When choosing materials for coatings and finishes in construction or renovation projects, it is essential to have a thorough understanding of the properties of each. Materials such as lime, gypsum plaster, synthetic paints and polymer coatings offer different solutions, each with its own characteristics.
Composition and origin
Lime: a natural tradition
Lime is an ancient material, used since Roman times. It is obtained by cooking and then hydrating limestone. Its two main variants, air lime and hydraulic lime, offer respectively a slow hardening in contact with carbon dioxide in the air or a faster hardening with water. As a natural material, free of chemical additives, lime offers a purity that is difficult to match.
Gypsum plaster: practical but fragile
Gypsum plaster, derived from chalky rocks, is also a natural material, widely used for its workability and quick hardening qualities. However, it is less suitable for use in environments subject to moisture, which limits its applications in such areas as bathrooms or kitchens.
Synthetic paints: customisable but of chemical origin
Synthetic paints are made from polymers and chemical solvents. They are popular for their wide range of colours and finishes, but are derived from industrial processes that make them less environmentally friendly than lime or gypsum plaster. While they offer broad custom possibilities, they contain VOCs (volatile organic compounds), which can compromise indoor air quality.
Polymer coatings: high resistance, low breathability
Polymer coatings are used primarily in industrial or high-intensity use settings for their mechanical and chemical resistance. Despite their durability, they are synthetic resin-based chemicals and are typically waterproof, which limits breathability and can lead to condensation problems.
Technical features
Durability and maintenance
Lime: a material that improves over time
One of the main advantages of lime is its long-term durability. The carbonation process, which continues even after application, allows it to progressively harden and therefore to become increasingly resistant over the years. Lime is also self-repairing: small cracks close up on their own thanks to its ability to react with carbon dioxide, which reduces the overall need for maintenance.
Furthermore, lime is particularly suitable for restorations, since it is compatible with ancient building materials and does not generate mechanical stresses that can damage historical structures. This characteristic makes it preferable in contexts where conservation is a priority.
Gypsum plaster: sensitive to humidity
Although it offers a smooth and easy-to-work surface, gypsum plaster is more delicate in terms of resistance over time, especially in humid environments. It can deteriorate easily when in contact with water, requiring more frequent maintenance. This makes it less suitable than lime in environments such as bathrooms, kitchens or spaces exposed to significant climate variations.
Synthetic paints: easy to apply but less long-lasting
Synthetic paints offer immediate resistance, but in the long term they can show signs of wear such as cracking or fading, especially when exposed to difficult environmental conditions (UV rays, humidity, chemical agents). Their maintenance is relatively simple, but periodic repainting is necessary, especially in outdoor spaces, to maintain the original appearance.
Polymer coatings: long-lasting, but expensive
Polymer coatings offer long-lasting durability and mechanical resistance, but require professional maintenance to preserve their quality intact over time. They are suitable for environments that require high resistance to wear, but in residential environments or interior spaces, lime offers greater versatility without sacrificing longevity.
Breathability and Wellbeing
Lime: natural regulation of the microclimate
One of lime’s most distinctive and appreciated qualities is its high breathability. It allows the passage of humidity through the walls, helping to maintain a balanced microclimate inside buildings. This ability to absorb and release humidity reduces the risk of condensation and mould, improving the general healthiness of interior spaces. In humid or poorly ventilated environments, lime is undoubtedly the most recommended choice to ensure healthy indoor air free of pathogens.
Gypsum plaster: breathable, but limited
Gypsum plaster also offers a certain degree of breathability, but not to the level of lime. It can absorb moisture, but in particularly humid environments such as kitchens or bathrooms, it can show signs of deterioration and encourage the formation of mould, especially if not treated correctly.
Synthetic paints: potential obstacles to breathability
Synthetic paints vary in terms of breathability. While some modern versions are designed to be breathable, many do not allow adequate moisture exchange, trapping moisture in the walls. This can lead to condensation problems, especially when these paints are applied over historically breathable surfaces, such as lime or gypsum plaster.
Polymer coatings: waterproof, but not breathable
Polymer coatings, designed to be waterproof, do not allow for breathability. While they are great for protecting outdoor surfaces or industrial spaces from water infiltration, in residential settings or in historic buildings, this lack of breathability can cause structural and environmental problems over time.
Environmental Sustainability
Lime: a sustainable choice
One of the most important aspects of lime is its low environmental impact. Lime production requires less energy consumption than industrial materials such as synthetic paints and polymer coatings. Furthermore, during the carbonation process, lime reabsorbs part of the CO2 emitted during its production, reducing its overall impact on the environment. As a natural material, free of harmful chemical compounds, lime contributes to creating healthier and more sustainable environments.
Gypsum plaster: natural but limited
Gypsum plaster is a natural and recyclable material, but its ability to resist over time is limited, and this can lead to more frequent replacements than lime, increasing the consumption of materials in the long term.
Synthetic paints: a greater environmental impact
Synthetic paints are derived from chemicals, which makes their environmental impact greater, especially in terms of the production and emission of VOCs during application. Although some modern formulations are more environmentally friendly, they are still industrial materials that will never match the sustainability of lime.
Polymer coatings: long-lasting, but not very eco-friendly
Polymer coatings, although long-lasting, are difficult to recycle and derive from non-renewable resources. Their production process has a high energy impact and is usually less respectful of the environment than natural materials such as lime.
In this comparison guide, lime clearly stands out as a versatile, natural and high-performance material. Compared to conventional materials such as gypsum plaster, synthetic paints and polymer coatings, lime offers a unique combination of breathability, durability and environmental sustainability, which makes it the preferred choice in projects aimed at promoting healthiness, longevity and respect for the environment.
Particularly in restoration projects, residential spaces and humid environments, lime proves superior to other materials, ensuring living comfort and low environmental impact. Although synthetic and industrial materials may be more suitable in specific contexts such as industrial environments or high-wear areas, for those looking for a natural and top-quality solution, lime remains a preferable choice.