- Two main finishing technologies
- Special types of finishes (brick, thermal panels, etc.)
- Types of ventilated facades
- Materials for plastering
- Compliance of the facade system with the wall material
Facade decoration has not only a decorative function, it serves as the main element of thermal protection of the building and protects the walls from the harmful effects of the outdoor environment. In this review, we will compare various facade materials, indicate the real area of their application and the main qualities..
Two main finishing technologies
Facade decoration today is a completely separate industry, which includes both the development and production of modern building materials, and a carefully thought-out procedure for performing work. No matter what type of facades we are talking about, for each of them there is a well-developed technology, due to which the durability of the finish is from 30 years, provided that the recommendations of construction engineers are followed.
In general, all types of facade finishing can be divided into two categories, one of which is hinged ventilated facades (RVF). Their essence is quite simple: a rigid cladding is attached to the frame subsystem, in the role of which siding, porcelain stoneware or metal-composite panels can be used, while a limited air circulation remains under the outer shell. Such facade systems are used if there are mineral heaters in the thermal protection belt that are sensitive to moisture accumulation. Due to the blow-through of the thermal insulation, effective removal of condensate into the external environment is achieved, however, due to the high complexity of the system, the cost of such finishing is considered one of the highest.
The second category includes all types of facade finishes that are associated with the performance of plastering works and is called “wet” facades. The cake of such a building cladding consists of insulation, a basic reinforcing and decorative layer, which are rigidly fastened to each other. The installation of wet facades seems simple, but in reality, the quality and durability of such a finish largely depends on the qualifications of the workers. However, the costs of attracting professional finishers are more than offset by the relatively low cost of the materials used and the improved performance of the building’s weather protection..
Special types of finishes (brick, thermal panels, etc.)
There are also finishing methods that cannot be attributed to any of the main categories. For example, facing with hollow bricks – one of the most popular methods for arranging facades of the last century – is still successfully used today. On the one hand, such a facade is ventilated, however, the brick shell has self-supporting properties and therefore cannot be considered hinged.
Another special case is the use of sandwich panels for finishing. This is one of the most modern technologies, characterized by a high speed of work and a long service life. And yet, such a facade system is very limited in application, primarily due to the insufficient widespread distribution of high-quality composite panels..
Of the specific finishing materials, one cannot but mention thermo-efficient panels with clinker tiles. In terms of design, such a system is very similar to an illegal armed group, however, the insulation is located directly under the cladding layer, and the air gap is not ventilated, playing the role of a thermal break. There may be no air at all, in which case the system approaches a wet facade, although plastering work is not performed directly during installation.
Types of ventilated facades
The load-bearing part of the IAF remains unchanged regardless of the cladding material used. The subsystem includes post profiles that are attached to the load-bearing layer of the wall using straight hangers or console brackets. The material of the subsystem can be galvanized and stainless steel, wood, less often aluminum and plastic products. A high degree of unification of the facade frame system significantly simplifies the calculation of the existing loads and thermal permeability.
The list of materials for cladding is very diverse:
- Siding is a sheath made of long metal or plastic panels with vertical or horizontal orientation and locking joints to prevent moisture seepage. As a rule, siding has a floating fastening system to compensate for thermal deformations.
- Planken is a type of wood siding that can have a different cross-sectional profile and can be mounted both on lock joints and with the formation of gaps between the panels.
- Facade tiles are usually made of porcelain stoneware or fired ceramics (terracotta). It is fastened to the subsystem with clamps and is characterized by a high dead weight. Rarer varieties – panels made of fiber-reinforced concrete, natural granite or slate.
- Facing panels. They can have a shell made of aluminum or roofing iron with a polymer coating. Panels are made in situ from sheet materials by milling a V-shaped groove along the fold line, followed by the formation of a parallelepiped without a bottom. Fastening with self-tapping screws or blind rivets.
- Magnesite and fiber cement boards. This is the most specific type of cladding designed for applying decorative plaster to the surface of illegal armed groups..
Materials for plastering
Wet facades are applied over polymeric insulation such as XPS, PUR or PIR in the format of slabs with grooved edges, rigidly and closely attached to the load-bearing layer of the wall. Less commonly used mineral wool of a special grade, which has a high density and has a compacted surface layer.
A so-called base reinforcing coating is applied on top of the insulation. It includes technical façade plaster reinforced with one or more layers of fiberglass mesh. The task of this element is to form a strong crust that protects the insulation from mechanical damage and is able to withstand seasonal fluctuations in the supporting structure. Base reinforcement layer provides pre-leveling to reduce decorative material consumption.
Cement, cement-polymer, latex, silicate and acrylic decorative plasters can be used as a topcoat. Each type of this material has a unique surface texture. The plaster can be painted in mass or subsequently covered with facade paint. In the most basic wet facade systems, paint is applied directly to the base plaster after it has been carefully leveled.
The main feature of plaster facades is the difficulty of calculating thermal conductivity and moisture accumulation. The materials of the outer layers should not interfere with gas exchange between the insulation and the outside air, while it is required to ensure the hydrophobicity of the decorative coating. If the facade is arranged without preliminary calculations, moisture may accumulate between the layers, which has a destructive effect and leads to swelling of the coating or the formation of cracks. Also, a prerequisite is the use of special primers before applying each layer..
Compliance of the facade system with the wall material
Which façade is better? It is impossible to answer this question unequivocally, each of the finishing technologies has strengths and weaknesses. Basically, there are two selection criteria: the required aesthetic qualities and compatibility with the material of the building envelope..
For hinged facade systems, the structure of the wall material is of primary importance; it must ensure reliable fastening of the supporting frame. In terms of the degree of conformity to the thermophysical characteristics, RVFs are the most universal, for the most part they do not allow deterioration of the properties of the insulation and its irreversible damage under the influence of moisture, although in terms of general indicators of thermal efficiency they are still inferior to plastering.
Wet facades, in fact, are self-supporting, but provided that the surface of the walls has good adhesion for gluing insulation. As a rule, using the technology of wet facades, buildings are decorated with bricks, cinder blocks and gas silicate blocks, that is, any stone buildings. This method is least suitable for finishing wooden and frame houses..