EP2775062A1 - Device for thermally insulating a building wall from the outside and method for using such a device - Google Patents

Abstract

The device has a rigid and impermeable insulation layer (3) comprising a contact face (31) adapted to be fixed on a wall (1) and an external face (32) opposed to the contact face, and a rigid, perforated facing plate (6). Parallelepiped spacers (4) are fixed on the external face to maintain the facing plate remote from the external face and to place an air strip (7) between the facing plate and the external face of the insulation layer. A layer (8) of a granular insulation material (9) i.e. porous granular insulator, is provided between the rigid insulation layer and the facing plate. An independent claim is also included for a method for outer thermal insulation of a wall of a building.

Description

The invention relates to a thermal insulation device from the outside of a building wall, in particular applicable to walls and roofs, and more particularly to such a device that also makes it possible to protect the wall and the insulation against deterioration by climatic aggressions such as sun, wind, snow, rain, etc. The invention also relates to a method for producing and implementing such a thermal insulation device.

There are two main techniques for insulating a building. The first is to provide on the inner face of the walls or roof of the building the laying of insulating materials such as glass wool, in greater or lesser thickness for the desired coefficient of thermal insulation. However, it is advisable to leave an air gap between the inner face of the wall or roof and the layer of insulation, and to cover this layer of insulation, on its inward side of the room to be insulated, by a coating such as plasterboard to maintain the insulation and ensure a proper finish of the wall. In this case, the thickness of the insulation device encroaches on the living space of the parts to be insulated.

The second technique is to isolate the walls of the building from the outside, that is to say to apply and fix on the outside walls and roofs a layer of insulating material. However, in this case, the insulation is subjected to climatic aggressions which can deteriorate it quickly.

The present invention therefore aims to provide an insulation device from the outside of the walls of a building that has improved resistance to climatic aggressions.

The invention also aims to provide such a thermal insulation device which is adapted to isolate walls or roofs without major modification of the device.

The invention also aims to provide such a thermal insulation device that can be installed over or instead of an existing roof.

The invention further aims to provide such a thermal insulation device which has a high thermal inertia.

The invention also aims to provide such a thermal insulation device which has an improved ecological impact.

• une couche d'isolant rigide et imperméable comportant une première face, dite face de contact, adaptée pour être fixée sur ladite paroi, et une deuxième face, dite face externe, opposée à la face de contact,
• une plaque de parement rigide et perforée, et
• des entretoises fixées sur ladite face externe et adaptées pour maintenir ladite plaque de parement à distance de la face externe et pour ménager une lame d'air entre ladite plaque de parement et la face externe de la couche d'isolant rigide.

To this end, the invention relates to a thermal insulation device from the outside of a building wall, characterized in that it comprises:

• a rigid and impervious insulating layer comprising a first face, said contact face, adapted to be fixed on said wall, and a second face, said outer face, opposite to the contact face,
• a rigid and perforated facing plate, and
• spacers fixed on said outer face and adapted to maintain said facing plate away from the outer face and to provide an air gap between said facing plate and the outer face of the rigid insulation layer.

The insulation device according to the invention uses a rigid and impermeable insulating layer formed for example of polystyrene or expanded polyurethane plates, of thickness calculated as a function of the desired thermal resistance, itself dependent on the location of the the work. This insulating layer may be made in one or more thicknesses made integral by gluing, for example, when the wall to be covered has asperities where the first thickness of insulation allows to equalize the surface and the second to achieve a continuous coverage . The insulating layer is fixed by its contact face on the wall to be insulated, directly or after interposition of a vapor barrier according to the nature of the wall to be insulated, if necessary fixed on nailed, glued battens or screwed on this wall. The installation of a rigid and perforated facing plate, for example one or more sheets of perforated metal sheet at a distance from the outer face of the insulating layer, protects the latter from the main attacks. climate. A perforated sheet metal plate allows the surrounding air to circulate on either side of the plate and maintains a much lower surface temperature than that of a solid plate when exposed to direct sunlight. In addition, by choosing a sheet having a rate and appropriate perforation dimensions, the insulating layer is shaded and subtracted from the influence of direct sunlight. For example a perforation rate of the order of 20% allows sufficient air circulation while retaining 80% of the surface of the insulator in the shade. In addition, depending on the latitude of the location of the structure and the exposure of the wall to be insulated, it is possible to calculate the optimum distance between the perforated wall plate and the insulation so as to limit the time continuous exposure of each point of the surface of the insulation layer. For example, a face plate with perforations of 5 mm and placed at 150 mm from the outer face of the insulating layer limits the continuous exposure of the insulator for a horizontal wall to 7 minutes. level of the equator.

Thus, a rigid and perforated facing plate makes it possible to limit the degradation of the insulating layer under the effect of exposure to the sun. It also allows, thanks to its rigidity, to protect the layer of insulation against wind energy and the direct impact of rain or hail. The perforated siding plate is a protective layer in the event of snow by supporting the weight of the layer of snow, minimize the risk of slipping it while allowing the evacuation of meltwater.

Advantageously and according to the invention, the thermal insulation device further comprises a layer of granular insulation between the insulating layer and the facing plate. According to an advantageous characteristic, the granular insulator is a porous granular insulator, for example consisting of expanded clay balls or pumice gravel. By adding a layer of granular insulation between the insulation layer and the perforated facing plate, the path of penetrating water through the perforations of the facing plate is changed. The direct runoff on the insulation layer is minimized and the time taken by the water to reach the Rainwater evacuation system is increased, minimizing the risk of waterlogging and the risk of overflowing and flooding that may result. Thanks to this layer of granular insulation, and particularly when it is a porous granular insulator, the thermal insulation device according to the invention allows a regulation of the water flow rates by promoting a retention of water in the layer of granular insulation without having an adverse impact on the performance of the rigid and impermeable insulating layer that supports it. In addition, the delayed release of the amount of water retained in the granular insulating layer, whether by runoff or evaporation, contributes to maintain a moderate temperature on the outer walls of a construction thus equipped and, particularly under Tropical climates with fast alternations of precipitation and strong sunshine, allows a natural air conditioning of the environment of the structure. The layer of granular insulation also contributes, depending on its nature, to fix certain pollutants contained in the precipitation water and improves the quality of the discharged water. Even when used in dry climates, the granular insulating layer makes it possible to increase the overall thermal inertia of the insulation device according to the invention and therefore to improve its performance. Preferably, the granular insulator used comprises expanded clay beads which may have, depending on their finish, either a good porosity or an impermeable surface. In addition, the density of the expanded clay balls is relatively low, of the order of 500 kg / m ³ , which makes it possible to use them on the roof without excessively increasing the coverage, and exempts, subject to certain reservations, consolidation or modification. the existing support structure. Alternatively, volcanic materials such as pumice or pozzolan can be used.

Advantageously and according to the invention, the granular insulator is contained in at least one nonwoven synthetic textile bag, in particular needle-punched geotextile. In order to maintain in position the granular insulating layer, in particular on vertical walls such as walls or having a non-zero slope such as roof panels, the insulation device according to the invention provides for the use of rotproof synthetic textile bags, for example needle-punched polypropylene geotextile felt, which have the advantage of being naturally porous and can easily be made in many dimensions by folding and thermo-welding of edges between them.

Advantageously and according to the invention, each bag has a substantially cylindrical shape, with an axis defining an installation orientation and a diameter less than or equal to the distance between the outer face of the insulation layer and the facing plate. . The simplest form for bags containing the granular insulating layer is in the form of substantially cylindrical strands obtained by folding a textile rectangle along its length and welding its long edges between them. One of the short edges is then closed by thermo-welding and the bag is then filled with granular insulation. Preferably, the bag is only 80% filled to allow it to be crushed against the rigid insulating layer during placement.

Advantageously and according to the invention, each bag has a substantially parallelepipedal shape and comprises partitions, said partition walls, rectangular, parallel and regularly spaced whose long edges define an installation orientation and are attached to the main faces of each bag so to maintain between said main faces a distance less than or equal to the distance between the outer face of the insulation layer and the facing plate. In this embodiment, the bags are in the form of rectangular cushions whose thickness is maintained substantially constant by interlayers. The bags are made from two rectangles between which are welded partition walls forming parallel cells and which is welded to the edges parallel to the partitions and one of the perpendicular edges. The bags are then filled with the edge perpendicular to the partitions not yet welded so as to distribute substantially equally the granular insulation in the cells and the bag is closed by thermo-welding of the last edge.

Advantageously and according to the invention, at least one of the main faces of each bag is perforated. Although the geotextile felt used to make the bags is naturally porous, it is preferable to provide additional perforations to promote the entry of precipitation waters in the granular insulating layer. Preferably, it is the face of the bag facing the facing plate which is perforated in the case of a parallelepiped bag.

Advantageously and according to the invention, each bag is fixed on the rigid insulating layer so that its installation orientation is orthogonal to a line of greater slope of the insulating layer. In order to avoid excessive settlement of the granules of the insulator under the effect of gravity, the bags are fixed on the rigid insulation layer so that their largest dimension is orthogonal to the slope line of the wall . Thus, for a wall or a roof, the axis of the cylindrical bags or the direction of the partition walls of the parallelepiped bags is generally horizontal to avoid settling of the granular insulation at one end of the bag.

Advantageously and according to the invention, the rigid insulating layer comprises on its outer face an anti-depression coating on which the spacers are fixed. In order to avoid punching of the rigid insulation layer, either by the weight transmitted by the spacers or by the manipulations and movements of the workers during the installation of the insulation device according to the invention, it is preferable to provide an anti-sinking coating on the surface of the insulation of the rigid insulation layer. Such a coating is often integrated from the manufacture of the insulation that is delivered glued on one side to a rigid plate ensuring the rigidity and protection against depressing insulation. In the case where the anti-sinking coating is not originally part of the rigid insulation layer, it may be added in the form of a plate of sheet metal, preferably solid, or plywood bonded to it. insulation to form the rigid insulation layer.

Advantageously and according to the invention, the spacers are fixed along lines orthogonal to a line of greater slope of the insulating layer in a staggered arrangement. The spacers are preferentially made in the form of parallelepipeds rectangles bent perforated sheet, having optionally a main face partly open. The spacers are placed evenly spaced, in parallel lines, orthogonal to the line of greatest slope of the wall on which the rigid insulation layer is fixed. In general, for vertical walls or roof panels, the spacers are aligned horizontally. On each line, the spacers are offset by half a step from the spacers of the adjacent lines. They are fixed by their longest side face on the anti-sinking coating of the rigid insulation layer by any appropriate means, for example by gluing, screwing, riveting or any combination of these means.

Advantageously and according to the invention, the spacers of the same line are interconnected by U-shaped beams to cap said spacers. According to an advantageous characteristic, the facing plate is fixed on the U-shaped beams. In order to keep the facing plate away from the rigid insulation layer and to reinforce the resistance of the insulation device according to the invention, the spacers are made integral with each other by U-shaped beams, preferably made of folded perforated sheet and having two wings separated by a core of an inner width adapted to allow the two wings of the U to cap each spacer. The minimum length of the beams is adapted so that each beam can at least partially cover a spacer at each end of the beam. The mounting of the beams is preferably without overlapping so that the outer face of the core of each beam is in a common plane for each wall. It is thus possible to put the perforated facing plates on the beams and fix them in a simple manner, for example by means of blind rivets passing through the perforations of the facing plate and the beam.

Advantageously and according to the invention, the facing plate is adapted to receive roofing accessories adapted to be fixed on said facing plate. The rigid and perforated facing plates make it possible to fix directly on the roof panels and / or on the walls devices such as Photovoltaic or fluid circulation solar panels and to guide their cables or connecting lines. Similarly, fluid circulation coils can be simply hung on the perforated facing plates, for example by means of collars, so as to constitute a heating network to accelerate the melting of a layer of snow deposited on the siding. Other accessories, for example networks of light spots can thus be arranged on the vertical walls to form display elements and / or lighting.

• on fixe sur ladite paroi une première face, dite face de contact, d'une couche d'isolant rigide et imperméable,
• on fixe des entretoises sur une deuxième face, dite face externe, de la couche d'isolant rigide opposée à la face de contact, avec un pas prédéterminé selon des lignes parallèles et orthogonales à une ligne de plus grande pente de la paroi, les entretoises étant décalées d'un demi pas entre deux lignes adjacentes,
• on relie entre elles les entretoises d'une même ligne par des poutrelles en forme de U, de telle sorte que lesdites poutrelles viennent coiffer les entretoises, et
• on fixe sur lesdites poutrelles une plaque de parement rigide et perforée de manière à ménager une lame d'air entre ladite plaque de parement et la face externe de la couche d'isolant rigide.

The invention also relates to a method of thermal insulation of a wall implementing the device. According to this method:

• fixed on said wall a first face, said contact face, of a rigid and impermeable insulating layer,
• spacers are fixed on a second face, said external face, of the rigid insulating layer opposite to the contact face, with a predetermined pitch along lines parallel and orthogonal to a line of greater slope of the wall, the spacers being offset by half a step between two adjacent lines,
• interconnecting the spacers of the same line by U-shaped beams, so that said beams are capped the spacers, and
• fixed on said beams a rigid and perforated facing plate so as to provide a blade of air between said facing plate and the outer face of the rigid insulation layer.

Advantageously and according to the invention, before fixing the facing plate, is fixed between each line of spacers, on the outer face of the rigid insulation layer, bags of granular insulation.

Advantageously and according to the invention, each bag is arranged in such a way that its largest dimension is parallel to the lines of spacers.

The invention also relates to a method and a thermal insulation device characterized in combination by all or some of the characteristics mentioned above or below.

• la figure 1 est une vue en coupe du dispositif d'isolation selon l'invention ;
• la figure 2 est une vue en perspective montrant le placement des entretoises et des poutrelles d'un dispositif d'isolation selon l'invention ;
• la figure 3 est une vue en perspective montrant le placement des sacs d'isolant granulaire selon l'invention ;
• la figure 4 est une vue en coupe en perspective d'un sac d'isolant granulaire selon l'une des variantes de l'invention.

Other objects, features and advantages of the invention will become apparent from the following description and the appended drawings in which:

• the figure 1 is a sectional view of the isolation device according to the invention;
• the figure 2 is a perspective view showing the placement of the spacers and beams of an isolation device according to the invention;
• the figure 3 is a perspective view showing the placement of granular insulating bags according to the invention;
• the figure 4 is a perspective sectional view of a granular insulating bag according to one of the variants of the invention.

The thermal insulation device 2 shown in FIG. figure 1 is intended to isolate a wall 1 of a building, (wall, sloped roof or terrace, etc.) by an applied fixture on the face of this wall facing the outside of the building. The device 2 comprises a layer 3 of rigid and impermeable insulation fixed on the wall 1 by a contact face 31. The layer 3 of rigid and impermeable insulation is for example constituted, in its thickness, at least one stratum 33 of insulating material such as expanded polystyrene or expanded polyurethane. These materials are generally in the form of closed cell foam making them impermeable to water. They also have good intrinsic rigidity, even if they are sometimes fragile. Depending on the desired thermal resistance and / or, as described below, the nature of the wall 1, the thickness of the insulating material is variable and may be formed of several layers of insulating material bonded together.

The rigid insulation layer 3 also has an anti-sinking coating 34 in the form of a plywood plate or sheet metal, preferably solid. This coating 34 is generally bonded in the factory on one side of the thickness of the insulating material to allow it to have additional resistance to bending and to prevent the insulating material from being damaged during site manipulation. Otherwise, the coating 34 can be glued to layers of insulation material on site. It can be used for this a prepainted steel sheet with a thickness of 0.75 to 1 mm or a sheet of plywood 8 to 12 mm thick. The layer 3 of rigid insulation may consist of a plurality of rectangular plates juxtaposed to cover the surface of the wall 1. These plates may comprise on their edge assembly means such as a bouvetage.

Depending on the wall to be insulated, three main cases can be envisaged: the thermal insulation device 2 is fixed on a vertical wall such as an outer wall, or on a sloping wall such as a roof pan. In the latter case, it is possible to use the isolation device according to the invention directly on the frame or on a roof already made when it is sheet metal, for example formed of steel tanks.

In the case of attachment to a vertical wall, the layer 3 of rigid insulation is preferably adhered to the wall by adhesive beads, for example expansive foam if necessary assisted by anchors. Other attachment methods known to those skilled in the art for external insulation may also be employed as long as they allow sufficient insulation to be held on the wall. When the insulation device according to the invention is placed on the roof, it is necessary to remove the cover if it does not allow laying flat (tiles, corrugated sheet, etc.). In this case, it is preferable to place a vapor barrier directly on the existing framework and for example to maintain it by nailed battens. The layer 3 of insulation is then glued on the battens. In some cases, it is possible to keep the existing roof, for example when it consists of flat sheets having at regular intervals stiffeners trapezoidal section (steel tanks). In this case, it is possible to bond between the stiffeners a first layer of insulating material, a thickness substantially equal to the height thereof to form a flat surface. The laying of the layer 3 of rigid insulation is then completed by bonding on this layer of a second layer of insulating material comprising the coating 34 anti-punching.

Once the layer 3 of rigid insulation fixed to the wall 1 is fixed on its outer face 32 (which is also the outer face of the coating 34 anti-punching) spacers 4 of generally parallelepiped shape (rectangular parallelepiped). These spacers 4 are made for example of lacquered perforated sheet and formed by folding and riveting. These spacers 4 are fixed for example by gluing and / or riveting and / or screwing on the anti-punching coating 34, interposing a reinforcing plate 13 if necessary ( figure2 ).

The spacers 4 are fixed on their face corresponding to the thickness and the length of the parallelepiped, regularly spaced along a pitch P, aligned along the length of the spacer along lines orthogonal to the slope of the wall 1 Thus, for straight walls or regular roof sections, the spacers 4 are aligned in horizontal lines themselves regularly spaced from each other.

For example, the spacers 4 are 250 mm long, 150 mm wide and 70 mm thick. They are arranged in a 600 mm pitch on a horizontal line and offset by half a step on the adjacent lines. The spacing between strut lines is also of the order of 600 mm without this being a necessity, these dimensions being able to vary according to the calculations of resistance and the regulation Snow and Wind applicable to the building.

The spacers 4 are made integral along the lines of spacers by beams 5 having a core 5a and two wings 5b folded orthogonally to the core to form a U-shaped profile. The width of the core 5a of each beam is adapted so that it can come to cap the face of the spacers opposite to the attachment face thereof and that the flanges 5b of the beam extend towards the fixing face flanking the spacer. The length of the beams 5 is preferably equal to an integer number of pitch P, generally two or three, with a tolerance by a lower value so as to avoid any overlap of a beam on the adjacent beam. The length of the beams must also be sufficient so that each end covers the spacer which it caps on at least 50 mm. The beams are fixed on the spacers by blind rivets placed through the flanges of the beams and the main faces of the spacers they cover so as not to create roughness on the surface of the webs of the beams so as to fix a plate 6 of rigid facing and perforated at a predetermined distance from the layer 3 of rigid insulation corresponding to the width of the spacers 4.

The facing plate 6 is preferably made by means of lacquered perforated sheet metal plates placed in abutment on the beams 5 and fixed on them by means of blind rivets. Preferably, there is a rivet on each spacer and a rivet on the web of the beam between each pair of spacer. The facing plate 6 is rigid enough to withstand forces exerted by a possible layer of snow (mainly on the roof) or by the wind (particularly on the walls). The facing plate 6 is also perforated so as to allow the passage of air through the perforations to prevent heating such as can be encountered on solid sheets.

In addition, the use of a rigid perforated facing plate 6 allows the precipitation water to flow at least partly through the plate and also allows the perforations to be used to simply attach accessories 17 to this plate. . Examples of accessories that can be easily fixed include solar panels, photovoltaic or hot water (solar water heater) and their cables or connecting pipes. In cold climates where the plates 6 are likely to be covered with snow, it is possible to attach snow guards to prevent falling snow flakes around the roofs or coils circulating a heat transfer fluid to accelerate snow removal. Other accessories can also be easily put in place, such as for example light strings or light emitting diodes forming an advertising display screen.

According to an advantageous characteristic of the thermal insulation device according to the invention, a layer 8 of granular insulating material 9 is interposed between the outer face 32 of the layer 3 of rigid insulation and the facing plate 6. Preferably, the thickness of this layer 8 of granular insulation is limited to two thirds of the gap between the outer face 32 of the rigid insulation and the facing plate 6 to leave a free space to maintain an air gap 7 under the plate 6 facing.

The granular insulator 9 may preferably be composed of expanded clay beads, porous or not, or pumice granules or pozzolan granules. In order to maintain this granular insulator in place, it is placed in preferably parallelepipedic bags 10 made of synthetic nonwoven fabric, for example made of polypropylene geotextile needle felt. Such a textile has the advantage of being naturally porous and can be assembled by thermo welding.

Such a bag 10 is illustrated in perspective cut by a median plane to the figure 4 and has two rectangular main faces 14a and 14b placed facing one another and whose respective edges are heat sealed together to form a closed bag. The main face 14a is further perforated so as to allow direct entry of the precipitation water. Between the main faces 14a and 14b, rectangular partition walls 11 are placed parallel to each other and welded to the two main faces by a flap 15 formed on their long edge to define cells 16. The width of the partition walls 11 is provided to maintain substantially constant the thickness of the layer 8 of granular insulator 9. The filling of the cells 16 of the bag 10 is effected by one of the orthogonal edges to the partition walls and the edge is closed by thermo welding of edges facing the main faces.

The dimensions of the bags 10 are provided to be multiples of the pitch P for the length so as to lay them parallel to the lines of spacers 4 resting on at least two spacers and to correspond to the spacing between two lines of spacers for the width. The bags 10 are fixed on the outer face of the layer 3 of rigid insulation by adhesive beads 12, parallel to the lines of spacers. The bags 10 are arranged in such a way that the direction of the partition walls 11, which also defines the largest dimension of the cells 16, is parallel to the spacer lines 4 (and therefore perpendicular to the line of greatest slope of the wall on which the isolation device is placed) so that the length of the cells 16 is also orthogonal to this line of greatest slope (see Figure 3 ).

For example, the dimensions of a bag 10 adapted to the thermal insulation device whose dimensions have been given further are of the order of 600, 1200 or 1800 mm long, 600 mm wide and the constant thickness maintained by the partition walls 11 is of the order of 100 mm.

Alternatively, the bags 10 may be made in a single cell formed of a cylindrical envelope obtained by folding on itself a sheet of geotextile felt and welding of its edges so as to form a cylinder with a length of one , two or three steps P and a diameter substantially equal to the distance between the outer face 32 of the layer 3 of rigid insulation and the facing plate 6. In order to protect the air space 7 beneath it, the cylindrical bag is only filled to 80% of its capacity, allowing it to be crushed on at least two strips of adhesive 12 to obtain an oblong section of which the small diameter corresponds to the desired thickness of the layer 8 of granular insulation. In this variant embodiment, the cylindrical bags are arranged in such a way that the axis of the cylinder (which corresponds to the largest dimension of the single cell) is parallel to the lines of spacers 4, several bags being used to fill the gap between two lines of spacers. Of course, the bags 10 may be arranged in parallel or staggered rows, each bag resting on two other bags.

Due to the presence of this layer of granular insulation, the thermal inertia of the insulation device and therefore of the insulated building with this thermal insulation device is improved. In addition, the precipitation waters reaching the facing plate 6 through at least in part through its perforations and reaches the layer 8 of granular insulation in which it is temporarily trapped. Precipitation runoff is thus slowed down, minimizing the risk of clogging rainwater evacuation. In addition, in the event of rapid alternation of precipitation and sunshine, the evaporation of the trapped water creates a local air conditioning phenomenon.

Of course, this description is given by way of illustrative example only and the person skilled in the art will be able to make numerous modifications without departing from the scope of the invention, such as for example modifying the dimensions and the arrangement of the spacers and the bags of granular insulation to fit the geometry of the building to be insulated. Similarly, the accessories that can be attached to the facing plate 6 are not limited to the devices described above, the perforations of the facing plate may also allow to fix a thatch roofing for example.

Claims (15)

- Device (2) for thermal insulation from the outside of a wall (1) of a building, particularly applicable to walls and roofs, characterized in that it comprises: a layer (3) of rigid and impervious insulation comprising a first face, said contact face (31) adapted to be fixed on said wall, and a second face, said external face (32), opposite to the face of contact, a plate (6) of rigid and perforated facing, and spacers (4) fixed on said outer face and adapted to maintain said facing plate away from the outer face and to provide an air gap (7) between said facing plate (6) and the outer face (32). ) of the layer (3) of rigid insulation. - Insulating device according to claim 1, characterized in that it further comprises a layer (8) of a granular insulator (9) between the layer (3) of rigid insulation and the plate (6) facing . - Insulating device according to claim 2, characterized in that the granular insulator (9) is a porous granular insulator. - Insulating device according to one of claims 2 or 3, characterized in that the granular insulator (9) is contained in at least one bag (10) of nonwoven synthetic fabric, particularly needle punched geotextile. - Insulating device according to claim 4, characterized in that each bag (10) has a substantially cylindrical shape, a diameter less than or equal to the distance between the outer face (32) of the layer (3) of rigid insulation and the facing plate (6). - Insulating device according to claim 4, characterized in that each bag (10) has a substantially parallelepipedal shape and comprises partitions, said partition walls (11), rectangular, parallel and regularly spaced whose long edges are fixed to main faces (14a, 14b) of each bag to maintain a distance between said main faces less than or equal to the distance between the outer face (32) of the rigid insulation layer (3) and the facing plate (6). - Insulating device according to one of claims 5 or 6, characterized in that at least one (14a) of the main faces (14a, 14b) of each bag (10) is perforated. - Insulation device according to any one of claims 1 to 7, characterized in that the layer (3) of rigid insulation has on its outer face (32) a coating (34) anti-depression on which are fixed spacers (4). - Insulating device according to any one of claims 1 to 8, characterized in that the spacers (4) are fixed on the layer (3) of rigid insulation with a predetermined pitch (P) along parallel lines, the spacers being offset by half a step between two adjacent lines. - Insulating device according to claim 9, characterized in that the spacers (4) of the same line are interconnected by beams (5) U-shaped to cap said spacers. -Isolation device according to claim 10, characterized in that the plate (6) facing is fixed on the beams (5) U-shaped. - Insulation device according to any one of claims 1 to 11, characterized in that the plate (6) facing is adapted to receive accessories (17) cover adapted to be fixed on said facing plate. - Method of thermal insulation of a wall (1) of building from the outside, according to which: a first face, referred to as the contact face (31), is fixed on said wall (1) with a layer (3) of rigid and impermeable insulation, spacers (4) are fixed on a second face, referred to as the outer face (32), of the layer (3) of rigid insulation opposite to the contact face, with a predetermined pitch (P) along parallel and orthogonal lines. to a larger line slope of the wall, the spacers being offset by half a step between two adjacent lines, the spacers (4) of the same line are connected together by U-shaped beams (5), so that said beams come to cover the spacers, and a rigid and perforated facing plate (6) is fixed on said beams (5) so as to provide an air gap (7) between said facing plate (6) and the outer face (32) of the layer ( 3) rigid insulation. - Insulating method according to claim 13, characterized in that , before fixing the plate (6) facing, is fixed between each line of spacers (4) on the outer face (32) of the layer (3). ) of rigid insulation, bags (10) of granular insulation (9). - Insulating method according to claim 14, characterized in that each bag (10) is arranged such that the largest dimension of the cell or cells which form it is parallel to the lines of spacers.

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