Plastering a wall with stucco

Many years ago, when we restored our house, I plastered my very first walls ever in our living room. I just came back from a one week training course where I learned the basics of wall plastering with lime, sand and marble powder. These walls were in a very rough condition, we had removed the old plaster, closed some holes with natural stones and here I came, ready to build up all the layers necessary before the final one could be done. Back then, I used sieved sand with lime and troweled it off. I did not know that the trowel should be made of a special steel so that no traces of troweling will be visible afterwards. My trowel wasn’t such a one and when the walls were try, lots of greyish traces became visible. It didn’t bother us very much but during the last years I became more professional on plastering walls and our house served quite often as an example for people who wanted to have plastered their walls. I did not feel very comfortable showing these walls in our living room and for that reason, I decided to redo these walls with a stucco.
Here is the recipe:

  • 3 parts of marble powder
  • 1 part of pure lime
  • 10% of the mixture casein, dissolved in soda
  • Pigments

The pigments should be dissolved in water a bit before. Not more than 30% of pigments can be added, more won’t change the colour.
Add water and mix all with an electrical whisk to a creamy consistence and apply it thinly. The support should be open (e.g. lime/gypsum/cement plaster, Fermacell).
When the layer is still a bit moist you can correct any slopes and dales with a trowel. Don’t press too hard, the stucco might come off.
At least two layers, better three should be applied.
If there are still some areas to correct after your last layer, you can do so by sanding them very lightly by hand with 180/240 sandpaper.

When the stucco is completely dry, protect it with savon noir (1 part savon, 2 parts water). You can apply it with a brush, working from bottom to the upper part.
If you want to have a brilliant surface, apply the soap only with a trowel. Beware of soap traces, you really need to work it in. That is a very long, laborious work.

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