What is silicate paint and how do I choose it?

Silicate paint is becoming increasingly popular for its many qualities, particularly when it comes to renovating old buildings or facades. However, it remains less well known than other types of paint. If you’d like to find out more about this type of coating and how to choose the right one for your projects, this article will guide you step by step.

What is silicate paint?

Silicate paint is a mineral paint that differs from conventional synthetic resin- or oil-based paints. Its main composition is based on potassium silicate, a natural binder that gives it its unique properties. It is fixed by a chemical reaction with the substrate, called “silicification“, which creates a very strong, long-lasting adhesion.

Unlike resin-based paints, which create a film on the surface of the substrate, silicate paint penetrates the material, allowing walls to breathe more easily while providing effective protection against the elements.

What are the advantages of silicate paint?

Silicate paint offers a number of advantages:

1. Excellent durability: Thanks to the chemical reaction of silicification, silicate paint is extremely long-lasting. It is highly resistant to weathering and UV rays, making it an ideal choice for façades exposed to the elements.
2. Resistant to mould and fungi: Thanks to its mineral nature and high pH, it does not encourage the growth of mould and algae. This makes it an environmentally-friendly solution for buildings in damp environments.
3. Breathability: Unlike synthetic paints, silicate paint allows walls to “breathe”. This means that interior moisture can escape, reducing the risk of condensation and structural damage.
4. Compatibility with traditional materials: This paint is particularly suitable for old or historic buildings, as it does not alter the structure of the walls and can be used on materials such as stone, brick or concrete.

When should silicate paint be used?

Silicate paint is particularly recommended for :

• External facades: Its durability and weather resistance make it an ideal option for the external walls of buildings, particularly in regions subject to harsh climatic conditions.
• Historic buildings: Thanks to its compatibility with traditional materials and its ability to allow walls to breathe, it is often used to restore historic monuments without damaging them.
• Damp spaces: The anti-fungal properties of silicate paint make it a wise choice in areas prone to mould, such as basements and bathrooms.

How do I choose the right silicate paint?

Before opting for silicate paint, here are a few criteria to consider:

1. Type of surface: Silicate paint is ideal for mineral surfaces such as stone, lime or concrete. It’s important to check that the wall or surface you want to paint is compatible with this type of coating.
2. The condition of the surface: Make sure the surface is clean, dry and free of synthetic paint or oil residues, as these can interfere with the adhesion of silicate paint.
3. The environment: If you’re painting in a particularly damp area or one exposed to heavy weather, silicate paint will be an excellent choice thanks to its natural resistance to mould and its durability.

Examples of silicate facade paints

Applying silicate paint: good practice

The application of silicate paint differs slightly from other types of paint:

• Preparing the substrate: It is essential that the substrate is clean and free from dust, oil or synthetic paint.
• Use of an undercoat: In some cases, a specific mineral undercoat may be required to ensure good adhesion of the silicate paint.
• Drying time: Expect a longer drying time than for conventional paints, as silicification takes longer than the simple drying of a resin-based paint.

Silicate paint can be sprayed using an airless sprayer, but it’s important to take certain specific aspects into account before embarking on the application.

1. Consistency and dilution

Silicate paints are thicker than conventional paints. It is therefore often necessary to dilute the paint with water or with a specific product recommended by the manufacturer, such as a silicate-based solution, if your airless sprayer is not powerful enough to handle this type of product without dilution. Always check the manufacturer’s recommendations on dilution to ensure optimum spraying.
If you have any doubts about using your airless machine purchased from Airless Discounter, please do not hesitate to contact us so that we can confirm what is possible.

2. Adapted equipment

Because of the consistency of silicate paint, it is often advisable to use a powerful airless device (preferably with a flow rate of around 3 l/min). Here are a few criteria to bear in mind:

• High pressure: An appliance capable of producing a pressure of at least 200 bar is needed to spray this type of paint evenly. This does not mean that 200 bars will be needed when spraying. But the airless must be able to produce this amount.
• Nozzle size: A suitable nozzle is also required. In general, a nozzle size of 0.017″ to 0.027″ (depending on the type of silicate paint, dilution and machine power) is appropriate for silicate paints.
• Filtration: Silicate paints contain mineral particles that can clog the sprayer. It is therefore important to ensure that your filtration system is effective and to clean the machine thoroughly after use. The filter size often recommended is #30 mesh (gun filters / pump filters).

3. Preparing the substrate

As with any paint application, surface preparation is crucial, especially with silicate paints. Make sure the surface is clean, dry and compatible with this type of product (mineral substrate, no synthetic paint). Airless application can then guarantee even, uniform paint distribution.

4. Precautions when applying

Because of their mineral composition and high pH, silicate paints can be aggressive to the skin and eyes. It is therefore advisable to wear protective equipment (gloves, goggles, mask) and to work in well-ventilated areas.

5. Cleaning and maintenance of the appliance

Silicate paint can dry quickly and harden in equipment, especially if it is not cleaned immediately after use. It is essential to rinse the sprayer thoroughly with water and use compatible cleaning products to prevent the silicate from clogging the system, filters and nozzle.

Spraying silicate paint with an airless device is perfectly feasible, and saves a lot of time and therefore more money, especially for large-scale projects such as facades or historic buildings. However, it is essential to choose the right equipment, the right nozzle, dilute the paint correctly if necessary and follow good cleaning practices to ensure optimum results.

Silicate paint is an environmentally-friendly, durable choice that is particularly suitable for façades exposed to harsh weather conditions. It allows walls to breathe while providing long-term protection against the elements and the growth of mould.
If you’re looking for a paint that combines performance with respect for traditional materials, silicate paint could well be the ideal solution for your project.

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