Introduction: Why Impregnation Matters
Brickwork, natural stone, concrete, and other mineral building materials are naturally porous. These pores are essential because buildings need to allow moisture transport and remain vapor permeable. At the same time, penetrating water is one of the main causes of building damage. Examples include frost damage, pollution, algae and moss growth, salt efflorescence, and deterioration of facade materials.
A high-quality impregnation product does not create a sealing film on the surface. Instead, it makes the substrate water-repellent while maintaining vapor permeability, allowing moisture vapor to escape from the building structure.
Modern facade impregnating agents based on silane and siloxane technology are among the most widely used solutions for protecting mineral building materials. Research has shown that silane/siloxane water repellents can penetrate deeply into mineral substrates while maintaining the original vapor diffusion properties of the material.
The development of impregnation technology, however, has changed significantly over the decades. While solvent-based products were traditionally the standard choice for professional applications, the market is increasingly moving towards modern water-based systems.
The Historical Development of Solvent-Based Products
The First Generations of Building Protection
Protecting construction materials against moisture is not a modern invention. For centuries, natural materials such as oils, waxes, and resins were used to reduce the sensitivity of wood, stone, and other materials to water.
With the development of the petrochemical industry during the 20th century, synthetic solvents became widely available. These solvents made it possible to dissolve active substances more effectively and transport them deeper into porous building materials.
A major breakthrough in facade protection came with the introduction of silicone-based technologies. Silanes and siloxanes proved particularly suitable because they:
- provide excellent water repellency;
- penetrate deeply into mineral substrates;
- do not completely block the pores;
- preserve the natural appearance of brick and stone.
Solvents played an important role in these systems because they acted as carriers, allowing the active ingredients to penetrate deeply into the substrate.
Why Were Solvent-Based Impregnation Products So Popular?
For many years, solvent-based impregnation products offered several technical advantages.
1. Excellent Penetration
Due to their low viscosity, solvent-based formulations could penetrate deeply into the capillaries of brick, concrete, and natural stone.
This was particularly important for dense mineral materials where deep penetration was required to achieve long-term water repellency.
2. Suitable for Difficult Substrates
Solvent-based systems generally offered excellent wetting properties, making them suitable for substrates that were more difficult to impregnate.
Examples include:
- dense clinker bricks;
- natural stone;
- older mineral surfaces;
- heavily weathered facades.
3. Fast Drying
The solvent carrier evaporated relatively quickly after application, allowing the hydrophobic effect to develop within a short period.
4. Proven Long-Term Performance
Products such as Remmers Funcosil SNL, Funcosil BI, Funcosil AS, and Funcosil SNL Reukneutral were used for many years in professional facade renovation projects because of their reliable performance and proven durability.
Funcosil SNL, for example, was a colorless hydrophobic impregnation product based on silane/siloxane technology with an organic solvent carrier.
The Disadvantages: VOC Emissions and Environmental Considerations
Although solvent-based impregnation systems were technically very successful, increasing attention was given to the environmental and health aspects of volatile organic compounds (VOC).
VOC stands for Volatile Organic Compounds. These substances evaporate during and after application.
Important considerations include:
- emissions into the air;
- odor during application;
- impact on working conditions;
- stricter environmental regulations;
- increased demand for sustainable construction products.
As environmental requirements became stricter, the construction chemical industry started developing alternatives where water replaced organic solvents as the main carrier.
The Technical Development: From Solvent-Based to Water-Based Impregnation Systems
The transition from solvent-based to water-based impregnation products was not a simple replacement process. From a chemical perspective, it required significant technological development.
Water has fundamentally different properties compared with organic solvents:
- water does not naturally mix with silicone-based active ingredients;
- penetration behaviour can be different;
- maintaining a stable formulation requires advanced chemistry;
- drying and curing processes follow different mechanisms.
Through advances in emulsion technology, dispersion chemistry, and formulation science, manufacturers succeeded in creating stable water-based systems in which silanes and siloxanes could be effectively dispersed.
This development resulted in a new generation of facade impregnation products combining:
- high active ingredient concentrations;
- effective penetration into mineral substrates;
- long-lasting hydrophobic protection;
- low odor during application;
- reduced environmental impact.
Modern water-based impregnation products are therefore not simply an environmentally preferred alternative; they represent a significant technological evolution in construction chemistry.
Silane and Siloxane: The Foundation of Modern Facade Protection
Most high-quality facade impregnation products today are based on silane, siloxane, or combinations of both technologies.
These substances belong to the silicone chemistry family and are specifically designed for protecting porous mineral building materials.
Silane Technology
Silane molecules are relatively small and can penetrate deeply into the capillary structure of mineral materials.
This deep penetration allows the active ingredients to react inside the substrate rather than forming only a surface coating.
Siloxane Technology
Siloxanes consist of larger molecular structures and contribute to the long-lasting hydrophobic effect.
They provide durable water repellency and improve resistance against weather influences.
The Combination of Silane and Siloxane
The combination of silane and siloxane provides an optimum balance between:
- deep penetration;
- chemical bonding within the substrate;
- long-term water repellency;
- preservation of vapor permeability.
One of the most important advantages of this technology is that the facade remains breathable. Water vapor can still escape from the building structure, while liquid water from rain is prevented from penetrating.
This makes silane/siloxane impregnation systems particularly suitable for:
- brick facades;
- natural stone;
- concrete structures;
- mineral renders;
- historical buildings.
Does Water-Based Automatically Mean Lower Quality?
A common question is whether water-based impregnation products perform less effectively than traditional solvent-based systems.
The answer is: not necessarily.
The first generations of water-based products sometimes had limitations compared with solvent-based alternatives. Early formulations could have reduced penetration or required more careful application.
However, modern emulsion technology has significantly improved performance.
Today, the effectiveness of an impregnation product is mainly determined by:
- the type of active ingredient;
- the concentration of active substances;
- the quality of the formulation;
- compatibility with the substrate;
- correct application method.
A professional water-based silane/siloxane impregnation system can achieve the same protection objectives as traditional solvent-based products.
The choice between systems should therefore not be based solely on whether a product contains water or solvent, but on the overall formulation quality and suitability for the intended application.
The Development Within Remmers: Moving Away from Traditional Solvent-Based Impregnation Products
Manufacturers of professional construction chemicals have followed the same technological trend.
Remmers has been one of the leading suppliers of facade protection systems for many decades. Its Funcosil range has become well known among professionals involved in facade renovation, monument conservation, and building protection.
For many years, Remmers supplied various solvent-based impregnation products, including:
- Funcosil SNL;
- Funcosil BI;
- Funcosil AS;
- Funcosil SNL Reukneutral;
- Funcosil SL.
These products were valued for their:
- excellent penetration properties;
- reliable hydrophobic effect;
- proven durability;
- suitability for demanding mineral substrates.
Funcosil SNL, in particular, became one of the most recognized facade impregnation products in Europe.
Its success was based on a combination of silane/siloxane chemistry and solvent-based carrier technology, which allowed the active ingredients to penetrate deeply into porous mineral materials.
Why Is Remmers Changing Its Product Range?
The move towards water-based systems is driven by several developments:
1. Environmental Regulations
European legislation has increasingly focused on reducing emissions of volatile organic compounds (VOC).
Construction products are increasingly expected to contribute to healthier working environments and lower environmental impact.
2. User Requirements
Professional applicators and contractors increasingly demand products that are:
- low odor;
- safer to handle;
- easier to use in occupied buildings;
- more environmentally responsible.
3. Advances in Chemical Technology
Modern water-based formulations can now provide performance levels that were previously only achievable with solvent-based products.
This allows manufacturers to combine technical performance with improved sustainability.
Funcosil SNW: The Next Generation of Facade Impregnation
As part of this development, Remmers introduced products such as Funcosil SNW.
Funcosil SNW is a water-based hydrophobic impregnation product based on silane/siloxane technology in emulsion form.
It has been developed as a modern alternative to several traditional solvent-based Funcosil systems.
Key characteristics include:
- water-based formulation;
- solvent-free technology;
- low odor;
- vapor permeability;
- suitable for mineral substrates;
- durable water-repellent protection.
The product is designed for professional facade protection while meeting modern environmental and application requirements.
Funcosil SNW Compared with Funcosil SNL: A New Generation of Facade Protection
The transition from Funcosil SNL to Funcosil SNW represents a broader development within the construction chemical industry.
It is important to understand that this change does not mean that the traditional solvent-based products were technically inferior. On the contrary, products such as Funcosil SNL achieved an excellent reputation because they delivered reliable and durable protection for many years.
The reason for the transition is primarily related to changing requirements regarding:
- environmental impact;
- VOC emissions;
- workplace safety;
- odor reduction;
- sustainable construction practices.
The fundamental protection mechanism remains the same: creating a durable hydrophobic effect inside the mineral substrate through silane/siloxane chemistry.
The difference lies mainly in the carrier system:
| Traditional system | Modern system |
|---|---|
| Organic solvent as carrier | Water as carrier |
| Stronger odor during application | Low odor |
| Higher VOC emissions | Reduced emissions |
| Excellent penetration | Optimized modern penetration technology |
| Long history of proven performance | Latest generation sustainable technology |
For building owners, contractors, and applicators, this means that modern water-based systems can provide the same objective: protecting facades against water penetration while maintaining the natural breathability of the construction material.
The Future of Facade Impregnation
The direction of development within construction chemistry is clear:
fewer solvents, more sustainable water-based technologies.
This development is part of a wider movement towards more environmentally responsible construction and renovation.
Important trends include:
Lower Emissions
Reducing VOC emissions contributes to improved air quality and safer working conditions.
Sustainable Renovation
Protecting existing buildings extends their service life and reduces the need for replacement materials.
A well-maintained facade requires fewer repairs, resulting in lower material consumption and reduced environmental impact.
Safer Application
Low-odor and water-based products are particularly valuable when working:
- in residential areas;
- near occupied buildings;
- in historic buildings;
- in public spaces.
Improved Product Performance
Modern formulations continue to improve through advances in:
- polymer chemistry;
- nanotechnology;
- emulsion technology;
- active ingredient optimization.
The future of facade protection will therefore likely combine:
- high durability;
- low environmental impact;
- ease of application;
- improved user safety.
Frequently Asked Questions About Water-Based and Solvent-Based Impregnation Products
Is a water-based impregnation product better than a solvent-based product?
The answer depends on the application and formulation quality.
Modern water-based silane/siloxane impregnation products can provide excellent long-term protection and offer additional advantages such as lower odor and reduced VOC emissions.
For many applications, water-based products are now the preferred solution.
Can Funcosil SNL be replaced by Funcosil SNW?
Yes, in many applications Funcosil SNW has been developed as a modern alternative to traditional Funcosil products such as Funcosil SNL.
However, the suitability depends on:
- the type of substrate;
- the condition of the facade;
- the required penetration depth;
- application conditions.
A professional assessment remains important for complex projects.
Does facade impregnation close the pores of brick or stone?
No.
A high-quality silane/siloxane impregnation does not create a closed coating layer.
Instead, it modifies the internal surface of the pores, making them water-repellent while allowing water vapor to pass through.
This is why professional impregnation systems are called hydrophobic treatments rather than sealing coatings.
How long does facade impregnation remain effective?
The durability depends on:
- the product quality;
- the amount of active ingredient applied;
- the substrate;
- weather exposure;
- correct preparation and application.
Professional silane/siloxane systems can provide protection for many years when correctly applied.
Conclusion: The Evolution from Solvent-Based to Water-Based Protection
Solvent-based impregnation products have played an important role in professional facade protection for decades.
Products such as Remmers Funcosil SNL, Funcosil BI, Funcosil AS, and Funcosil SNL Reukneutral became trusted solutions because of their excellent penetration characteristics and proven durability.
However, construction chemistry continues to evolve.
Modern water-based impregnation products combine:
- advanced silane/siloxane technology;
- reduced environmental impact;
- lower odor;
- improved user comfort;
- professional long-term protection.
The transition from traditional solvent-based products towards modern water-based systems such as Funcosil SNW should therefore not be seen as a reduction in quality.
It represents the next step in the development of sustainable, high-performance facade protection.
For professionals and building owners, the goal remains unchanged:
to protect mineral building materials against moisture while preserving their natural appearance, durability, and breathability.
Sources and Technical References
- National Association of Home Builders (NAHB) – Silane and Siloxane Water Repellents for Concrete and Masonry
Research overview on the performance, penetration, and vapor permeability characteristics of silane/siloxane water repellents. - Remmers Technical Product Information – Funcosil SNL
Technical documentation regarding solvent-based silane/siloxane facade impregnation. - Remmers Technical Product Information – Funcosil SNW
Technical documentation regarding modern water-based silane/siloxane facade impregnation technology. - European VOC regulations and construction product sustainability developments
Background information on the reduction of volatile organic compound emissions in construction materials.
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