Gypsum is one of the oldest building materials

Gypsum is one of the oldest building materials. Under natural conditions, it is found as crystalline calcium sulfate salt with two water molecules . After appropriate treatment – chopping , grinding and roasting – gypsum becomes viscous material . After contact with the appropriate amount of water required for the bonding process , it returns to its original shape. After drying of the plaster is resistant to compression and is relatively easy . Worse is its tensile characteristics . All its mechanical properties deteriorate when wet.

Thanks to its unique qualities , gypsum has the ability to adjust the relative humidity : it quickly absorbs moisture and quickly compared with other materials , dries , giving moisture to the surrounding air . With this premise , built using plaster, have a distinctive microclimate in which a person feels fine .

Modern chemistry is capable of , changing the structure of the material , they reduce the absorption of water, but then much more expensive product .

Other gypsum role associated with the presence within its structure of two molecules of water, is that on one hand the gypsum element in direct contact with the fire , can keep the temperature for a long time of about 120 * C, another duration of this effect depends on the thickness of the plaster layer and the intensity of the fire. This property plaster making it one of the cheapest fireproof materials.