Field of Technology

Construction; insulation for a building envelope; insulation of contact facades (ETICS - External Thermal Insulation Composite / Compact System or German WDVS - Warme- Damm-Verbund-System); thermal insulation panels.

Technical Problem

The technical problem, to which the present invention offers a solution, represents an implementation of facades, produced on the basis of moisture-rich surfaces (construction moisture, capillary rise moisture on periphery walls, ground water or rain water or other types of moisture). In this case the technical problem deals with how the moisture runs through the whole facade surface into the surrounding area.

State of the Art

The facade is not merely a protection or a building decoration; it simultaneously provides a pleasant room climate, reduces energy consumption and therefore protects the environment and reduces the emissions of the C0 ₂ equivalent. It is hence a fundamental life investment, which provides savings on a daily basis.

The contact facade systems (ETICS) are effected by applying the visible roughcast and paintwork finishings directly on thermal insulation without any intermediate air layer whatsoever and neither any other layer. Thermal insulation panels are glued, often with special anchors, to the periphery wall, usually made from brick, reinforced concrete, foam concrete and similar materials. From the constructional and physical point of view the solution is not optimal, as excellent water-tightness and vapour permeability can hardly be expected from the finishing layers.

For the purposes of this patent application, the contact insulation facade is a system of external thermal building envelope, in which case thermal insulation is glued or mechanically fastened directly on the external wall; upon thermal insulation we apply basic and finishing decorative roughcasting, giving monolithic properties to the facade without any contact of fissures, joints or other, similar problems. Primarily, these facades cut heating costs and simultaneously offer elegant, rich-in-design surfaces, providing expressive potential to forms and colours; they also combine the latest experience and know-how in technical development, construction engineering, mechanics, construction physics and chemistry.

Because in most cases of contact insulation facades additional thermal protection represents additional financial investment into increased thermal insulation thickness, this means the best energy-saving investments by far. According to the experience, each additional centimetre of thermal insulation represents a mere 2% investment increase into the whole facade system, together with all the materials, work and a rent of facade scaffold. All other measures (i.e. heating systems, solar collectors, window and door technology and the like) require a substantially bigger investment and normally have a considerably shorter operational life.

In the past the technical issue stated herein was handled by applying partial solutions. The solution was demonstrated as an installation of thermal insulation panels with high vapour permeability, which would potentially solve the technical issue; however, the thermal insulation panels alone cannot be left on the facade, therefore the solutions offered fail to check and test the impact in the whole system. Furthermore, all the systems currently in use do not provide random distribution of redundant vapour under facade cladding (only vapour transmission locally under the area of individual holes is facilitated). The solutions known were used by a variety of companies, e.g. Sant Gobain, Weber, Terranova, the Kremsnita insulation product, www.weber-terranova.si, Bau Mit, Baumit Open insulation product, www.baumit.si

The Description of a New Invention

The notched insulation panel, the procedure to equalize vapour pressure and the installation procedure solve the technical problem of the implementation of facades, produced on the basis of moisture-rich surfaces (construction moisture, capillary rise moisture on periphery walls, soil water or rain water or other types of moisture). According to the invention, the solution includes deep notches into the panel side facing the wall. Following the implementing solution, the notches predominantly run in one direction or principally into several directions, preferably two, which mutually run in approximately perpendicular directions.

The notches herein have two favourable effects. The first one is vapour transmission under the panel surface, consequently balancing vapour diffusion and preventing the situation of vapour passing through more intensely at one point and less intensely at other. The second favourable effect is adapting the panel to uneven spots in the surface. Insulation panels made of polystyrene, polyurethane or other insulation materials make it possible for the panel to locally force its way on the spot facing the surface, whereas on the other side (facing the opposite direction) it actually remains smooth-faced.

At the edges, the panels are optionally facing the surroundings, which do not only provide diffusion, but in some cases convection of vapour from the surface and intense drying.

The notches are as deep as a 15% average thickness of the facade panels, on a primary basis more, comparatively exceeding 40%, but not exceeding 85% of thickness and on a primary basis not exceeding 75% of thickness. By decreasing the notch depth, the vapour transmission reduces along with the speed of equalizing vapour pressure, whereas increasing the notch depth decreases the panel strength. The figures stated represent a compromise between both of the mechanisms described herein.

By using new panels we avoid the trouble, which is common in cases of freshly made constructions with increased quantity of inherent or absorbed moisture; moreover, we avoid improper implementations with increased level of (condensation) moisture content or, in cases of rehabilitating the existing buildings, having capillary or other type of moisture. Furthermore, this system provides a significantly better protection against eventual local wall moistening, resulting from installation damage, water discharges and occurring as a consequence of minor mistakes made in constructional and physical planning or implementation. As in this way moisture may enter the surrounding area without preliminary stopping or accumulating within the wall, the panels, following the guidelines of the new invention, can be used to dry out the structure. The drying mentioned herein is neither quick nor particularly intense, but it is continual in the sense of providing safe planar vapour permeability.

We therefore provide equalization of vapour pressure within the closed facade and simultaneously restore regular vapour transmission along the surface through external constructional complexes into the surrounding area.

Following the new invention the facade panel can be used as an alternative for all current systems of contact insulation facades on the basis of expanded polystyrene (EPS) or STYROFOAM, as the surface of a new panel on the side of the facade end is completely the same as current panels, whereas the reverse side of the panel contains additional ventilation channels running vertically and horizontally to the surface of the wall, providing ideal vapour pressure equalization. Due to deep notches and channels the moisture transmission coefficient 'μ' is reduced (from 35 to less than 18, naturally depending on the size, depth and arrangement of the ventilation channels).

Another great advantage of this innovative panel is its amazing flexibility (reduced stiffness), providing good adaptation to uneven surfaces. As thickness of facade panels has recently increased, mostly because of energy-saving reasons, the new, hugely flexible panels prove to be advantageous precisely in such cases.

Equalizing vapour pressure and therefore free vapour transmission from the structure into the surrounding area is therefore facilitated. The structures can be dried out without retaining or even accumulating water vapour. Because the notches are placed at the wall side, it is possible to equalize vapour pressure behind the facade, despite the fact that facade adhesive is applied to that particular spot. Equalization is possible via continuous deep ventilation notches (channels) on the reverse side of the innovative insulation panel. Such facade is considerably more resilient to damage, caused by local condensation of water vapour. This system provides water vapour equalization behind facade layers and consequently makes it much easier for the condensed moisture to exit through the entire surface of the facade and enter the surrounding area, due to equalization of internal vapour pressure with external vapour pressure. The part of the structure with increased moisture content can be effectively dried by diffusely open contact facade.

It provides the implementation of the facade on sensitive surfaces and freshly-made surfaces; it can be used during rehabilitation procedures and, because of the capillary moisture in the walls it facilitates the transmission of rain water or ground water; it can be used even in cases of damaged wiring installation or damaged surfaces and on surfaces from foamed concrete or lightweight concrete, perlite or in other similar cases.

The possibility of using thick facade panels, particularly the insulation panels, is big. Facade panels have recently become increasingly thicker, mostly because of energy- saving reasons and to reduce environmental nuisance. Therefore, the facades measuring 20, 30 cm in thickness or event more, are not a rare occurrence. It is precisely because of such thickness that we need a more surface-friendly panel that adapts easily; this, however, is more difficult because of the increasing thickness, making the panels too stiff.

Following this invention, reduced stiffness of individual panels insures amazing surface adaptability. This helps us avoid trouble occurring after the installation, in case of extricating outside the flat surface of the facade, in case of panel curvature, placing or moving the position of the panels prior to binding of the adhesive mortar and in case of easier levelling during the installation phase. The flexibility characteristics are so distinct that the panel can easily adapt to irregularities, round surfaces and other similar surfaces.

Numerical simulations and practical measurements have shown that a 3% fall of the thermal conductivity value is to be expected at the most (thermal conductivity is denoted with a Greek letter 'λ' (lambda), unit: W/(m K) ). Vapour permeability ( μ ) of the panel, following this invention, is less than 18 and depends on the size, depth and arrangement of the ventilation channels, whereas this value in commonly used panels is 30 to 35.

After the installation, there is no flow of air down the notches and consequently thermal conductivity is not increased. Both in the manufacturing and installation procedure, the notches are normally indented according to adjacent panels (it is both impossible and useless to install facade panels by continuously applying notches between adjacent panels). By using facade system following the guidelines of patent protection, airflow is not present; there is only equalization of increased vapour pressure. Properly implemented facade is closed from all sides, from below and above and around all window and door openings and other fissures. Despite vapour-equalizing layer we can make an airtight wall in transversal and longitudinal directions, which is extremely important for low-energy (LEH), near-0-energy and passive houses (PH). The newly developed system can by no means be considered a system of »rear-ventilated facade«, i.e. the facade which would be ventilated behind its thermal insulation from the external side of the wall. In this case thermal insulation would both practically and numerically drastically decrease.

Figure 1 shows a facade panel, representing the panel front not facing the surface. The notches, facing the surface, can be clearly seen. Figure 2 shows a facade panel revealing the panel front, lying against the surface, particularly the external wall. The notches, which run in several directions following the implemented case, are clearly seen. Both figures show arrows, denoting directions of vapour transmission down the notches which function as narrow channels (regardless of their potential capillary characteristics because of the small transversal section).