Technical insights

Hydrophobic impregnation with VIMASIL ACQUA

Protect your renders!

A building’s business card is the façade and a dirty or damaged façade leaves a bad impression not to mention the building will depreciate as damage weakens the building’s fabric. One of the most serious problems for facades is water, whether it be in the form of liquid, gas or frost, water is a natural rival to mineral coatings and renders. Mineral building materials have a strong tendency to absorb water due to their porous surface structure, be it rain or damp, from both the inside or the outside of a building.

Today it is noted that most structural damage around the world is caused by water and moisture. This damage comes in many different forms but there is usually one simple remedy for all: preventative protection via hydrophobic impregnation. Efflorescence and salt damage is caused by water hydration and crystallization and in addition, water promotes the possibility of the formation and development of mould, moss, lichen etc. reducing the insulation capacity of a facade.

A dry façade will promote the reduction of energy costs and a façade with hydrophobic protection will have lower maintenance and repair costs. The façade is easier to keep clean and the value of the property is increased while heating costs are reduced.  A damp façade will restrict thermal insulation and 2% of humidity leads to an energy loss of more than 20%; with just 4% of humidity giving 50% energy loss.

Hydrophobic coating reduces water intake by approximately 80%, maintaining the thermal insulation performance of the wall at a constant high level and the hydrophobic primer Vimark® VIMASIL ACQUA maintains water-vapour permeability, ensuring that there is nothing stopping moisture from escaping through the wall, helping to create a healthy indoor climate.

Building materials that are mineral based have open-pores and contact with water causes the capillary effect. This allows large volumes of water to penetrate within a short time. Pores with a radius of between 0.1 μm and 100 μm display capillary action causing the natural transportation of water into the building material. This capillary effect can be further intensified by hygroscopic effects.  Vimark® VIMASIL ACQUA uses these capillary active forces to penetrate the mineral material. These treated pores no longer get wet yet water-vapour permeability is unaffected.

Surfaces treated with Vimark® VIMASIL ACQUA maintain their breathability, because the surface pores are not blocked by water-repellent agents based on organosilicon compounds which means, water in liquid form can no longer penetrate the capillaries that have been rendered water-repellent because a polar liquid is unable to interact with a non-polar hydrophobic surface.
The molecular structures of the organo-modified silane and siloxane are compatible with the silicate matrix of a mineral substrate. This accounts for the extraordinary efficiency of hydrophobic impregnation. The organic groups are oriented toward the centre of the capillaries and pores where the active ingredient reacts with the silicate matrix of the mineral material, reducing the surface tension within the capillaries and pores enough to stop capillary activity. The result is long-lasting hydrophobicity. The hydrophobic primer  Vimark® VIMASIL ACQUA combines high technical performance with ease of application.


  • Reduces capillary water intake by at least 80%.
  • Protection against rain and humidity thanks to a low capillary water intake.
  • A hydrophobic coating reduces water intake, without reducing water-vapour permeability


Extremely durable water protection thanks to:

  • High depth of penetration
  • Alkalis resistance
  • UV stability


  • Low water intake
  • High water-vapour permeability
  • Barrier against harmful water-dilutable salts
  • Extremely resistant to cold, heat and UV light