DE102013011078B4 - Process for the local rehabilitation of mold problem areas on the inside of an outer shell of buildings as well as the use of a filling material that is largely impermeable to water vapor and has high-grade thermal insulation properties - Google Patents

Abstract

A method for the local rehabilitation of mold problem areas (10) in the area of geometric thermal bridges on the inside of an outer shell of a building, in which a material (46) is applied in the mold problem areas (10) which contains an insulating material with low thermal conductivity and a hardening binder characterized in that, prior to the application of the material (46), the substrate is removed from the inside of the outer shell and that a depression (44) that occurs when the substrate is removed is filled with the material (46) which has a coefficient of thermal conductivity of less than 10 W / m K and thus has high thermal insulation properties and forms a vapor barrier that is largely impermeable to water vapor, so that the amount of water that can be sorbed from the inside by the filling material is less than the amount of water that can be released to the outside through desorption.

Description

The present invention relates to a method for the local rehabilitation of mold problem areas in the area of geometric thermal bridges on the inside of an outer shell of a building, in particular of old buildings, in which a material is applied in the mold problem areas that contains an insulating material with low thermal conductivity and a hardening binding agent Replacement for removed subsoil. The invention also relates to the use of a filling material that is largely impermeable to water vapor, so that the amount of water that can be sorbed from the inside by the filling material is less than the amount of water that can be released to the outside through desorption, with heat-insulating properties in the form of a Filler compound or a foam as a replacement for worn subsoil on the inside of the outer shell of buildings in the area of geometric thermal bridges.

It is not uncommon for mold problems to occur in apartments in old buildings, which are often caused by geometric thermal bridges in the outer shell of a building housing the old apartment. At low ambient temperatures, the temperature of the building's outer shell also drops. If the rooms adjoining the inside of the outer shell are heated, this has the result that the temperature of the inner wall surfaces of the outer walls is lower than room temperature and the air flowing past them cools. The greatest cooling occurs here in areas of geometric thermal bridges. Since the amount of moisture that can be absorbed by the air is temperature-dependent, the relative humidity increases when it cools down. Correspondingly, the relative humidity and thus the equilibrium moisture content of the capillary pores (sorption) present in the building materials of the outer shell increase in the vicinity of the above-mentioned inner wall surfaces, which favors the formation of condensation. Since mold can settle and grow if the sorption equilibrium moisture content exceeds a value that corresponds to a relative humidity of more than approx. 80%, mold problems can easily arise in the area of the geometric thermal bridges.

The geometric thermal bridges that lead to mold problems are found in old buildings primarily in areas where the outer surface of the building envelope around which cold air flows is larger than the inner surface around which warm air flows, e.g. where two external walls or two external walls and a ceiling of the building collide. Since more heat can flow out into the environment here than in neighboring areas (cooling rib effect), the transmission heat losses are higher, which is why the room-side surface temperatures drop more sharply.

To eliminate mold problems or the causes of mold problems, it is already known to apply a layer of insulation to the entire outside of the outer shell of the building or to its inside inside the building or, if double-walled masonry is present, to make core insulation with polystyrene granules or the like, so that at low outside temperatures, the inside or room-side component surface temperatures are reduced less. Existing thermal bridges that allow mold colonization are not taken into account or not taken into account separately, so that, given the often small extent of the mold problem areas, these measures are relatively complex and therefore expensive and often also uneconomical. Since the insulation layer on thermal bridges has the same layer thickness as on the rest of the wall surface, it can also not always be ensured that in the area of the geometric thermal bridges the thermal transmittance in the mold problem areas is reduced sufficiently to reliably prevent renewed mold infestation.

When an additional layer of insulation material is applied to the inside of the outer shell of the building, the outward flow of heat can be reduced, which leads to an increase in the surface temperature on the inside. At the same time, however, as a result of the lower heat flow into the outer shell, its temperature drops so that it is lower than before with the same ambient and internal temperature behind the insulation material layer. This allows water vapor, which diffuses through the insulation layer to the outside, to condense behind the insulation layer, whereby new mold can form over a large area there.

It is also known to locally heat mold problem areas or the geometric thermal bridges leading to mold formation. However, this energetic treatment makes it necessary to lay power lines up to the corresponding areas, which causes a not inconsiderable effort, results in follow-up costs due to the energy requirement and usually does not comply with the VDE safety guidelines.

In addition, so-called insulation wedges are available on the market, ie flat wedges made of a foamed insulation material, in particular made of extruded polystyrene, which can be glued to the inside of the outer shell of the building in areas with problems with mold. As the insulation wedges cannot be embedded in the subsurface, they protrude into the interior space after they have been installed and are visible even when the wallpaper is over, which affects the aesthetic appearance after the renovation. In addition, the insulation wedges can only be adapted to the actual requirements to a limited extent, as they are only manufactured pre-assembled in certain dimensions, so that the renovation cannot be limited to the mold problem areas and parts of the problem areas have to remain unrefurbished.

Based on this, the invention is based on the object of providing a method of the type mentioned at the outset that makes it possible, with simple means, to ensure sustainable and permanent renovation in the mold problem areas caused by geometric thermal bridges without the renovation work also including surrounding areas where no renovation is required.

According to the invention, this object is achieved on the one hand by a method according to the features of claim 1 and also by a use according to the features of claim 9.

In the context of the present patent application, the term “highly insulating properties” means that the cured filler material has the lowest possible thermal conductivity of less than 0.10 W / m · K, preferably less than 0.08 W / m · K, and best of about 0.06 W / m · K.

The term "largely impermeable to water vapor" means in the context of the present patent application that the water vapor diffusion resistance number µ according to DIN 4108-3 of the cured filler material is so high that the resulting water vapor diffusion equivalent air layer thickness of the filler material, which is also referred to as the sd value and the The diffusion openness or impermeability of the filler material indicates that it is clearly above the sd value of the building materials (mortar, stone, etc.) that follow the outside of the outer shell, so that the amount of water that can be sorbed from the inside by the filler material is lower than the amount of water that can be released to the outside through desorption.

The invention is based on the idea that, from an economic point of view, it makes sense to limit the renovation to the bare minimum, i.e. only to the mold problem areas, in other words the areas in which a mold lawn has already formed or in which there is considerable danger there is a formation of mold.

In these areas, the method according to the invention can increase the surface temperature on the inside of the outer shell of the building due to the insulating properties of the filler material and prevent diffusion of water vapor into and through the filler material due to the vapor barrier formed by the filler material. By increasing the surface temperature on the inside of the outer shell, the relative humidity there decreases and thus the risk of mold formation. Since the filling material also acts as a vapor barrier, the penetration of moisture from the room air into the filling material and condensation of moisture behind the filling material are prevented, thus reliably counteracting the formation of new mold at this point. In areas with geometric thermal bridges, this enables easy and sustainable control of mold colonization and growth. In contrast to the known methods, the renovated areas can also be provided with any wall decor, including vinyl wallpaper susceptible to mold, after which the renovated areas can no longer be visually differentiated from neighboring areas.

Especially for old buildings, in which the economy, especially on the landlord side, plays a role, the method according to the invention represents a simple, inexpensive and innovative solution for the permanent restoration and maintenance of living comfort, which can be implemented even by technically average laypeople without special knowledge of building physics.

Except in areas that are damp from the outside and in which there is therefore a lack of sealing, the invention basically allows a limited local renovation. As experience shows that if there are mold problems in the area of geometric thermal bridges, such as outer corners or edges of interiors, window connections and the like, a lack of sealing as the exclusive or additional cause of mold colonization can be ruled out with a very high probability, expert examinations prior to the renovation are also not mandatory required.

1. 1) Die maximale Wasserdampfaufnahme von Luft hängt von der Temperatur ab. Unter Normalbedingungen, wie normalem Luftdruck beträgt die maximale Wasserdampfaufnahme je m³ Luft etwa 17,3 g/m³ bei einer Temperatur von 20 °C, etwa 9,4 g/m³ bei einer Temperatur von 10 °C und nur etwa 4,8 g/m³ bei einer Temperatur von 0 °C. Da das Sorptionsverhalten von Baustoffen bei Abkühlung proportional zur relativen Luftfeuchtigkeit zunimmt, erhöht sich die von Baustoffen über Sorption aufzunehmende Wassermenge proportional zur relativen Feuchtemenge.
2. 2) Bei niedrigen Umgebungstemperaturen, z.B. im Winter, ist die Temperatur der innen- oder raumseitigen Oberflächen einer Außenhülle eines Gebäudes durch den Wärmestrom grundsätzlich niedriger als die Raumlufttemperatur. Im Bereich geometrischer Wärmebrücken, wie zum Beispiel an den Gebäudeaußenkanten oder Gebäudeecken, ist jedoch die Abkühlung infolge von höheren Transmissionswärmeverlusten durch die Gebäudehülle besonders stark. Daher muss vor allem dort für eine geringere Abkühlung gesorgt werden, damit, bezogen auf ein übliches Wohnraumklima von 20 °C und 50 % relativer Luftfeuchtigkeit in beheizten Innenräumen, die Oberflächentemperatur an den Innenseiten der Außenhülle zur Schimmelvermeidung mehr als 12,6 °C und einschließlich einer Sicherheit mehr als 14 °C beträgt.
3. 3) Schimmelwachstum ist bei einer relativen Luftfeuchtigkeit von etwa 80 bis 98 % möglich. Da sich infolge der Abkühlung von Luft deren relative Luftfeuchtigkeit erhöht, kommt es bei schlecht gedämmten Wohngebäuden (Altbauten) vornehmlich im Bereich von geometrischen Wärmebrücken zur Schimmelbildung an der Innenseite der Außenhülle des Gebäudes.
4. 4) Diese Schimmelbildung kann durch eine Verbesserung der Wärmedämmeigenschaften der Außenhülle des Gebäudes im Bereich der geometrischen Wärmebrücken verhindert werden, indem dort die Transmissionswärmeverluste bzw. der Wärmeabfluss nach außen reduziert wird. Dadurch kühlt im Bereich der geometrischen Wärmebrücken die innen- oder raumseitige Oberfläche weniger stark ab, was zu einem Anstieg der Temperatur an der Innenseite der Außenhülle führt. Die Bereiche, deren Oberflächen weniger stark abkühlen, liegen genau dort, wo sich Schimmelpilze ansiedeln, wie z.B. in einer äußeren Raumecke eines Innenraums der Bereich, in dem zwei Außenwände und eine Decke des Innenraums zusammenstoßen.
5. 5) Einer Schimmelneubildung innerhalb der Außenhülle des Gebäudes hinter den sanierten Bereichen wird entgegengewirkt, indem eine Sorption von Wasserdampf aus der Raumluft und dessen Diffusion in die Außenhülle verhindert werden.

The invention is based on the following theoretical considerations:

1. 1) The maximum water vapor absorption by air depends on the temperature. Under normal conditions, such as normal air pressure, the maximum water vapor absorption per m ^{3 of} air is about 17.3 g / m ³ at a temperature of 20 ° C, about 9.4 g / m ³ at a temperature of 10 ° C and only about 4, 8 g / m ³ at a temperature of 0 ° C. Since the sorption behavior of building materials is proportional to the relative If humidity increases, the amount of water to be absorbed by building materials via sorption increases proportionally to the relative amount of humidity.
2. 2) At low ambient temperatures, e.g. in winter, the temperature of the inside or room-side surfaces of an outer shell of a building is generally lower than the room air temperature due to the heat flow. In the area of geometric thermal bridges, for example on the outer edges of the building or building corners, the cooling is particularly strong as a result of higher transmission heat losses through the building envelope. Therefore, especially there, a lower cooling must be ensured, so that, based on a normal living room climate of 20 ° C and 50% relative humidity in heated interiors, the surface temperature on the inside of the outer shell is more than 12.6 ° C and inclusive to prevent mold safety is more than 14 ° C.
3. 3) Mold growth is possible at a relative humidity of around 80 to 98%. Since the relative humidity of the air increases as the air cools down, mold formation on the inside of the outer shell of the building occurs primarily in the area of geometric thermal bridges in poorly insulated residential buildings (old buildings).
4. 4) This mold formation can be prevented by improving the thermal insulation properties of the outer shell of the building in the area of the geometric thermal bridges by reducing the transmission heat losses or the heat flow to the outside there. As a result, the interior or room-side surface cools less in the area of the geometric thermal bridges, which leads to an increase in the temperature on the inside of the outer shell. The areas, the surfaces of which cool down less strongly, are exactly where molds settle, such as the area in an outer corner of an interior where two outer walls and a ceiling of the interior collide.
5. 5) The formation of new mold within the outer shell of the building behind the renovated areas is counteracted by preventing the sorption of water vapor from the room air and its diffusion into the outer shell.

A preferred embodiment of the invention provides that the filling material is a pasty filler with which the recess is filled. Such a leveling compound can be used in a similar way to known leveling compounds to repair holes or bumps.

Alternatively, however, it is also possible to use a filler material in the form of a hardening foam with a high vapor density, with which the recess is foamed, preferably after it has been covered with a “casing” towards the interior. The foam can be, for example, a polyurethane-based foam.

In order to ensure that the filler material has the best possible thermal insulation properties, its bulk density should preferably be as low as possible, since the heat permeability is generally proportional to the bulk density. A filler material with a bulk density of less than 1 g / cm ³ and preferably of less than 0.8 g / cm ³ and most preferably of 0.5 g / cm ³ or less is therefore expediently used.

In order to obtain such a low bulk density, the insulating material is expediently composed of hollow microspheres, the density of which is between 0.125 and 0.6 g / cm ³ , or of particles of crushed extruded rigid polystyrene foam, the density of which is between 0.02 and 0.06 g / cm ³ and which, like hollow microspheres, have a closed-cell structure and therefore very low permeability for water or water vapor. If necessary, foam glass can also be used as insulation material, which is less easy to process, but which is almost vapor-tight and has a very low insulation value.

On the other hand, the grain size distribution of the insulation particles in the filler material is chosen so that the gaps are as small as possible and thus the proportion of binder used to close the gaps between the insulation particles can be kept as low as possible.

In order to make the filler material as impermeable to steam as possible, both an insulating material with high water vapor diffusion resistance, such as hollow microspheres and / or crushed extruded polystyrene, and a binding agent with high water vapor diffusion resistance are advantageously used. In addition, the capillary pore volume of the binding agent can be reduced to zero or almost zero by embedding the insulating material particles in a closed matrix of binding agent that completely fills the gaps between the insulating material particles. Another alternative is to coat the cured filler material introduced into the recess with a covering layer impermeable to steam, for example by gluing on a thin aluminum foil or by applying a coating impermeable to water vapor.

According to a further preferred embodiment of the invention, the binding agent is a hardening synthetic resin, since synthetic resins are well suited for gluing the insulation particles together and, after hardening, ensure sufficient cohesion of the filler material even if the volume fraction of the binder compared to the volume fraction of the insulation material in the filler material is relatively low and is, for example, below 20% by volume, preferably below 10% by volume. The synthetic resin is preferably a chemically or reactively curing material, such as a two-component mixture, which cures through reaction of the two components, so that no air access into the interior of the filler material is required for curing or that there are no cavities form by volatilizing constituents and the filling material can thus be made more easily impermeable to steam.

Geometric thermal bridges, where mold problems can occur, are usually found where the interior, from which heat is supplied from the outer shell, has a smaller surface than the outside of the outer shell, where the heat is dissipated to the outside air, such as For example, on building outer corners and edges, where two outer walls or two outer walls and a ceiling of the inner space meet in an interior. In these areas, the subsurface is expediently removed on both sides by an inner edge between the two outer walls and on both sides by an inner edge between each of the outer walls and the ceiling, the depth and width of the recess formed during the removal, preferably gradually increasing towards the corner of the room. In addition, the depth of the recess formed during the ablation in the corner of the room, which depends on the heat flow and the thermal conductivity of the filler material, is advantageous, where it should be at least 20 mm and preferably about 40 mm and decrease evenly to zero towards the edges of the recess .

In order to prevent mold problems from occurring later in the vicinity of the rehabilitated mold problem areas, it can be advantageous to remove the subsurface a little way beyond the visible mold problem areas, for example by removing one in an upper corner of the room when refurbishing a problem area that is already infected with mold Inside the interior, the subsurface is removed along the three inner edges that meet in the corner of the room, preferably with an addition of 50 to 100 mm opposite the limit of the mold infestation, the edges of the depression formed by the removal preferably approximate hyperbolically to the inner edges in relation to the corner of the room.

In order to make the recess filled with the filling material invisible to the naked eye, the surface facing the interior space is preferably ground off after the filling material has hardened, if necessary to achieve flatness, until it is flat with the surrounding wall surfaces. The renovated parts of the inside of the outer shell of the building are then papered and / or painted for decoration, the wallpaper and / or the paint should extend over the edges of the recess filled with filler material. There are no restrictions whatsoever with regard to the material to be used for decoration, so that, for example, vinyl wallpapers or other organic coverings that generally favor mold can also be used.

• 1 zeigt eine perspektivische Ansicht eines unsanierten Schimmelproblembereichs mit Schimmelbefall in einer Raumecke eines Gebäudes zwischen zwei Außenwänden und einer Decke eines Innenraums;
• 2 zeigt eine vergrößerte Schnittansicht entlang der Linie II-II der 1;
• 3 zeigt eine Ansicht entsprechend 1, jedoch nach dem Abtragen von Untergrund im Schimmelproblembereich;
• 4 zeigt eine Schnittansicht entlang der Linie IV-IV der 2;
• 5 zeigt eine Schnittansicht entlang der Linie V-V der 2;
• 6 zeigt eine Schnittansicht entlang der Linie VI-VI der 2;
• 7 zeigt eine Ansicht entsprechend 2, jedoch nach dem Auffüllen der beim Abtragen des Untergrundes entstandenen Vertiefung mit einer Spachtelmasse und nach dem Glätten der Oberfläche der ausgehärteten Spachtelmasse;
• 8 zeigt eine Schnittansicht entlang der Linie VIII-VIII der 7;
• 9 zeigt eine Schnittansicht entlang der Linie IX-IX der 7;
• 10 zeigt eine Schnittansicht entlang der Linie X-X der 7;
• 11 zeigt eine Ansicht entsprechend 8, jedoch nach Abschluss der lokalen Sanierung des Schimmelproblembereichs;
• 12 zeigt eine Schnittansicht entlang der Linie XII-XII der 11.

The invention is described in more detail below with reference to an exemplary embodiment shown in the drawing.

• 1 shows a perspective view of an unrefurbished mold problem area with mold infestation in a corner of a building between two outer walls and a ceiling of an interior;
• 2 FIG. 11 shows an enlarged sectional view along the line II-II of FIG 1 ;
• 3 shows a view accordingly 1 , but after removing the substrate in the mold problem area;
• 4th FIG. 4 shows a sectional view along the line IV-IV of FIG 2 ;
• 5 FIG. 11 shows a sectional view along the line VV of FIG 2 ;
• 6th FIG. 6 shows a sectional view along the line VI-VI of FIG 2 ;
• 7th shows a view accordingly 2 , but after filling the indentation created when removing the substrate with a filler and after smoothing the surface of the hardened filler;
• 8th FIG. 8 shows a sectional view along the line VIII-VIII in FIG 7th ;
• 9 FIG. 9 shows a sectional view along the line IX-IX of FIG 7th ;
• 10 FIG. 11 shows a sectional view along the line XX of FIG 7th ;
• 11 shows a view accordingly 8th , but after completion of the local remediation of the mold problem area;
• 12 FIG. 11 shows a sectional view along the line XII-XII of FIG 11 .

The mold problem area shown in the drawing 10 is located in an upper corner of the room 12 an interior 14th an old building with two outer walls 16 , 18th and a blanket 20th of a building housing the old apartment. From the corner of the room 12 a vertical inner edge extends out 22nd between the two outer walls 16 , 18th downward. Between the ceiling 20th and the two outer walls 16 , 18th horizontal inner edges extend 24 , 26th in to each other and to the inside edge 22nd perpendicular directions from the corner of the room 12 path. As best in 2 shown, exist the outer walls 16 , 18th for example from a brickwork 28 off with mortar 30th grouted bricks 32 and one on the inside of the bricks 32 applied plaster layer 34 .

As a result of a cooling rib effect, ie a stronger cooling of the outer shell of the building in the area of the room corner 12 , takes the temperature of the masonry at low ambient temperatures 28 stronger than in neighboring areas. This has the consequence that it is adjacent to the corner of the room 12 , which forms the geometric thermal bridge, also the temperature of an inner surface 36 the plaster layer 34 on the two outer walls 16 , 18th and the ceiling 20th is lower than in neighboring areas. This in turn cools the room air around the corner of the room 12 around, which leads to an increase in the relative humidity and, under unfavorable conditions, to the dew point being undershot. This has the consequence that it is on the corner of the room 12 adjacent area of the inner surface 36 the plaster layer 34 Condensate can also form in the plaster layer 34 penetrates. Since molds can already settle at a relative humidity of around 80%, if there is enough food, such as cellulose from a layer of plaster, it can 34 covering wallpaper 38 , in the area of the corner of the room 12 quickly to the formation of a mold lawn 40 come. The mold lawn 40 will be on the wallpaper 38 visible in the form of larger and smaller often black mold spots, as in 1 shown, although the mycelium of the mold often extends into the plaster layer 34 extends into it. The mold problem can therefore usually be caused by a new wallpaper 38 or a superficial mold treatment cannot be permanently removed.

As in 1 shown, the visible mold lawn extends 40 in such a case mostly starting from the corner of the room 12 on both sides along the vertical inner edge 22nd between the outer walls 16 . 18th down and on both sides along the two horizontal inner edges 24 , 26th between the ceiling 20th and the two outer walls 16 , 18th to the right and left respectively up to an area in which the temperature of the inner surface 36 and thus the air temperature of the room air is higher, so that the relative humidity of the room air is below 80%.

Along all three inside edges 22nd , 24 , 26th shows the mold lawn 40 usually right on the corner of the room 12 its greatest width on that of the corner of the room 12 away along the inner edges 22nd , 24 , 26th gradually decreasing to zero as in 1 shown.

In order to make it possible to renovate the mold problem area shown in the drawing with little effort and without special knowledge of building physics, the adjacent area of the mold lawn is first used 40 as well as on the inside of the two outer walls 16 , 18th and the ceiling 20th with a pry tool, i.e. the wallpaper 38 , the plaster layer 34 and partly also the masonry 28 worn away as in the 3 to 6th shown.

When removing the substrate 38 , 34 and 28 will be in the two outer walls 16 , 18th and in the ceiling 20th a recess in the neighborhood corner 44 formed along the inner edges 22nd , 24 , 26th depending on requirements, i.e. depending on the existing insulating properties of the masonry 28 and the plaster layer 34 and the extent of the mold colonization about 500 to 800 mm from the corner of the room 12 extends away.

As best in the 3 and 4th shown, has the recess 44 in the immediate vicinity of the corner of the room 12 has a maximum width B and a maximum depth T, the former about 200 to 300 mm and the latter about 25 to 40 mm. Along the three inner edges 22nd , 24 , 26th takes both the depth T and the width B of the recess 44 from the corner of the room 12 away gradually down to zero, the edges of the indentation 44 have a generally hyperbolic course and are asymptotically attached to the inner edges 22nd , 24 , 26th approach. The depth T of the depression also increases 44 from the corner of the room 12 out to the edges 54 the depression gradually decreases.

After removing the subsurface 38 , 34 and 28 becomes the recess formed 44 completely with a pasty filler 46 filled as in the 7th to 10 shown. The filler 46 contains small particles of insulation material with low thermal conductivity and a hardening synthetic resin binder. The insulation material and the binding agent are selected so that the filler 46 after hardening of the binder, on the one hand, has heat-insulating properties and on the other hand it is almost completely impermeable to water vapor, so that it acts as a vapor barrier.

The insulating material can be, for example, hollow microspheres made of glass with a bulk density of 0.125 to 0.6 g / cm ³ (without pile and capillary pores), which are available from 3M or Omega Minerals Germany GmbH and the filler 46 can be added as a filler. For example, at 3M under the designation K1 Hollow microspheres made of soda-lime borosilicate glass with a density of 0.125 g / cm ³ and a grain size distribution of 10% with a grain size <30 µm, 50% with a grain size <65 µm, 90% with a grain size <110 µm and a have a maximum diameter of 120 µm.

Preferably, however, an insulating material is used which consists predominantly of crushed, extruded rigid polystyrene foam with a density between 0.02 and 0.06 g / cm ³ and preferably of crushed processing residues from panels or blocks made of extruded rigid polystyrene foam. Particles made from crushed, extruded rigid polystyrene foam have, like hollow microspheres, a closed-cell structure and therefore have little or no permeability for water or water vapor. However, since these particles have a higher pore size, hollow microspheres are advantageously added to them in order to fill the gap volume between the polystyrene particles and thus the amount of binder required in the filler 46 to reduce or to increase the filling level.

Instead of particles made of crushed, extruded rigid polystyrene foam, balls made of expanded polystyrene can also be used as insulation material, which would make processing considerably easier, reduce the need for binding agents and improve the thermal insulation value of the filler.

The binder is a two-component synthetic resin made of a resin and a hardener, which are mixed and added to the particulate insulation material in a paste-like, flowable form so that the synthetic resin can be evenly distributed over the surfaces of the insulation material particles. An example of a suitable two-component synthetic resin is a sandwich adhesive from the company Büfa, which is available under the number 740-0072 and was developed in particular for the production of sandwich panels for boat hulls made of fiberglass-reinforced synthetic resin. After curing, this synthetic resin is almost completely vapor-tight and does not absorb any moisture.

If only microspheres are used as insulation, the three components of the filler are used 46 , that is, microspheres, resin and hardener are pre-dosed and distributed in a self-mixing disposable dosage packaging, which is preferably designed in the form of a syringe or cartridge from which the filler is made 46 directly into the recess 44 can be pressed or injected. If, in addition, particles of crushed, extruded rigid polystyrene foam are used, these are expediently mixed in shortly before processing the mixture of resin and hardener, without pre-assembly taking place.

The mixing ratio of insulation and binding agent in the filler 46 is chosen in both cases so that the filler 46 on the one hand has a pasty consistency in the processing state, is easy to process and in the recess 44 that the filler adheres to the substrate 46 however, on the other hand, it contains as much insulation material as possible and as little binding agent as possible. The mixing ratio is preferably set so that the bulk density of the filler 46 is as low as possible in the processing state and is therefore significantly smaller than the density of the substrate. A bulk density is preferred that is considerably less than 1 g / cm ^{3 in} order to ensure a high insulation value or good thermal insulation capacity.

Since the thermal insulation capacity of thermal insulation materials usually increases with the decreasing density of the thermal insulation materials, the cured filler due to the low density 46 the transmission heat loss in the vicinity of the corner of the room 12 through the filler 46 reduced, so that the geometric thermal bridge previously existing there is eliminated. In other words, thanks to the insulating properties of the filler 46 the heat flow in the corner of the room 12 reduced so that the surface temperature on the inside of the putty 46 filled recess 44 compared to the adjacent inner surface of the outer walls 16 , 18th and the ceiling 20th is higher. As the hardened putty 46 Due to the closed-cell structure of the insulation particles and the air impermeability of the binder, it forms a vapor barrier that is largely impermeable to moisture, and no moisture from the room air can get into the hardened filler 46 and penetrate through this into the underlying masonry, which is due to the internal thermal insulation through the filler 46 will cool down even more than before after the renovation. As the masonry 28 behind the filler 46 is thus kept dry, a new formation of mold is prevented there.

After the filler has hardened 46 is already when filling the recess 44 smooth inner surface facing the interior 50 the filler 46 , if necessary, sanded down until they match the adjacent inner surface 36 the plaster layer 34 or the wallpaper 38 on the two outer walls 16 , 18th and the ceiling 20th is flat.

Then the two outer walls 16 , 18th and the ceiling 20th with a new wallpaper 52 wallpapered over and / or painted, as in 13 shown, whereupon the rehabilitated area according to 12 is no longer visible.

Claims (9)

A method for local restoration of mold problem areas (10) of geometric in the area of thermal bridges to the inside of an outer envelope of a building, in which a material (46) is applied in the mold problem areas (10) containing an insulating material of low thermal conductivity and a thermosetting binder, characterized characterized in that, prior to the application of the material (46), the substrate is removed from the inside of the outer shell and that a depression (44) that occurs when the substrate is removed is filled with the material (46) which has a coefficient of thermal conductivity of less than 10 W / m K and thus has high thermal insulation properties and forms a vapor barrier that is largely impermeable to water vapor, so that the amount of water that can be sorbed from the inside by the filling material is less than the amount of water that can be released to the outside through desorption. Procedure according to Claim 1 , characterized in that the filling material (46) is a filler with which the recess (44) is filled. Procedure according to Claim 1 , characterized in that the filling material (46) is a hardening foam with which the recess is foamed. Method according to one of the Claims 1 to 3 , characterized in that the insulating material comprises extruded polystyrene and / or hollow microspheres. Method according to one of the Claims 1 to 4th , characterized in that the binder is a synthetic resin. Method according to one of the Claims 1 to 5 , characterized in that in mold problem areas (10) in the vicinity of a room corner (12) of an interior of the building, at which two outer walls (16, 18) and a ceiling (20) of the interior collide, the substrate on both sides of an inner edge (22 ) between the two outer walls (16, 18) and on both sides of an inner edge (24, 26) between each of the outer walls (16, 18) and the ceiling (20), the depth (T) and the width (B) the removal towards the corner of the room (12) gradually increases. Procedure according to Claim 6 , characterized in that the depth (T) of the removal is greatest in the corner (12) of the room and gradually decreases towards the edges of the depression (44). Method according to one of the preceding claims, characterized in that the substrate is removed beyond the mold problem areas (10) and the resulting depression (44) is filled with the filler material (46). Use of a filler material that is largely impermeable to water vapor, so that the amount of water that can be sorbed from the inside by the filler material is less than the amount of water that can be released to the outside through desorption, the filler material being an insulating material with low thermal conductivity and a hardening material Contains binding agent and has a thermal conductivity of less than 0.10 W / mK for the local rehabilitation of mold problem areas (10) on the inside of an outer shell of a building, the filling material in the form of a filler or foam as a replacement for previously removed The underground on the inside of the outer shell is used in the area of geometric thermal bridges and forms a vapor barrier there.

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