part of the circular economy and the revalorization of waste products
The interest of biobased materials in renovation is demonstrated, by heigh performance, their compatibility with old materials as well as their response to the objectives of reducing the carbon footprint of the building stock and the environmental regulation RE2020. Thus, with our commitment to the ecological transition and in support of the circular economy, we, at RETHINK, regularly explore and develop a material library counting today nearly 100 materials which we try to implement in our projects as often as possible.

*The carbon footprint corresponds to the carbon equivalent of the greenhouse gas emissions generated over the entire life cycle of a material, from the extraction and transformation of the raw material to the transportation and recycling process or its degradation at the end of life.

Raw earth brick © Rethink

Raw Earth Brick « Adobe »

Use:

Structural wall or infill.

Features:

Earth is a 100% natural material. It could be sourced directly from the construction site helping reduce the emission of greenhouse gases generated from material transportation. The mud brick is molded, compacted then dried before laying. Its carbon footprint is lower than that of the terracotta brick given that its manufacture does not require energy intensive baking.
The on-site application is facilitated (compared to rammed-earth building for example) thanks to the prefabrication in workshops and the reduced size of the elements. Mud bricks insure an excellent thermal and hygrometric properties: heat storage, regulation of ambient humidity.

Compressed earth block – ARGILUS © Rethink

Compressed Earth Brick

Use:

Structural wall or infill.

Features:

Compressed earth brick is an environmentally friendly and sustainable material made from pure clay. It is dense and resistant to compression and can be used as a load-bearing or infill wall. Its stabilization with lime prevents moisture build-up and swelling. Also, in addition to acoustical insulation, CEB has excellent thermal features: thanks to its inertia, it can store heat and release it later while helping regulate ambient humidity at the same time.

Terracota Tiles – RAIRIES MONTRIEUX © Rethink

Terracota Tiles

Use:

Cladding.

Features:

The terracotta tile is an entirely mineral material made with clay and sand. The raw materials come from quarries. The combustion of the mineral mix ensures resistance to weathering and mold. The lifespan of the tile can exceed 100 years which makes it a material that can be reused at the end of its life on other buildings if the fixing system initially used allows its deconstruction without degradation.

Bamboo boards -MOSO © Rethink

Bamboo

Use:

Interior and exterior flooring, cladding, plywood board.

Features:

Resulting from a recomposition of natural bamboo, bamboo boards keep the natural features of the original material. Bamboo is very resistant to humidity: it contracts and swells less than most of solid wood species, which gives a stability to the building.
Bamboo is also an abundant resource and grows very fast: up to one meter per day. Each year, poles between 4 and 5 years old are harvested, which allows younger bamboos to mature. During growth, it absorbs a bigger amount of CO2 than that generated during the production process. For these reasons it is considered to be a sustainable material.

Burnt wood – NOIRDEBOIS © Rethink

Burnt Wood

Use:

Cladding.

Features:

Burnt wood results from a wood protection technique that consists of deeply burning of a wood board to obtain a thick carbon layer on the surface giving an infinite variation in appearance and texture.
In addition to offering natural UV protection and moisture resistance, this technique prevents the growth of insects and fungi and significantly delays the spread of fire.

Cork – WEBER © Rethink

Cork Board

Use:

Thermal and acoustical insulation.

Features:

Cork is a natural material. Its fabrication in form of boards does not require any polymer. Boards can be obtained by recycling of cork plugs. Expanded cork is an excellent thermal and acoustic insulation with a good resistance to water and humidity. Like every bio-based insulation materials, it is a breathing material that is suitable for ancient building renovation. For all these qualities, its price is quite high compared to other materials on the market.

Composite wood – LAMEO © Rethink

Composite Wood with Integrated Aluminium

Use:

Cladding ( Potentially structural)

Features:

Composite wood is made from wood flour mixed with plastic resin. This hybrid system minimizes the carbon footprint. The production of the material complies with high ecological standards. The wood used is made from recycled pine, which is good for the environment. Even after decades in the sun, the decking boards can easily be reused.
Naturally resistant to water, insects, rot and frost. The planks do not require any additional treatment, such as brushing, painting or impregnation. This makes it sometimes more durable than natural wood construction.

Wood wool – STEICO © Rethink

Wood Wool

Use:

Thermal and acoustical insulation

Features:

Wood wool panel can be flexible, rigid or semi rigid. Its manufacture allows the valuation of of sawdust from sawmill waste. Wood wool is a high-performance thermal and acoustical insulator that offers good protection against summer heat.
These insulating panels have an advantageous carbon footprint, even though their manufacture requires binders and additives. Several manufacturers are now substituting these pollutants with natural and biodegradable products (e.g., starch, etc.)

Acoustical wood panel – LIGNO ACOUSTIC © Rethink

Acoustical Wood Panel

Use:

Acoustical covering : walls and ceilings

Features:

This wood acoustical panel is a composite material made of three laminated plies with spruce laths on the outside and wood fibers for sound absorption on the inside. This material combines sound absorption with a wood finish for sound comfort and aesthetic quality of interior spaces.

Acoustical false ceiling- KNAUF © Rethink

Acoustical False Ceiling

Use:

Ceiling, acoustical insulation.

Features:

This bio based false ceiling is made from spruce wood wool. It is stabilized during a mineralization process using a binder made of cement and lime. It is an excellent acoustical insulation material thanks to its technical properties. The panel does not require any extra finishes for the natural visual aspects given by the fibers.

Hempcrete – ISOHEMP © Rethink

Lightweight Hemp Concrete

Use:

Insulation, infill.

Features:

The lightweight hemp concrete is a composite material made of hemp chips and Prokalk lime (mix of air and hydraulic lime). It is used internal and external insulation of existing buildings .
Hempcrete is also used as infill for wood framed structures in new construction. Its composition gives it excellent thermal,acoustical and hygrometric insulation features.

Rubber flooring – NORA © Rethink

Natural Rubber

Use:

Floor covering.

Features:

A material made entirely from natural and industrialized rubber often mixed with natural minerals, color pigments and other components. The mixture is then cut and flattened under very high heat and pressure. The final product is a uniform, water-resistant and durable product.

Linoleum- GERFLOR © Rethink

Linoleum

Use:

Floor and wall covering

Features:

Commonly used to designate a floor covering made of plastic materials, the term « lino » is generally synonymous with « chemical » in the common sense. However, linoleum is an environmentally friendly flooring due to its composition. Indeed, made with from chalk, resin, natural pigments, jute, wood powder, cork bark and linseed oil, linoleum proves to be a natural and environmentally friendly product, compared to other polymers like PVC.

Cellulose wadding – OUATECO © Rethink

Cellulose Wadding

Use:

Thermal and acoustical insulation

Features:

Cellulose wadding is made from primary bio-based raw material produced from recycled papers and cardboards. It is an excellent insulation material and has a lifespan of up to 20 years. Papers and cardboards are crushed, their fibres removed and then mixed with boron salt. Textile fibres are sometimes added to the mix.
Most of the time cellulose wadding is sold as bulk fibres for blow molding, or spraying, or sometimes as panels. Cellulose wadding has the advantage of being affordable compared to other natural insulation materials on the market. However, it is not resistant to water and cannot be put outside or in wet areas.

Polyurethan Foam – RECTICEL INSULATION © Rethink

Recycled Polyurethane Foam

Use:

Acoustical insulation.

Features:

With its polymer composition, polyurethane is produced from petrochemical products. It is harmful for the environment and non biodegradable. However, polyurethane has excellent thermal performances when used as thin insulation material, which makes it a common material in the building sector. Its recycling as an acoustic insulation foam aims to reduce the impact on environmental contamination.

Textile tile – PIERRE PLUME © Rethink

Recycled Textile Tiles

Use:

Acoustical insulation, interior wall covering.

Features:

Textile tiles are made from textile fibers originating from industrial waste and recycled clothes. They often come with a heterogeneous aspect as the fibers are mixed randomly. In addition to their acoustical insulation properties, textile tiles are light weight and add an aesthetic touch to various types of spaces. However, they have low water and impact resistance properties and their maintenance is difficult.
Being “upcycled”and therefore expensive, textile tiles are intended for high-end interior spaces that have particular acoustical and aesthetic needs (offices, meeting rooms, hotels, restaurants, reception halls, private homes, etc.).

Draining flooring- PROURBA © Rethink

Draining floor

Use:

External floor coverings.

Features:

Used in the development of outdoor spaces (car parks, roads, cycle paths, etc.), draining floor coverings are made of mineral aggregates(often marble or quartz, preferred for their hardness) bound by a resin. The interstices created between the aggregates during the pouring process allow water to pass through in rainy weather, or to keep air circulating, thus guaranteeing the thermal regulation of the surface.
By varying the tone of the aggregates or the color of the resin, this flooring offers a variety of finishes and adds an aesthetic touch to outdoor spaces.

Solar panel – DUAL SUN © Rethink

Solar Panel

Use:

Energy

Features:

The solar panel is a system that is able to capture solar energy and transform it into an electrical continuous current. The solar energy is part of sustainable energies.

Manufacturer :

DUALSUN

Author: Christian Horn is the head of the architecture and urban planning office RETHINK in Paris, France