As already mentioned, clay building and clay plasters have many positive sides. This, above all, environmental friendliness. However, clay has one major drawback — it is not resistant to moisture.
Modern technologies allow to make a clay building and clay plaster more durable and resistant to adverse factors, primarily moisture.
In the recent past, I plastered the walls of a country house, built of white brick, with clay. The floors in the house I also made from clay. Spray I made out of clay with the addition of pine needles and the finishing layer are made of a clay-sand mortar.
After drying, the surface of this plaster is not too strong — when holding the wall with your hand there is a slight sloughing of the sand. To secure the upper layer of earthen plaster made of clay-sand mortar, I treated the walls spiegasti lime in two layers. Pay attention: it spiegasti lime, as it has the property after drying to harden.
So get a solid protective layer which protects walls from moisture firmly holds the top layer of clay plaster, and besides, is not "taken" during the wall with your fingers.
However, this layer is quite thin — only a few millimeters. And this layer protects the plaster from moisture from the back side, i.e. from the side walls. So, if the wall for some reason got wet (roof drip), this layer of lime can simply flake and crumble. After drying, the walls and the plaster will have to spend processing the surface of the plaster with lime again.
You can go the other way.
In clay-sand mortar for plaster, you can add lime. Then a layer of plaster is much stronger and initially it will be less exposed to moisture.
Just need to remember that working with this solution should wear rubber gloves and avoid splashing when working on the skin and mucous membranes. Citrate tends to corrode the skin and burn the mucous membranes.
Clay-sand mortar with the addition of lime has one important feature — such a solution becomes stronger and stronger, and over the decades, its strength is not inferior to the strength of silica brick. Such a solution is impossible to use again.
Here I want to make one important remark. Spiegata lime is not to be taken literally — just put out and be used immediately. No. Immediately after the slaked lime is very hot, swells up, and then gradually cools down. However, she continues to slowly swell.
Use souhassou lime can be no earlier than a day. But better — two.If you do not bring the process of slaking lime to the end and start to work with it, the solution to which it is added, after drying, will be torn lime, growing in volume.
Today it is possible to do without the lime. For example, plaster the wall with clay-sand mortar (layer not more than 1 cm), and after the drying process the wall with primer deep penetration.
This primer penetrates into the clay-sand plaster to a depth of 1 cm, and even deeper. Processed this primer clay plaster becomes quite strong — she will not fall off when holding on its surface a hand. Even trowel for levelling of walls and ceilings the surface is not so easy to handle. So, if you want to align the surface of the clay plaster trowel, then this should be done before treatment of the surface with primer.
If the room in which the walls are plastered with clay, has a high moisture content, after treatment with clay plaster primer of deep penetration can additionally handle wall primer with properties of waterproofing.
This primer forms a waterproof layer on the wall surface, plaster is not afraid of changes in humidity in the room. However, such walls do not "breathe" like a traditional clay plaster. Here we have to compromise.
Treatment of clay walls with primer after treatment of the same walls spiegasti lime if you are going to papering the walls of Wallpaper.
If it is assumed the colouring of walls of latex paint, then on top of clay plaster you can put a thin layer satengips — just a couple millimeters, if the wall is smooth. If there is large unevenness on a clay plaster, then align the wall will have with the use of a starting putty (isohyps), and then put satengips (plaster finish), and make it up with a cheese grater. published