Clay clay plaster only permeable if possible

The properties and benefits of clay plaster contradict sealing. The clay can only unfold its air-conditioning and cleansing effect. There are some natural means by which the plaster surface can be treated without inhibiting diffusion. Also suitable as a partial seal are clay colors.

Few properties remain with airtight seal

Due to its sensitivity to rain and splash water, clay plaster is not suitable for outdoor use and as interior rendering material when water hits the surface directly. In living rooms, the plaster is not as resistant to abrasion as the other interior plaster types.

Some manufacturers offer seals that can remedy this disadvantage. So-called water glass can be sprayed as a transparent skin. The airtight layer closes the clay plaster like paints. This will neutralize most of the benefits of clay plaster. The following properties remain:

  • The color of clay plaster
  • Partly the heat-storing effect of the plaster layer
  • The cheap price of the raw material

All properties relating to the room climate effect and air cleaning are eliminated after the airtight seal.

Alternatives with open diffusion

Linseed oil can be used as an ideal sealant to reduce the abrasion on the surface of clay plaster. The linseed oil must be chosen pure and raw. A varnish always contains solvents that are similar in effect to other sealing seals.

To "fix" or color the surface of a clay plaster, a clay paint can be applied. It is even thinner than rolling clay plaster. When processing in multi-layer technology, the increasingly "thinner" layer model can be followed:

1. Mix flush, possibly with fiber reinforcement
2. Use topcoat for medium viscosity rolling application
3. Apply sealing topcoat with watery loam paint

With the differences of the interior plasters the choice of clay plaster must be considered well. In humid environments such as a cellar, a clay plaster can remove the typical cellar depression. Too much moisture, possibly combined with efflorescence in the masonry, the durability is not always guaranteed.

Tips & Tricks

When deciding on a clay plaster, you should consider the stress on the plaster. Heavily used wall surfaces such as in stairwells or entrance areas are not always suitable for applying clay plaster.

Product Image: Kolbakova Olga / Shutterstock

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