EP2522785B1 - Method and system for insulating the interior of external building walls - Google Patents

Description

The invention relates to a method and a system for internal insulation of external building walls.

State of the art

On the thermal insulation of buildings ever higher demands are made. In general, the usually plate-shaped thermal insulation materials used for this purpose are externally attached to the building, as this leads to solutions that are less prone to damage than interior insulation systems from a construction-physical point of view. Because the taking place through a building exterior wall water vapor diffusion to compensate for a regularly existing vapor pressure gradient between inside and outside can lead to condensation water discharge especially in an internally running thermal insulation. The condensate usually precipitates from the inside to the outside with a water vapor diffusion behind the thermal barrier coating, since the water vapor - at corresponding outdoor temperatures - meets here on a much cooler layer. If the precipitated condensation water can not be discharged to the outside via the exterior wall of the building, the moisture penetrates back into the thermal insulation layer. A moist thermal barrier coating, however, has a significantly lower thermal insulation capability than a dry one, so that sufficient thermal insulation is no longer guaranteed. In addition, prolonged moisture penetration can lead to mold growth.

However, systems for internal insulation of external building walls are indispensable, especially if the formation of an external insulation is not possible and / or is not desirable, as is the case for example with listed facades.

To avoid the above-mentioned problems, two prior art systems are primarily known from the prior art.

The first known system for internal insulation of a building exterior wall provides for the use of a vapor barrier. The vapor barrier is mounted directly or indirectly on the interior side of the thermal barrier coating, so that a diffusion of water vapor is prevented from the inside to the outside. The use of a vapor barrier is not without problems. In particular, with the use of a vapor barrier increases the cost of producing the building exterior wall, since the vapor barrier layer must be performed without interruption. In particular, the individual vapor barrier webs have to be adhesively bonded to one another in the region of the joints and in the region of their connections to adjacent components in order to form the vapor barrier layer. Furthermore, care must be taken that no subsequent damage to the vapor barrier layer takes place. Damage can for example already be caused by the impact of a nail, so that a permanent functioning of the vapor barrier can not be guaranteed. Because a vapor pressure equalization takes place even by the smallest gaps or holes, so that water vapor enters the structure of the building exterior wall.

The second known system provides for the use of a capillary-active vapor-permeable thermal insulation board. Capillary-active thermal insulation panels have the property of being able to easily absorb moisture via the capillary and to be able to dissipate it again. Accordingly, capillary-active thermal insulation panels allow rapid dehydration of the system in the event of condensed water failure, thus avoiding long-lasting moisture penetration and the associated risk of mold formation. However, it decreases by a regularly increased Water absorption the thermal insulation capacity of the thermal insulation material. This can only be compensated by the fact that the thermal insulation material is applied in a greater layer thickness. In the case of interior insulation, however, this is associated with a loss of space.

In addition, from the DE 42 10 392 A1 a component, in particular a thermal insulation board, which is impregnated or coated with an impregnating or coating agent in such a way that it has a certain water vapor transmission resistance which is greater than that of the base material of the thermal insulation panel. The impregnation or coating should make a vapor barrier unnecessary.

From the DE 197 06 223 A1 In addition, a capillary-active wall renovation plate for the desalination of salt-laden walls emerges. The capillary activity of the plate causes moisture and salts dissolved therein to be absorbed from the wall. To attach the plate to uneven walls, an adhesive such. As a cement adhesive can be used. This must be permeable to water to allow desalination of the wall. The wall renovation panel additionally improves the thermal insulation of the wall due to its high porosity.

Based on the above-mentioned prior art, the present invention seeks to provide a process-safe and little damage-prone method and system for internal insulation of a building exterior wall. In particular, the method according to the invention or the system according to the invention should make it possible to omit a vapor barrier.

To solve the problem, a method for internal insulation of a building exterior wall with the features of claim 1 and a system for internal insulation with the features of claim 7 are proposed. advantageous Embodiments of the invention are specified in the respective subclaims.

Disclosure of the invention

In the method according to the invention for internal insulation of a building exterior wall, at least one capillary-active, water vapor-permeable thermal insulation panel is used to form a thermal insulation layer, which is fastened by means of an adhesive to the inside of the building exterior wall. The adhesive used in this case is used at the same time to form a moisture-regulating intermediate layer, which is able to absorb moisture, especially precipitated condensate, temporarily store and release again.

Due to the formation of a moisture-regulating intermediate layer, which according to the invention coincides with the adhesive layer for fixing the thermal insulation panel on the inside of the building exterior wall, can on the arrangement of a vapor barrier - however a capillary active diffusion-open thermal insulation board is used - omitted. The capillary-active, vapor-permeable thermal insulation board prevents rapid drying of the system in the event of a condensation water failure. Nevertheless, no worse thermal insulation performance of the thermal insulation panel can be determined in a condensation water. This is due to the fact that the moisture is almost completely absorbed by the moisture-regulating intermediate layer and temporarily stored. Surprisingly, it was found that the moisture temporarily stored in the intermediate layer neither leads to mold formation nor to a loss of stability of the wall structure. If the dew period is over, ie there is a vapor pressure gradient favoring vapor diffusion from outside to inside, the moisture temporarily stored in the moisture-regulating intermediate layer is removed as water vapor back into the interior of the room.

The advantages of a method according to the invention are obvious. On the one hand, the formation or arrangement of a vapor barrier is dispensable, so that the processing reliability increases. On the other hand, a longer lasting moisture penetration of the thermal insulation and a concomitant reduced thermal insulation of the thermal insulation are avoided. It is therefore not necessary to form the thermal barrier coating at the expense of the interior in a greater strength. Furthermore, the system applied by means of a method according to the invention permits vapor diffusion, by means of which moisture can be withdrawn from the interior during the dew period and moisture can be supplied during the evaporation period. The inventive method therefore leads to a breathable interior insulation of a building exterior wall whose moisture-regulating properties ensure a healthy and pleasant indoor climate inside the building.

According to a preferred embodiment of the invention, the adhesive for full-surface bonding of the thermal insulation board with the building exterior wall and the formation of a continuous moisture-regulating intermediate layer is evenly distributed on the surface to be bonded of the building exterior wall and / or the thermal insulation board. Any voids between the building exterior wall and the thermal insulation panel are preferably completely filled by the adhesive to ensure that the moisture is retained in the moisture control interlayer. It is also within the meaning of the invention that such cavities are leveled with a ground plaster, which then forms the basis for the moisture-regulating adhesive of the invention.

Further preferably, the adhesive is applied by spraying, brushing, rolling and / or filling, preferably with the aid of a tooth trowel, on the inside of the building exterior wall and / or the thermal insulation board. These procedures allow a uniform order. Particularly preferred the processing in the so-called floating-buttering process, in which the adhesive is applied both to the wall surface and to the thermal insulation board. To form the required layer thicknesses of the moisture-regulating intermediate layer, it may be advantageous to apply the adhesive in several operations on the wall surface, wherein between the operations of the adhesive, the possibility of drying should be given.

Advantageously, the storage capacity of the moisture-regulating intermediate layer is adjusted such that the absorption capacity of moisture is ensured over the period of a dew period. The duration of a dew period depends on the individual case. The determinants of the individual case are the season, the time of day, the geographical position of the building, the orientation of the outer wall of the building in relation to the direction of the compass and the specific use of the interior bounded by the outer wall of the building, to name but a few. All factors have an influence on the temperature and the moisture content of the boundary layers or air layers adjacent to the outer wall of the building and on the other side. For example, the dew period may last only one night or a full winter.

The ability of the adhesive to absorb moisture and temporarily store it is preferably adjusted via its layer thickness. Further preferably, the layer thickness is 0.2 mm to 20 mm, preferably 0.5 mm to 10 mm. In addition, an adhesive composition can be used which results in the formation of an adhesive layer having improved sorption properties.

According to one embodiment of the invention it is provided that at least one hydrophobic properties having thermal insulation board is used to form the thermal barrier coating. Preferably, the thermal insulation board has a water vapor diffusion resistance coefficient μ <20, further preferably μ <10. Due to the hydrophobic properties is a water absorption of the Thermal insulation panel largely excluded, while the thermal insulation panel is also open to diffusion with appropriate water vapor resistance resistance number. If the properties of the thermal insulation panel according to the invention are met, the individual embodiment can vary widely. It is irrelevant whether the thermal insulation board consists of a homogeneous insulating material or a combination of different insulating materials. Likewise, for example, a coating applied to a surface of the insulating board and / or an applied reinforcing or nonwoven fabric has no influence on the invention, as long as the openness of diffusion is ensured.

In a preferred embodiment of the system according to the invention for internal insulation of external building walls thermal insulation panels are used with a high thermal insulation effect. On the one hand, this leads to an advantageously lower layer thickness of the system structure and thus to a small loss of living space. On the other hand, at low Dämmschichtstärken the water vapor diffusion resistance is low, which is advantageous in terms of the diffusion-open nature of the invention the heat insulation plate. Thermal insulation panels with such properties are based, for example, on hydrophobized silica airgel. Thermal insulation panels with thermal conductivities λ <0.030 W / (m * K), in particular λ <0.025 W / (m * K) and preferably λ <0.020 W / (m * K), are therefore preferably used.

Furthermore, it is proposed that a coating, for example in the form of a filler, a single or multi-layer plaster, which may be reinforced by the introduction of a reinforcing fabric, a paint or the like, at least one bonded to the building exterior wall to form a thermal barrier coating thermal insulation board, is applied as a room-side conclusion. As a result, a visually attractive final coating can be formed.

The system for internal insulation of a building exterior wall proposed for solving the problem initially set comprises at least one capillary-active, vapor-diffusion-open thermal insulation board for forming a thermal insulation layer and an adhesive for fixing the thermal insulation board to the inside of the building exterior wall, wherein the adhesive also forms a moisture-regulating intermediate layer, which in the It is able to absorb moisture, especially precipitated condensate, to temporarily store and release it. The system of thermal insulation board and adhesive has the advantages already described above in connection with the method according to the invention, so that reference is made to avoid repetition thereof.

The thermal insulation panel preferably has hydrophobic properties. This ensures that no or at least only a very low water absorption takes place. Further preferably, the thermal insulation board has a water vapor diffusion resistance coefficient μ <20, preferably μ <10, so that a water vapor diffusion is ensured by the thermal insulation board.

To form the moisture-regulating intermediate layer, a mineral or organic adhesive may be used. The adhesive preferably has a water vapor diffusion resistance coefficient μ <25.

Furthermore, an unclaimed use of an adhesive for fastening a thermal insulation panel on the inside of a building exterior wall and for forming a moisture-regulating intermediate layer between the thermal insulation panel and the building exterior wall is described.

The glue thus assumes a double function. On the one hand, he keeps the thermal insulation board on the inside of the building exterior wall, on the other hand he holds precipitating condensation in the intermediate layer stored until the dew period of a Evaporation period is replaced and the moisture in the form of water vapor can be discharged through the thermal insulation panel back into the room.

Hereinafter, an inventive method or system for internal insulation of a building exterior wall will be described with reference to an embodiment.

embodiment

The internal insulation system according to the invention is applied to a load-bearing wall former, for example a 20 cm thick C35 / 45 concrete wall. The heat transfer coefficient of the building exterior wall made of concrete is 3.44 W / (m ² * K). For thermal insulation, a 3 cm thick thermal barrier coating comprising at least one heat-insulating panel based on hydrophobized silica airgel is applied to the inside of the building exterior wall. The thermal insulation board has a thermal conductivity λ = 0.019 W / (m * K) and a water vapor diffusion resistance factor μ = 10. Due to the excellent thermal insulation properties of the thermal insulation board, the thermal barrier coating can be made relatively thin. At the same time, a water vapor diffusion is made possible by the selected thermal insulation panel. The attachment of the thermal insulation board to the building exterior wall by means of a mineral adhesive, which according to DIN EN 998-1 as a diffusion-open coating must have a water vapor diffusion resistance coefficient μ <25. The adhesive layer formed for fastening the thermal insulation panel, which at the same time serves according to the invention as a moisture-regulating intermediate layer, has a layer thickness of 1 cm.

On the thermal insulation board a reinforcing layer is applied with an inserted reinforcing fabric. The reinforcing layer consists of a 4mm thick layer of a mineral plaster, which also according to DIN EN 998-1 as a vapor-permeable coating a water vapor diffusion resistance coefficient μ <25 must have. As a final coating, a silicate finishing coat of grain size K 1.5 according to DIN EN 15824 is applied to the reinforcing layer.

• Fig. 1 einen Querschnitt durch eine Gebäudeaußenwand mit einem aus dem Stand der Technik bekannten Innendämmsystem umfassend eine Dampfsperre,
• Fig. 2 einen Querschnitt durch eine Gebäudeaußenwand mit einem weiteren aus dem Stand der Technik bekannten Innendämmsystem umfassend eine kapillaraktive diffusionsoffene Wärmedämmplatte und
• Fig. 3 einen Querschnitt durch eine Gebäudeaußenwand mit einem erfindungsgemäßen Innendämmsystem umfassend eine kapillarinaktive diffusionsoffene Wärmedämmplatte.

The inventive method or system for internal insulation of a building exterior wall is further explained with reference to the accompanying figures. These show:

• Fig. 1 a cross-section through a building exterior wall with a known from the prior art Innendämmsystem comprising a vapor barrier,
• Fig. 2 a cross section through a building exterior wall with another known from the prior art Innendämmsystem comprising a capillary active diffusion-open thermal insulation board and
• Fig. 3 a cross section through a building exterior wall with a Innenendämmsystem invention comprising a capillary active diffusion-open thermal insulation board.

Detailed description of the drawings

The Fig. 1 and 2 in each case a cross-section through a building exterior wall 1 with an according to the state of the art running internal insulation can be seen. The building exterior wall 1 is made of masonry and is 24cm thick. On the inside, in each case a 10 cm thick thermal barrier coating 2 is formed, which comprises at least one thermal insulation panel 3. The figures show an example of the temperature profile 8 through the building exterior wall 1 at an interior temperature of 18.5 ° C and an outside temperature of - 9.5 ° C.

Since warmer air is able to absorb more moisture than cooler air, there is not only a temperature gradient from inside to outside, but also a gradient in relation to the moisture absorbed in the air in the form of water vapor. The vapor pressure gradient is the reason that water vapor diffuses through the building exterior wall 1.

In the known embodiment according to the Fig. 1 a water vapor diffusion 10 is prevented by the building exterior wall, since the interior side, a vapor barrier 11 is arranged. In the absence of water vapor diffusion, no condensation water precipitates, so that the structure of the outer wall of the building is protected against condensation. However, the vapor barrier 11 is very susceptible to damage and protection against condensation only guaranteed if the vapor barrier 11 remains permanently undamaged. If the film used as a vapor barrier 11, for example, by hammering a nail injured, water vapor can get into the structure of the building exterior wall 1 and precipitate as condensation. The building exterior wall 1 is moistened within its structure, because the location of the condensation water 9 is usually in the region of the boundary layer between the thermal insulation panel 3 and the building exterior wall 1 (see Fig. 2 ). However, a drying of the wall is prevented at the same time by the inside of the room applied vapor barrier 11.

From the Fig. 2 shows an alternative embodiment of a known from the prior art interior insulation, which seeks to avoid the disadvantages of a vapor barrier 11. This is achieved by completely dispensing with a vapor barrier 11. At the same time a thermal insulation board 3 is used to form a thermal barrier coating 2, which is permeable and capillary active. The thermal insulation board is therefore suitable to absorb both water vapor, as well as moisture and to give them back to the interior via the capillary. The disadvantage, however, proves that the thermal insulation board 3 usually has a high moisture content and thus poor Thermal insulation values. In order to compensate for this, the layer thickness of the thermal barrier coating 2 generally has to be increased. As a result, however, valuable residential or office space is lost.

The above-mentioned disadvantages of internal insulation of a building exterior wall 1 can be remedied by using the method according to the invention or the system according to the invention. This is exemplary in the Fig. 3 shown. The structure of the building exterior wall 1 differs from that of the preceding already in that a thermal insulation board 3 is used, which is only 3cm thick. This is due to the fact that in the present case a thermal insulation board 3 based on hydrophobized silica airgel with a thermal conductivity λ = 0.019 W / (m * K) is used. The plate thus has over conventional thermal insulation panels improved thermal insulation properties. At the same time, however, such a plate is kapillarinaktiv, that is permeable to water vapor, but not for water. In order to prevent a condensation water within the structure of the building exterior wall 1, the formation or arrangement of a vapor barrier 11 according to the embodiment of the Fig. 1 required. If, on the other hand, a vapor barrier 11 is dispensed with, the use of a capillary-active thermal insulation board 3 is required.

The present invention now goes new ways by proposing the use of a capillary active thermal insulation board 3 for internal insulation of a building exterior wall 1, but at the same time waives a vapor barrier 11. In the event of a possible thawing water failure, the condensate in the present case is taken up by a moisture-regulating intermediate layer 6 which is formed between the thermal insulation panel 3 and the external building wall 1. To form the moisture-regulating intermediate layer 6, an adhesive 4 is used, which is applied to the inside 5 of the building exterior wall 1 and / or on the surface 7 to be bonded to the thermal insulation board 3. The glue 4 not only absorbs the condensate, but also stores it until the end of the dew period and then releases it back into the interior during the evaporation period by means of an opposite water vapor diffusion 10 '. In this case, a part of the moisture may also evaporate on the building exterior wall 1.

The inventive method and the system according to the invention thus have the advantages that a highly heat-insulating capillary active thermal insulation board 3 small thickness can be used, which leads to a gain in space. Furthermore, it is possible to dispense with a damage-susceptible vapor barrier 11. This also increases the processing security. Finally, the adhesive 4 is used to form the moisture-regulating intermediate layer 6, which at the same time serves to secure the thermal insulation panel 3 to the inside 5 of the external building wall 1. In this respect, the inventive method or system requires no increased workload.

LIST OF REFERENCE NUMBERS

1

Building outer wall

2

thermal barrier

3

thermal insulation board

4

Glue

5

inside

6

moisture-regulating intermediate layer

7

surface to be bonded

8th

temperature curve

9

Place of condensation water failure

10

Water vapor diffusion

11

vapor barrier

Claims (9)

1. A method for the internal insulation of an external building wall (1), at least one water-vapour-permeable thermal insulation board (3) being fastened to the inner side (5) of the external building wall (1) by means of an adhesive (4) to form a thermal insulation layer (2), the adhesive (4) at the same time being used to form an intermediate layer (6) that is capable of absorbing moisture, in particular precipitated dew, and releasing it again,
   characterised in that the thermal insulation board (3) has no capillary action and the intermediate layer (6) regulates moisture as well as being capable of temporarily storing moisture, in particular precipitated dew.
2. The method according to Claim 1,
   characterised in that the adhesive (4) for adhesively bonding the thermal insulation board (3) to the external building wall (1) over the whole area thereof and for forming a continuous moisture-regulating intermediate layer (6) is applied in a uniformly distributed manner to the face (7) of the external building wall (1) and/or of the thermal insulation board (3) to be adhesively bonded.
3. The method according to Claim 1 or 2,
   characterised in that the adhesive (4) is applied by spraying, spreading, rolling and/or trowelling, preferably with the aid of a notched trowel.
4. The method according to one of the preceding claims,
   characterised in that the ability of the adhesive (4) to absorb and temporarily store moisture is set by means of the layer thickness thereof, the layer thickness preferably being 0.2 mm to 20 mm, further preferably 0.5 mm to 10 mm.
5. The method according to one of the preceding claims,
   characterised in that at least one thermal insulation board (3) having hydrophobic properties is used to form the thermal insulation layer (2), said thermal insulation board preferably having a water vapour diffusion resistance value µ < 20, further preferably µ < 10.
6. The method according to one of the preceding claims,
   characterised in that a coating, for example in the form of a filler, a single- or multi-layered plaster, a paint or the like, is applied as a room-side finish to the at least one thermal insulation board (3) that is adhesively bonded to the external building wall (1) to form a thermal insulation layer (2).
7. A system for the internal insulation of an external building wall (1), comprising at least one thermal insulation board (3) that is open to water vapour diffusion to form a thermal insulation layer (2) and an adhesive (4) for fastening the thermal insulation board (3) to the inner side (5) of the external building wall (1), the adhesive (4) at the same time forming an intermediate layer (6), which is capable of absorbing moisture, in particular precipitated dew, and releasing it again,
   characterised in that the thermal insulation board (3) has no capillary action and the intermediate layer (6) regulates moisture as well as being capable of temporarily storing moisture, in particular precipitated dew.
8. The system according to Claim 7,
   characterised in that the thermal insulation board (3) has hydrophobic properties and preferably has a water vapour diffusion resistance value µ < 20, further preferably µ < 10.
9. The system according to Claim 7 or 8,
   characterised in that the adhesive (4) is a mineral or organic adhesive, which preferably has a water vapour diffusion resistance value µ < 25.

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