Polystyrene foam as well-as exterior decorating elements containing foam have been used in architecture for subsequent heat insulation of masonry. Hungarian patent application HU 213 089 describes a method of manufacturing elements for dismembering and/or decorating the frontage of buildings. According to this solution a hard plastic foam base-body is made with a particular, e. g. a cornice-like profile. This is fixed onto the required surface in the place of mounting. A net stiffening then a coating, usually plaster that forms a crust, is applied. Stiffening and crust forming sig- nificantly increase expenses. On-the-spot mounting requires sub-contractors'work of different nature, considering applying of the foam (gluing), working the net stiffening (fibreglass net) into it and forming a crust of plaster over it.

However, former foamed polystyrene materials had to be dealt with very care- fully when applied in wet environment, since the material significantly absorbs water.

Because of the fluctuation of environmental temperature and possible frost water would damage the otherwise easily mouldering material in a short time.

As a result of the latest improvements in technology, a so called extruded polystyrene foam having closed-cell structure can be produced, and due to this manufacturing process it has advantageous technical properties such as negligibly low absorption of water (-0, 2-1,0 V%/28 days), resistance against melting-freezing cycles, zero capillarity, extremely low heat transmission coefficient (-0, 026-0,032 W/m2K), and at the same time it has excellent strength properties, such as resistance to crushing (-0, 08-0,25 N/mm). On the basis of these advantageous technical prop- erties a structural system can be established that was unattainable with previously used expanded heat-insulating materials.

The aim of the present invention is to provide prefabricated panel elements at little cost, which do not require further technology on the place of application, and in most cases only fixing of them is needed. At the same time the panel should be deco- rative, embossed and weatherproof in itself. However, applying additional coating on certain parts of the panel should be made possible.

These recently recognised favourable properties of closed-cell structured foamed polystyrene material, that can be experienced in wet environment having fluctuating temperature, were utilised for accomplishment of the present invention.

The base of the system of the present invention is, that extruded polystyrene heat- insulating panels of different board-size and thickness are manufactured with different coating on the surface.

The heat-insulating panel manufactured as boards of plate format and having patterned outside surface as described in the opening paragraph is generally suitable for achieving the aim, the panel is made of closed-cell foamed polystyrene material, and structured embossed pattern is formed on the surface of the front side of the boards.

Figure 1 shows a heat-insulating panel having a surface according to the pres- ent invention, when putting in place.

Boards 2 are built upon masonry 1 according to figure 1, practically the af- fected outside surface of masonry 1 should be rough. Boards 2 are made of extruded foamed polystyrene material, which were previously manufactured as boards of plate format. An important characteristic feature of the foamed polystyrene material is, that it has a closed-cell structure so it does not absorb water. Boards 2 have two sides with large surfaces: back side 4 facing masonry 1 and opposite front side 7 facing outwards. On a surface 3 of front side 7 structured embossed pattern is formed. The pattern for example may imitate a brick wall or an ashlar wall or may contain em- bossed or concentrically protuberant elements. It is conceivable that the structured embossed patterned surface 3 entirely fills in the front side 7 of the boards 2, or it fills that only partially to achieve a bordure-like decorative surface 3. For production tech- nology reasons it could be advantageous to form the structured embossed patterned surface 3 with horizontal and vertical grooves as it is shown in figure 1 where the out- lined pattern imitates brick. In this case the required horizontal and vertical grooves can be formed by milling, applying straight feeding, or by thermal cutting, using heated cutting edge. The plates that serve as base material are available as unproc- essed plates having plane-parallel surface.

Boards 2 produced in this manner, due to the closed-cell structure of the ex- truded polystyrene foam, absorb negligibly small amount of water, the measurable absorption is approximately 0,2-1,0 vol. %/28 days.

This results in sufficient capability of resistance against melting-freezing cy- cles. The heat transmission coefficient is approximately 0,026-0,032 W/mK and re- sistance to crushing is 0,08-0,25 N/mm. The thickness of boards 2 advantageously can be 20-60 mm. Dimensioning of plates can be for example 60x120 cm, but differ- ent dimensioning is also acceptable.

Opposite the front side 7 of boards 2 containing structured embossed pat- terned surface 3 is back side 4. Generally, the surface of back side 4 is flat. However, distance pieces 6 made of the plate's own foam material can be formed as protru- sions on flat surface of back side 4 which contribute to fixing the plates onto masonry 1. Also, these protruding distance pieces 6 provide an air gap 5 of 10-30 mm be- tween masonry 1 and board 2 when building in. Cylinder-shaped or truncated cone- shaped distance pieces 6 having appropriate dimensions can be made as separate pieces, and can be fixed on the surface of back side 4 by welding or gluing during manufacture of the panel. Boards 2 are fixed onto masonry 1 using non-freezing flexible adhesive. Gluing is done in points, disposal of these points depends on the surfacing of the load-bearing member. When distance pieces 6 are provided, these pieces provide points for gluing.

When choosing the layer-thickness to be formed according to measurements of heat and vapour technology, in addition to insulation, formation of air-gap 5 is also beneficial to ventilation.

Considering the characteristics of the material, boards 2 must be protected only from UV radiation. It means that in basic design, panels are put on the market advantageously coated with paint, and after building in, painting of the front side must be repeated approximately every ten years. As suitable impregnating paint easy han- dle watery dispersion paint can be recommended.

At least certain parts of front side 7 of boards 2 having structured embossed patterned surface 3 may be coated with two component water-based synthetic resin.

This is particularly useful on parts, where the surface is subjected to danger of me- chanical damages. These parts are for example the edges and corners of the build- ings as well as the surroundings of windows and doors. As the panels are prefabri- cated, choice must include boards 2 that are also applicable to these places. So synthetic resin layer is present on outside stripe-shaped parts of boards 2 having structured embossed patterned surface 3. Advantageously this layer is applied by mechanical spraying with a thickness of 0,2-3 mm.

The covering, heat-insulating and decorating panels with different dimensions, different structured embossed patterned surface 3 and having edge and corner coat- ing provided by the system can be used for subsequent heat insulation of building constructions implementation of which had been carried out wrongly in terms of heat- insulating technique or having out of date heat bridge, and in case of new buildings legacy heat insulating materials will be replaceable or the amount of these materials will be reducible with these panels when reinforced concrete structures are being provided with heat-insulation.

An other advantage of the system is that panels may have wide-ranging pat- terns and in case of mechanical damages the damaged board is easily replaceable with a piece having the same pattern and colour in such a way that the place of re- pairs will not be noticeable.

Since boards 2 do not require solid outside covering, use of dowels and stiff- ening nets are not necessary, panels are easily fixable for example by gluing, they do not dilapidate, do not warp, so employing of them results in significant saving in costs compared to known similar heat-insulators.