Why natural paints?
Synthetic paints, which are massively used both in house painting and in decorative painting (alkyd, vinyl, acrylic, latex paints, etc.) are composed of ingredients from petrochemicals and heavy chemicals.
Though, in the course of the 20th century, they have replaced, natural paints (which have been used since Antiquity), we are now aware of the harmful effects of synthetic paints.
The binders of these paints and the solvents they contain have indeed a deleterious impact on health, the environment and buildings.
That is why it is important to prioritize natural paints, which are non-toxic, ecological and more suitable for buildings, especially ancient ones.
The range of natural paints, mineral or organic based, is wide. Among other sources, natural paint can be composed of : lime, casein (milk protein), egg, silicate (potassium), vegetable oils, arabic gum, clay, skin glues, natural resins and waxes, algae, even beer.
They should be selected according to their properties and the project, so as to be adapted to the medium and the context.
These paints can be elaborated on site, and based on natural and local products, or they can be selected from manufacturers who now offer more and more products that do not contain any hazardous materials, or that are not harmful to people, the environment and buildings alike.
HEALTH IMPACT
Synthetic paints contain toxic products which are released during and after their application. To prevent the development of mold and bacteria, or to improve some characteristics of the product, a plethora of components are often added to these paints, such as :
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chemical additives
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pigments containing VOCs (Volatile Organic Compounds)
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biocides
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and even heavy metals
These materials, which permeate the fabrics and remain present in the air for several months, are toxic. They have an impact on the health of the artists-craftsmen who apply them, as well as on the health of the inhabitants and users of the places.
Natural paints, which are made from biodegradable and renewable materials (binders and pigments), to which no additives or preservatives are added, are non-toxic. Most of the time, they have a greater diffusion capacity than that of synthetic paints. This therefore contributes to creating a healthy interior.
ENVIRONMENTAL IMPACT
Synthetic paints contain polluting ingredients and consume a large amount of energy throughout their life cycle.
The ingredients contained in these paints, which come from the petrochemical industry, are toxic and non-biodegradable ; and are discharged into the waste water drainage system during their production, use and recycling. Furthermore, the fine particles they release are not treated by any wastewater treatment plant. What has the effect of polluting :
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streams
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oceans
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soils
In addition, production of synthetic paints requires a lot of embodied energy, i.e. the sum of the energies spent and consumed for :
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creating and packaging the product
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transporting it to distribution sites
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storing, distributing and selling it
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using, maintaining and recycling it
Even when recycled, synthetic paints leave behind a number of polluting residues. This has an impact on the environment, and contributes to the deterioration of marine fauna and flora in particular.
Natural paints contain largely biobased, biodegradable and renewable ingredients.
On one hand, the materials used, which are non-toxic, can most of the time be rejected in household waste, and at times even be composted.
On the other hand, the impact of these paints on the environment is reduced throughout their life cycle, from the extraction of raw materials to their treatment downstream. When they are made on site with local materials, the energy used is therefore reduced since this does not involve packaging, transport or storage. When ordered from manufacturers, they can be sold in powder form, which reduces the embodied energy used and avoids the unnecessary transport of water which is directly added by the end user.
IMPACT ON THE BUILDING
Synthetic paints do not generally have a very long lifespan, which means one is forced to renew them regularly. Although they are presented as multi-support, they are not suitable for all materials, especially in ancient buildings (wood, stone, brick, etc.).
These paints form a plastic film which waterproofs the support and does not let it breathe, which :
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prevents the natural regulation of humidity in the ambient air
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causes mold growth
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favors infiltration and capillary rise which damage the structure
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promotes electrostatic charges, thus attracting dust and dust mites
These effects, while they may appear as minor material damage, nevertheless contribute to damaging the building (detachment of decorations, crumbling of woodwork, appearance of green or black spots, etc.), and may, in the most serious cases, endanger the structure of the building.
Most natural paints are extremely durable over time. This can be illustrated by the exceptionally well conserved painted decorations dating back several centuries.
Natural paints have a large range of different properties (breathability, plasticity, coverage, compatibility with certain pigments, texture, hardness, drying time, etc.) depending on the binders used in their composition. This explains why each one is more or less adapted to the different supports hosting the decorations.
They are, for some, breathable and thus prevent the development of infiltration and capillary rise in the ceilings and walls, thus preserving the structural and bacterial balance of the building.
As natural paints are antistatic, they eliminate static charges, which reduces dust and dust mites.
Some of them, such as lime, have natural properties that avoid the use of preservatives or chemical additives (antifungal type) because their PH prevents the formation of mould.