External wall thermal insulation – necessity of modern housing
The need for good thermal performance of buildings is popular among the general public because of its effects of saving money by reducing energy consumption. On the other hand, the comfort in the buildings in times of extreme outdoor temperatures is of inestimable value, but temperature control is the main reason for thermal problems when using a building.
The problems related with the presence of unwanted moisture in the building, mirrored in mould on the walls, are caused by absence of thermal insulation, bad installation of the thermal insulation or insufficient thermal insulation. The essence of the problem is the condensate which is formed when cold air comes in direct contact with warm air inside the wall.
In cases of wall surfaces made of compacted material with good thermal conductivity, the moisture and mould cover the entire surface of the walls. If the presence of moisture and mould is limited only to one part of the wall surface (usually in the structural elements made of reinforced concrete), it is an indicator that there has been an omission in the installation of the thermal insulation of the building, i.e. these parts of the building have not been properly covered. Problems with presence of moisture and mould also appear upon reconstruction of residential buildings and business facilities when the old windows are replaced with new ones, which have a significantly reduced heat transfer coefficient. Another example of this type are the fitted wardrobes fixed to a façade wall in buildings which prior to the interior design had functioned properly. These examples serve as evidence to prove that the presence of thermal insulation is not the only pre-condition for ensuring that the building has good thermal performance. Furthermore, the thermal insulation should have the proper dimensions and should be properly installed in order to be able to perform successfully its function as part of the system of the building.
A solution to all the problems in terms of thermal performance is to install thermal insulation on the outside of the building. It will enable the envelope to prevent the external impacts and to ensure independent functioning of the interior of the building. Main elements in the thermal insulation of buildings are the thermally insulated façade systems.
THERMALLY INSULATED facade SYSTEMS
External wall insulation systems make up the largest part of the thermal insulation of a building. For proper design of the system, it is necessary to provide for thermal insulation panelling of the entire envelope with expanded polystyrene, especially of the structural elements made of reinforced concrete. The dimension and density of the expanded polystyrene for installation of the thermal insulation façade system is part of the thermal calculation. Nowadays, apart from the expanded polystyrene, hard-pressed stone wool is applied as an insulation material in the thermal insulation façade systems.
Installation of external wall thermal insulation by using ADING’s materials
The external wall thermal insulation system can be applied on wall surfaces made of ceramic blocks, reinforced concrete or on rendered surfaces. For the application of the façade system, it is necessary for the surface to be sound, strong, dry, grease-free and dusted and without unstable spots. If there are damages, they should be removed until obtaining a sound substrate and the surface should be repaired by applying REPARATUR MALTER F – polymer-cement repair mortar reinforced with fibres. The thermally insulated façade system should be installed at temperature between 10˚С and 35˚С, under dry weather conditions (with relative air humidity up to 60%).
The installation of the thermally insulated façade system begins by fixing the thermal insulation blocks with STIROKOL P polystyrene adhesive– which can also be used for fixing stone wool. If the surface on which the thermal insulation is to be applied has uneven spots, it should be expected that more adhesive will be used for fixing the thermal insulation blocks. When fixing the thermal insulation, it is necessary that the blocks be lined up and dense in order to reduce the presence of open joints (thermal bridges). The installation of the blocks should be done by applying the bricklaying method and avoiding any possibility for the joints to be in line, whether horizontally or vertically. Special attention should be paid to the façade openings (windows and doors) where the joints of the blocks should not be in line with the edges of the opening. STIROKOL-P can be applied by dotting or by spreading the adhesive over the surface. Application by dotting means to apply a thicker layer of adhesive along the frame of the block and three dots in the middle area of the insulation block. Surface application means spreading STIROKOL-P over the entire surface by using a notched trowel with notch size 15 mm. For additional safety, after the thermal insulation has been fixed and the adhesive has cured, there is a possibility for the thermal insulation to be additionally mechanically fixed to the substrate by bolts which enable uninterrupted thermal insulation. The fixing of one thermal insulation block (50/100 cm) requires minimum five bolts.
After installing the insulation panels on the surface, it is necessary that the thermal insulation blocks be connected to each other and levelled. This is achieved by applying a skim coat on the façade in two layers. The skim coat is applied on the thermal insulation blocks by applying STIROKOL-P which is used for this purpose as well. Between the two layers of STIROKOL-P, an alkali-free grid should be placed which at the edges of the façade ends with a coving strip for fine formation of the corners. The alkali-free grid at the openings of the façade is placed in a diagonal pattern.
The surface on which skim coat was applied with STIROKOL-P should be covered by a layer of PRIMER V applied on a dry substrate. The primer provides a better bond between the substrate and the new layer of decorative mortar. Depending on the desires and possibilities of the investor, the decorative mortar can be acrylic-based – HIDROFAS or mineral-based – ADINGFAS.
The decorative acrylic-based mortar HIDROFAS is a watertight ready-mix render in colour which can be applied on the primed surface with no previous preparation. It is available in several variants: with coarse-grained structure as HIDROFAS Z or with a uniform structure which depending on the desired texture (roughness) is available in three different grain sizes: HIDROFAS 1 mm, HIDROFAS 1.5 mm and HIDROFAS 2 mm.
The decorative mineral-based mortar ADINGFAS is white mortar in the form of powder which after a simple preparation (adding water) is applied over a primed surface. It is available in several variants: with coarse-grained structure as ADINGFAS Z or with a uniform structure which depending on the desired texture (roughness) is available in three different grain sizes: ADINGFAS 1 mm, ADINGFAS 1.5 mm and ADINGFAS 2 mm. The colouring of the mineral-based decorative mortar is carried out by covering the surface finish with the façade paint ADINGKOLOR F.
When performing works on a building, apart from the functionality of the premises, attention should be paid to details and to the materials that are going to be applied since they ensure the normal functioning of the building, its rational maintenance and its longevity.