Is aluminum hydrophobic or hydrophilic


Hydrophob was derived from the Greek (hydro = water and Fóbos = fear) and means something like "water-avoiding"or" water-repellent ". Colloquially one also finds the word water-repellent opposite too hydrophobic is hydrophilic. Under Water repellency one understands the treatment of a rather hydrophilic surface z. B. an impregnation so that it absorbs water less easily.

Building materials or surfaces that are difficult or impossible to wet with water are called hydrophobic designated.

The Contact angle is a measured variable that should record how much a surface or a substance attracts or absorbs water. It generally divides substances into hydrophobic and hydrophilic. The border this is at 90 degrees drawn. It is determined by observing a drop of water near it Contact with the surface behaves. If the drop does not expand much and almost retains its rounded shape on the surface, it is Contact angle very large and the surface is considered hydrophobic. This repellent property can easily be achieved with a Lotus flower visualize. This even has a contact angle of over 160 degrees.

scope of application

Hydrophobic properties play a role especially when it comes to cleaning. In the case of hydrophobic plasters, the top layer is the focus of the mold defense. Additives prevent water from penetrating the pores. The resulting effect is called Film preservation designated. However, the effectiveness is limited because of the additives over time washed out become. After a while, a Repainting necessary. However, due to concerns about environmental protection, hydrophilic plasters offer an alternative to hydrophobic plasters.


In the following, the processing of the hydrophobic SAKRET colored stone plaster is described as an example:

  1. Preparation: The subsurface must not show any cracks or efflorescence and must be firm and stable. Previously applied base coats must completely dried out as well as be flat. First, the substrate is treated with the SAKRET plaster primer in order to regulate the suction behavior.
  2. Processing: The colored stone plaster itself can be processed directly. He should only be with one suitable mixer (no aluminum) are mixed. The plaster is applied with a smoothing trowel with approx. 1.5 times the grain thickness and peeled off in opposite directions. The colored stone plaster is compacted here. The plaster must not be pushed off or rubbed off. Connected surfaces must be plastered seamlessly and in one step for a uniform appearance.
  3. Follow-up treatment: The plaster must be protected from direct sunlight, drafts, frost and driving rain.

All of the above processing recommendations are non-binding. The information relates to normal use. More information is in the Technical leaflet to find.


Also Dust or dirt can have hydrophobic properties.

SAKRET offers a wide range of different hydrophobic plasters and other building materials such as grout that meet every individual need.