Efflorescence on Facades

Efflorescence on facades can ruin the aesthetic appearance of a building and compromise its durability. This issue arises due to various factors, such as moisture and the movement of water through building materials. Fortunately, there are effective ways to prevent this phenomenon, which should be considered during the design and construction phases. Below are key details on the topic.

Efflorescence on Facades – What You’ll Learn in This Article:

1. What Causes Efflorescence on Facades?
2. How to Prevent Efflorescence on Facades?
3. How to Protect Facades from Efflorescence?
4. What Role Do Proper Preparation and Application of Building Materials Play in Preventing Efflorescence?

What Causes Efflorescence on Facades?

Efflorescence on facades occurs primarily due to two factors.

1. Moisture and Soluble Salts

The presence of moisture, in any form (e.g., groundwater, rain), is a critical factor. Water contains dissolved organic compounds from decomposition processes and various mineral salts, which may originate from soil or agricultural fertilizers. These salts precipitate as water evaporates and can redissolve due to condensation moisture, given their hygroscopic nature. This recurring process often leads to material degradation due to the expansion caused by salt crystallization. Proper foundation waterproofing is essential to prevent this phenomenon, as a lack of moisture eliminates the conditions necessary for efflorescence.

2. Water Migration Through Porous Building Materials

Another major contributor to efflorescence is capillary action, where water travels through porous building materials, carrying salts that later crystallize on the surface. Efflorescence can vary in form and solubility depending on the chemical composition of the salts. Additionally, the duration of water contact with the salt source influences the occurrence of efflorescence.

Efflorescence is categorized into:

• Primary Efflorescence: Occurs immediately after the facade is built.
• Secondary Efflorescence: Appears over a more extended period.

Environmental Factors

The rate of water migration carrying salts depends on the temperature and humidity equilibrium between the substrate and its environment. Higher temperatures and humidity accelerate this process, leading to more frequent and intense efflorescence, particularly in spring and autumn.

Material Properties

The composition and hydrophobic, diffusive, and mechanical properties of the building materials used also influence efflorescence. Proper waterproofing and protective coatings that allow moisture to escape wpreventing water penetration from outside are vital for reducing efflorescence on facades.

How to Prevent Efflorescence on Facades?

While we cannot control the chemical composition of building materials or the environmental factors affecting a facade, there are steps we can take to minimize the risk of unwanted efflorescence. These actions primarily focus on selecting appropriate building materials and implementing effective waterproofing technologies—essential considerations at the architectural design stage.

1. Protect the Building Against Water and Moisture

The building must be adequately shielded from water and moisture. The more effectively we protect foundations and roofs from dampness, the lower the likelihood of unsightly salt efflorescence appearing. While this is a fundamental measure, additional steps should be taken during construction to safeguard the facade from various water sources, such as rain, groundwater, and splashing water.

2. Use Moisture-Resistant Building Materials

Choosing materials that resist moisture and allow the facade to dry quickly is crucial. Moisture-resistant materials reduce the amount of water retained in the structure, minimizing the conditions for efflorescence to develop.

3. Incorporate Traditional Architectural Features

In modern architecture, traditional elements like overhangs and eaves are often overlooked. However, these features have proven effective for centuries in protecting facades. A well-designed roof not only shields against precipitation but also reduces the time the facade is exposed to damp conditions.

By prioritizing proper waterproofing, selecting suitable materials, and incorporating protective architectural features, it’s possible to significantly reduce the risk of salt efflorescence and ensure a durable and aesthetically pleasing facade.

How to Protect Facades from Efflorescence?

The foundation of protecting a facade against efflorescence is proper waterproofing. However, it is equally important to choose the right materials for facade protection. The term "technological protection of the building" encompasses all additional surface protection measures that provide effective defense against unwanted penetration of rainwater and moisture.

Surface Impregnation or Protective Coatings

Surface impregnation or the application of protective coatings is a proven method of safeguarding facades. Using hydrophobic impregnating agents reduces the surface tension of the substrate, preventing water from wetting it. Simultaneously, the resulting coating has a microporous structure, allowing the exterior walls to breathe freely.

Recommended Products for Hydrophobization

1. Hydropor Primer
   A hydrophobic primer that enhances the water resistance of absorbent construction materials.
2. Armasil F Paint
   Especially recommended for renovating surfaces exposed to harsh weather conditions and requiring high dirt resistance. It can be applied to:
   • Mineral substrates such as concrete, traditional cement, cement-lime plasters, and thin-layer mineral renders.
   • Surfaces with synthetic-based coatings or finishes.

Benefits of Hydrophobizing Coatings

• High Vapor Permeability: These coatings allow walls to "breathe" while ensuring effective water resistance.
• Low Surface Absorption: Reduces the amount of water absorbed by the facade.
• Water-Repellent Effect: When the silicone coating is wet, it creates a water-repellent effect, causing water molecules to "bead" on the surface.

This water-repellent property protects the facade from rain and significantly reduces the accumulation of dirt.

Application Tips

Before applying the paint, ensure that the absorbent substrate is primed with Hydropor to enhance adhesion and effectiveness. These measures collectively provide durable, long-lasting protection for your facade, ensuring it remains resistant to moisture, weather, and contaminants.

What Role Do Proper Preparation and Application of Building Materials Play in Preventing Efflorescence?

The foundation of protecting a facade against efflorescence is proper waterproofing. However, it is equally important to choose the right materials for facade protection. The term "technological protection of the building" encompasses all additional surface protection measures that provide effective defense against unwanted penetration of rainwater and moisture.

Surface Impregnation or Protective Coatings

Surface impregnation or the application of protective coatings is a proven method of safeguarding facades. Using hydrophobic impregnating agents reduces the surface tension of the substrate, preventing water from wetting it. Simultaneously, the resulting coating has a microporous structure, allowing the exterior walls to breathe freely.

Recommended Products for Hydrophobization

1. Hydropor Primer
   A hydrophobic primer that enhances the water resistance of absorbent construction materials.
2. Armasil F Paint
   Especially recommended for renovating surfaces exposed to harsh weather conditions and requiring high dirt resistance. It can be applied to:
   • Mineral substrates such as concrete, traditional cement, cement-lime plasters, and thin-layer mineral renders.
   • Surfaces with synthetic-based coatings or finishes.

Benefits of Hydrophobizing Coatings

• High Vapor Permeability: These coatings allow walls to "breathe" while ensuring effective water resistance.
• Low Surface Absorption: Reduces the amount of water absorbed by the facade.
• Water-Repellent Effect: When the silicone coating is wet, it creates a water-repellent effect, causing water molecules to "bead" on the surface.

This water-repellent property protects the facade from rain and significantly reduces the accumulation of dirt.

Application Tips

Before applying the paint, ensure that the absorbent substrate is primed with Hydropor to enhance adhesion and effectiveness. These measures collectively provide durable, long-lasting protection for your facade, ensuring it remains resistant to moisture, weather, and contaminants.