The use of nature-based materials in the construction industry

New trends such as circular construction and ecological construction have ensured that novel materials have found their way into the construction sector. The use of renewable raw materials and nature-based building materials forms an integral part of this. A status report, with some examples of materials and initiatives.

Trends in the construction sector

New-build homes must comply with strict regulations aimed at conserving energy and minimising environmental impact by using renewable ecology, rainwater collection and heat recovery ventilation.

New trends such as circular and ecological construction have ensured that new materials are finding their way into the building sector. The use of renewable raw materials and nature-based building materials forms an essential part of this.

The building materials that currently dominate the market are products such as cement and concrete, stone, steel, wood, glass and plastic (window frames, insulation), aluminium and composites. Most of these are made from finite raw materials, severely harm the environment and generate considerable waste.

The aim of circular construction is the (almost) endless reuse of these finite raw materials. Ecological construction has many aspects, but the use of natural materials (skeleton construction, clay construction, etc.) is central to this. The aim is also to be self-sufficient through the use of integral on-site water treatment, renewable energy, etc., in order to reduce the ecological footprint even further.

Applications for nature-based materials 

Structural requirements limit the extent to which steel and concrete can be replaced by wood. Materials made from natural products (flax, straw, wool, hemp, etc.) for non-structural parts or sheet material are already in use. Manufacturers such as Faay, LCDA and Unilin already make chipboard based on flax and hemp. Due to the stricter legislation on formaldehyde emissions, natural binders and glues (soya glue) are being used more often. Examples include Ekoboards, ECOBoards and Ecopanel.

People often opt for natural oils and alkyd systems with a high natural content for wood protection while products such as waterglass can be used to replace fossil-based products as impregnating agents. In veneer products, formaldehyde-based glues are already being replaced by nature-based products such as the Acrodur glue from BASF.

Lignin - a by-product of the wood and paper industry - is available in large quantities and is attractive because of its water-repellent and antimicrobial properties and high bonding strength. This makes it suitable for various applications, ranging from wood glue, a bitumen replacement in asphalt, chemical building blocks for polymers to a raw material for biofuels.

Another biopolymer that has been the subject of much research is PLA (polylactic acid), which can be made from sugars. This biopolymer can be processed into biocomposites in combination with lignin and cellulose fibres. PLA also finds use as an insulating material when it is foamed using CO2. It is available both as granules and as a sheet material and has the same insulation values as traditional expanded polystyrene (EPS).

Bio Foam, an alternative to EPS insulation based on PLA 
(Source: Termokomfort)

Holonite is another biocomposite (https://www.holonite.nl/). It is a composite stone material based on a binder that is 54 percent natural and which can be used for window sills, lintels and facade plinths.

Nature-based materials for interior finishing

Natural materials such as cork have long been used as floor coverings or wall finishings, but cast floors made from nature-based binders or composite floors that combine these binders with natural materials are also gaining in popularity. An example of this comes from Orineo (https://touchofnature.eu/), a Belgian company that combines the nature-based binder Oribond with by-products such as cranberry seeds or coffee grounds to make floors and furniture.

Parquet floors, carpets, floor coverings and subfloors are also being made from materials manufactured from natural raw materials. Textile fibres, adhesives and protection and maintenance products can also contain components from a natural source.

The stricter legislation on volatile natural compounds and formaldehyde emissions has led to the development of alternative glues, paints and coatings.

Inspirational initiatives

The Nature-based Offices project, led by Pro Natura, will develop four prototypes of nature-based materials in collaboration with its partners. This designer office furniture is based on natural fibres from landscape management by-products. In the course of 2020, Sirris will help in evaluating the materials used in this project, which is partly subsidised by Smart Hub Vlaams-Brabant.

A multifunctional building is made from circular economy construction materials on the 'Berg van Termunt' site in Tervuren. It will serve as a meeting room, youth centre and as a canteen for the local football team. Construction work is scheduled for 2021.

Wageningen University has prepared a catalogue of the building materials that will be on the market in 2019. This can be downloaded free of charge via the following link.

Vlaanderen Circulair and OVAM are putting out a call for projects to support innovative projects in circular construction. This will run until 23 September 2020.

The COOCK project, Biocoat, is an initiative from the Centexbel and Sirris research centres that aims to inform (Flemish) companies about the commercial potential of coatings and paints produced from natural building blocks.

(Source picture above: ID 125082919 © Tsung-lin Wu | Dreamstime.com)