Mineral renders - dry powdered, cement-based with added lime and 'dry' polymers to modify the natural properties of the mortar. Unlike traditional renders, it is very thin and can not function properly without organic additives, which are responsible for its working properties and hydrophobicity. Mineral render contains mineral fillers and texturizers. It provides high vapour permeability. Consequently, this type of finishing coat is recommended for systems, where thermal insulation requires low diffusion resistance from the finishing layer - mineral wool and high fire resistance - non-flammable.
The natural microporosity of mineral render allows an excellent flow of the thermal pressure generated by the heating of the facade. The microporosity of render is an advantage, but also a drawback due to the relatively high water absorption and low impact resistance. The problem of high absorbency is usually limited by painting mineral render with silicate or silicone paints.
In conclusion, this type of render is highly recommended for mineral wool insulation and parts of facade above the areas exposed to the mechanical damage and deflecting rainwater - plinths, low ground floor.
Acrylic renders - the most popular type of render. In this case, a binder is a dispersion of synthetic resins. Acrylic renders are flexible, structurally compact, hydrophobic (low absorbent) produced in the form of a ready-to-use colour paste that can be used straight after mixing. The chemical peculiarity of this type of prendering makes it possible to create a practically unlimited palette of colours. This type of render is insensitive to changing weather conditions during the application. They dry and bind by evaporating water from the system and creating physical bonds with the ground.
In conclusion, acrylic renders are universal and can be used in every area of the facade. They are easily washable, resistant to damage and overgrown by algae and fungi when adequately protected.
Silicate renders - ready-to-use pre-coloured render, which can be used straight after mixing. Made of potassium hydroxide with synthetic resins, that reduce water absorption, responsible for initial bonding and colour stability. Mineral filler (potassium hydroxide) with a strong alkaline reaction (very high pH) naturally increases the resistance of silicate plasters to algae and fungal growth. Render also belong to the group of mineral renders due to the properties imparted by the mixture of silicate and polymer binders that adhere by evaporation of water. Also chemically, because of the absorption of carbon dioxide from the environment to form a water insoluble structure. Because of the pigmentation with only organic pastes, the palette of colours is based on bright, pastel colours without vivid undertones.
In conclusion, silicate plasters bond well to mineral substrates (including silicate render primers reinforced with insulation), are highly vapour permeable, resistant to environmental factors. They are sensitive to weather conditions during the application process, but still very functional and durable.
Silicone renders - the latest generation of facade renders in which the binder is mainly based on emulsions of silicone resins and polymer dispersion. This type of finishing coat, gives properties such as flexibility, hydrophobicity and vapour permeability in the most effective way. From a chemical point of view, silicone renders should be graded between mineral and organic plasters as they form mineral compounds. Moreover, they bind to the base with physical bonds, making the coating flexible and widely resistant to temperature changes. Silicone plaster is a combination of the most beneficial features of mineral and organic textured renders, its main strengths are a broad spectrum of colour, very good application properties and the ability to use on a wool, polystyrene EPS, phenolic boards and cement carrier boards. Manufactured in the form of a ready-to-use colour paste that can be used straight after mixing.