Any plaster mix contains several components: a binder – lime, cement, gypsum or synthetic resins, as well as a filler and special additives. The characteristics of the plaster depend mainly on the properties of the binder.
Lime plasters
These are moisture-resistant universal mixtures that can be used for both external and internal work. In its pure form, lime plaster dries for a long time and has low strength. To reduce the drying time, gypsum is added to the mixture, and to increase the strength – cement.
Lime plasters are used in restoration work to repair old buildings where the walls are already plastered with lime. The composition is applied in several layers, the thickness of each is no more than 20 mm. They are rarely used for finishing apartments and private houses.
It is believed that lime gives the material antiseptic properties; mold and mildew do not appear on walls plastered with lime. This can be useful when plastering walls in storage rooms and cellars.
Cement plasters
Cement gives the plaster compositions based on it high water resistance and strength, so they can be used not only in residential premises, but also in basements, on facades, when arranging swimming pools.
Cement hardens slowly – up to 12 hours, shrinks during hardening, gains strength in several weeks – this must be taken into account when planning work. It gains 100% strength in 28 days. According to SNiP 3.04.01-87, when laying a layer thicker than 30-40 mm, cement must be reinforced with mesh.
Gypsum plasters
These are the most convenient materials to work with, so they are most often chosen for finishing residential premises. Gypsum plasters are plastic, level well, do not flow on vertical surfaces, they can be applied in a layer of 5 to 50 mm at a time. After application, they quickly set – within 2-3 hours. The time for a 15-20 mm layer to dry completely is about 5-7 days.
The disadvantage of gypsum plasters is that they are not moisture resistant. Therefore, without protection from water, they cannot be used in damp rooms – bathrooms, toilets, basements.