EP4650543A1 - Arrangement for sealing a roof - Google Patents

Abstract

An arrangement (20, 20a) for sealing a roof, in particular a flat roof, with existing roofing material (21) is provided. The arrangement comprises: a roof (22, 30) with existing roofing material (21); a vapor barrier (2a, 2b) on the existing roofing material, comprising: a moisture-impermeable and/or vapor-barrier separating layer (4) made of aluminum, a fleece layer (12) bonded to the separating layer, and an adhesive coating (17) arranged on one side of the separating layer (4) facing away from the fleece layer (4); and an elastic coating (16) made of polyurea or a polyurea mixture, arranged on the vapor barrier (2a, 2b), preferably on the fleece layer (12) of the vapor barrier (2a, 2b). wherein the vapor barrier (2a, 2b) is bonded to the existing roof covering (21) of the roof by means of the adhesive coating (17). A method for applying such an arrangement is also disclosed.

Description

The invention relates to an arrangement and a method for sealing a roof, in particular a flat roof, with existing roof covering.

Damage to a roof's waterproofing can lead to moisture accumulation, necessitating roof renovation. Roof renovation typically involves completely removing the existing roofing material and replacing it with new materials. This includes removing old roofing membranes, insulation, and/or vapor barriers or retarders. New waterproofing and insulation are then installed. Therefore, roof renovation is a time-consuming process. Furthermore, it incurs high costs for disposing of the removed materials, resulting in significant resource waste.

It is therefore an object of the invention to provide an easy-to-assemble and/or cost-effective arrangement for sealing a roof and a method for sealing a roof.

This task is solved using the features of the independent claims. Advantageous embodiments are the subject of the dependent claims.

According to claim 1, an arrangement for sealing a roof, in particular a flat roof, with existing roofing material is provided. The arrangement comprises a roof with existing roofing material; a vapor barrier on the existing roofing material, comprising: a moisture-impermeable and/or vapor-barrier separating layer made of aluminum, a nonwoven layer bonded to the separating layer, and an adhesive coating arranged on a side of the separating layer facing away from the nonwoven layer; and an elastic coating made of polyurea or a polyurea mixture, arranged on the vapor barrier, preferably on the nonwoven layer of the vapor barrier. The vapor barrier is glued to the existing roof covering of the roof using the adhesive coating.

The term "existing roof covering" refers to all elements already present on a roof, particularly a flat roof. Preferably, the existing roof covering is arranged on a concrete slab or trapezoidal metal sheeting. For example, the existing roof covering may include roof tiles, vapor barriers or vapor retarders, roofing felt, wooden sheathing with joists (especially in the case of a cold roof), waterproofing membranes or top layers made of materials such as bitumen, butyl, or PVC, or insulation.

The vapor barrier of the assembly is bonded to the top layer of the existing roof covering, and preferably the elastic coating is applied to the fleece layer of the vapor barrier. Preferably, the top layer of the existing roof covering is a waterproofing membrane or top layer membrane. The elastic coating preferably forms the top layer of the waterproofing. A surface protection layer, such as a gravel ballast, can be applied to the elastic coating.

Moisture can accumulate in an existing roof covering due to damage to the waterproofing membranes and/or vapor barriers. When renovating a roof, especially a flat roof, the entire roof material (particularly above a concrete slab or trapezoidal metal roofing) is usually removed, including waterproofing membranes, vapor barriers or damp-proof courses, insulation, and/or wooden sheathing in the case of a cold roof. Therefore, roof renovation involves high disposal costs, resource waste, and is time-consuming.

By using the above method for roof renovation, the existing roof covering preferably does not need to be removed at all, or only partially. If present, loose parts of the roof covering are preferably removed first. Preferably, the roof or roof covering is cleaned before the vapor barrier is applied, for example with water, and particularly preferably with a steam cleaner or high-pressure washer.

The vapor barrier is or will be glued directly onto the existing roof covering, preferably onto the existing roof covering that has been cleaned as described above. Therefore, [the following applies]: Disposal costs are very low and significantly fewer resources are wasted.

Removing loose parts and/or cleaning the roof covering ensures optimal adhesion between the vapor barrier and the existing roof covering, thus guaranteeing optimal functionality of the vapor barrier and the elastic coating.

The above arrangement is preferably used for the renovation of roofs, and particularly preferably for flat roofs, trapezoidal roofs and/or roofs with cavities such as cold roofs.

In this embodiment, insulation is laid between the existing roof covering, preferably between an existing top layer, and the vapor barrier, and in particular the vapor barrier is glued to the newly applied insulation.

The polyurea in the elastic coating is preferably water-repellent. Therefore, the elastic coating provides reliable protection against moisture from above.

Another particular advantage of elastic coatings made of polyurea or a polyurea mixture is that they can be reapplied to the existing roof covering at any time without any drawbacks (even over an existing polyurea coating). This allows, for example, the coating work to be interrupted and resumed at a later date, or damaged areas to be repaired, provided they are accessible. No disadvantages arise from this. The coating may simply be slightly thicker in these areas than in the rest, but this is not considered a disadvantage.

The polyurea coating preferably forms a particularly good adhesion and intimate bond with the fleece layer of the vapor barrier and is therefore difficult to remove from it.

Polyurea is a biological substance that is preferably produced from inorganic substances, whereby the production does not involve urea. Polyureas are preferably polymers formed by the polyaddition of isocyanates and amines. Typically, polyurea is produced by the polyaddition of diamines and diisocyanates. The polymer has a repeating structure similar to urea, hence the name polyurea. Another term for polyurea is aminoplast. Polyurea is highly resistant to solvents and chemicals and is also scratch-resistant. This polymer preferably has a short crosslinking time, resulting in rapid curing, especially when applied to the vapor barrier. The elastic coating is preferably applied in liquid form, for example, by spraying.

Preferably, the elastic coating has an elongation capacity of at least 400%, 600%, 700%, 800%, or 900%. Elongation capacity indicates how far the coating can be stretched or extended without breaking or tearing. Therefore, the coating is highly resistant to external forces, ensuring long-lasting moisture protection for a roof.

Unlike the prior art, in this vapor barrier, the aluminum separation layer provides the moisture barrier/vapor barrier, thus eliminating the need for bitumen as a moisture barrier/vapor barrier. Thanks to the aluminum separation layer, the vapor barrier has an _Sd value > 1500 m. The vapor barrier seals a roof, particularly a flat roof, against rising damp from the building interior or from the existing roof covering. The elastic coating preferably acts as the top layer and seals the vapor barrier against moisture from above. This elastic coating protects the vapor barrier from external environmental influences such as rain or other impacts.

The use of aluminum (instead of aluminum-bitumen membranes), especially aluminum combined with bitumen, butyl, acrylate, or hot-melt adhesives, significantly reduces the weight per unit area of the vapor barrier, thus simplifying handling. Furthermore, unlike vapor barriers made of bitumen membranes, aluminum is considerably less sensitive to temperature and remains flexible even at temperatures as low as -5°C, meaning the vapor barrier can be easily installed even at low temperatures.

Vapor barrier:

Preferably, the adhesive coating is designed as a full-surface or substantially full-surface adhesive coating. The full-surface adhesive coating ensures that the vapor barrier bonds completely with the underlying existing roof covering, in particular an existing waterproofing membrane or top layer. Preferably, the adhesive coating has a basis weight between 20 g/ ^m² and 200 g/ ^m² , more preferably between 40 g/ ^m² and 90 g/ ^m² , and most preferably between 50 g/ ^m² and 80 g/ ^m² .

The adhesive coating can be made of a hot melt adhesive, an acrylate adhesive, or a bitumen- or butyl-based adhesive. Preferably, the adhesive coating has a thickness in the range of 0.1 mm - 2.0 mm, 0.1 mm - 0.6 mm, 0.5 mm - 1.0 mm, 0.9 mm - 1.4 mm, 1.3 mm - 2.0 mm, and particularly preferably 0.3 mm.

Acrylate adhesives have high resistance to aging and temperature changes and are insensitive to UV radiation and oxidation. For example, the adhesive strips have a basis weight of 40 to 80 g/ ^m² , preferably 45 to 70 g/ ^m² , and particularly preferably about 50 g/ ^m² . Hot melt adhesives are based on originally non-adhesive synthetic resins, which are liquefied at temperatures above, for example, 150 °C. This process, upon recooling, gives them good tackiness and high adhesive strength. For example, acrylate adhesives can be readily applied using wet bonding. Acrylate or hot melt adhesives can be processed at temperatures down to -5 or -10 °C.

The adhesive coating is particularly preferred if it is cold-applied and/or can be applied at temperatures as low as -10 °C, -8 °C, or -5 °C. This allows the individual strips of the vapor barrier to be easily bonded to each other and/or to the existing roof covering.

Preferably, the vapor barrier is formed from adjacent, sheet-shaped individual strips, particularly preferably from adjacent individual strips, each or predominantly having a width of at least 100 cm, 110 cm, 120 cm, 140 cm or 150 cm.

'Laid side by side' tracks preferably means 'side by side' vapor barrier tracks, which also includes the fact that the laid tracks partially overlap.

The vapor barrier can consist of two, three, four, five, or more individual sheets laid side by side. Preferably, the adjacent sheets of the vapor barrier overlap at their edges, particularly with an overlap of at least 30 mm, 40 mm, 50 mm, 70 mm, or 90 mm.

Due to its roll-like design, the vapor barrier can be easily transported and installed. For example, it can be supplied in rolls with widths between 0.1 m and 1.5 m. Preferred widths are: 30 cm, 40 cm, 50 cm, 75 cm, 100 cm, 120 cm, 140 cm, or 150 cm. The low density of the vapor barrier allows for significantly more linear meters (m) per roll without compromising handling during installation. For example, a PVC vapor barrier typically comes in rolls of 25 m. A multi-layer vapor barrier, as described above, can be supplied in rolls of 100 m, meaning the vapor barrier can be installed in longer lengths without splicing, thus requiring fewer connections between individual rolls. Fewer connections mean less assembly work and fewer potential weak points in the sealing layer of the vapor barrier.

Preferably, the vapor barrier is waterproof for a specified period. The vapor barrier can thus function as a temporary seal on the existing roof covering. A temporary seal means that the vapor barrier provides a barrier against moisture/water for the specified period. This allows, for example, the initial installation of only the vapor barrier on the existing roof covering. The elastic coating made of polyurea or a polyurea mixture then does not need to be applied or sprayed directly onto the vapor barrier after its installation. This allows the installation of the vapor barrier and the elastic coating made of polyurea or a polyurea mixture to be spread over several days. If it rains, for example, between the installation of the vapor barrier and the application of the elastic coating made of polyurea or a polyurea mixture, the roof remains waterproofed by the vapor barrier for the specified period.

Preferably, the vapor barrier has a first protective layer which is connected to and/or applied to the side of the separating layer facing away from the nonwoven layer, and/or has a second protective layer arranged between the separating layer and the nonwoven layer.

The first and/or second protective layer can be made of a plastic, in particular polyethylene terephthalate (PET) or a PET film, e.g., high-density polyethylene (HDPE). The density of HDPE is, for example, between 0.94 g/ ^cm³ and 0.97 g/ ^cm³ . Preferably, the first and/or second protective layer has a thickness of 7 µm to 50 µm, more preferably 9 µm to 30 µm, and most preferably 10 µm to 20 µm.

For example, a first and/or second protective layer made of PET has a thickness of 12 µm. The use of PET offers the further advantage of increasing the density of the vapor barrier against moisture/vapor. In particular, when using a PET protective layer with a higher density or a thicker/stronger protective layer, the density (thickness) of the aluminum separating layer can be reduced without decreasing the _Sd value of the vapor barrier.

As an alternative to the second protective layer made of PET or HDPE, the second protective layer can be made of low-density polyethylene (LDPE). The density of LDPE, for example, ranges between 0.915 g/ ^cm³ and 0.935 g/ ^cm³ .

The first and/or second protective layer can have a basis weight of preferably 10 g/ ^m² - 60 g/ ^m² , more preferably 15 g/ ^m² - 50 g/ ^m² , and more preferably 20 g/ ^m² - 40 g/ ^m² . A flame-retardant (FR) LDPE coating, e.g., with a basis density of 35 g/ ^m² , is particularly preferably used as the second protective layer.

The first protective layer and/or the second protective layer are preferably alkali-resistant, so that the two protective layers protect the non-alkali-resistant aluminium from damage.

Preferably, the nonwoven layer is made of polypropylene (PP), polyethylene (PE), polyester, polybutylene terephthalate (PET), polybutylene terephthalate (PBT), or polyamide (PA). Particularly preferably, the nonwoven layer is designed as a spunbond nonwoven, especially as a hydrophilized (water-permeable) PP spunbond nonwoven. Preferably, the nonwoven layer has a basis weight in the range of 10 g/ ^m² - 160 g/ ^m² , 20 g/ ^m² - 140 g/ ^m² , or 30 g/ ^m² - 120 g/ ^m² , particularly a value of 100 g/ ^m² or substantially 100 g/ ^m² .

When using the vapor barrier, the fleece layer faces upwards or outwards. This means that the aluminum separating layer, when installed on a roof, faces the existing roof covering and, in particular, any existing top layer. Because the aluminum does not face upwards, it reduces glare for the installer, thus simplifying the installation process.

Preferably, the separating layer has a thickness in the range of 4 µm to 50 µm, more preferably 5 µm to 30 µm, and particularly preferably 6 µm to 10 µm. For example, the separating layer has a thickness of about 7 µm.

To protect the adhesive coating, the adhesive can be completely covered with a removable protective cover. This cover can be made of paper, polyethylene (PE), polyethylene terephthalate (PET), or a combination of these materials. The protective cover can be removed to allow for the installation of the vapor barrier.

Preferably, the vapor barrier also has a fabric layer arranged between the nonwoven layer and the second protective layer.

The fabric layer or weave is preferably a cross-linked (e.g., right-angled or nearly right-angled) thread system of longitudinal threads (warp threads) and transverse threads (weft threads), in which the threads pass over and under the transverse threads in a specific rhythm (weave pattern). The weave of the fabric, or the interweaving of the threads, creates a strong and dense bond that ensures high tensile strength and tear propagation resistance of the vapor barrier. During installation, mechanical damage to the vapor barrier can therefore be prevented or minimized, thus ensuring a tight seal against water and water vapor even under stress during or after installation. Preferably, the fabric layer is made of a natural fiber, glass fiber, or synthetic fiber (e.g., polyester or polyethylene (PE), in particular HDPE).

The fabric layer can have a thread density in the longitudinal and/or transverse direction of between 3 and 15 threads/cm, preferably between 5 and 10 threads/cm, and particularly preferably between 3 and 7 threads/cm, and additionally or alternatively have a grid spacing in at least one (grid) direction of a maximum of 5 mm, preferably a maximum of 4 mm, and particularly preferably a maximum of 2 mm. The specifications for thread density and grid spacing refer to an average thread density and grid spacing, taking into account a manufacturing tolerance.

Preferably, the fabric layer has a basis weight of 20 g/ ^m² - 150 g/ ^m² , more preferably 40 g/ ^m² - 120 g/ ^m² , and particularly preferably 50 g/ ^m² - 90 g/ ^m² . For example, the fabric layer has a basis weight of approximately 60 g/ ^m² .

Preferably, the vapor barrier further comprises an adhesive layer arranged between the second protective layer and the nonwoven layer (especially if the second protective layer consists of PET), wherein the adhesive layer is preferably selected from the group of polyolefins, such as PE or PP.

Preferably, the individual layers of the vapor barrier, and in particular the separating layer and the nonwoven layer, the separating layer and the first protective layer, the second protective layer and the separating layer, the second protective layer and the nonwoven layer and/or the second protective layer and the woven layer and/or the woven layer and the nonwoven layer, are joined together by means of bonding, laminating, spraying, fusing, linking and/or melt pressing.

Due to the use of the materials described above, the vapor barrier is significantly less temperature-sensitive compared to bitumen or PVC and remains flexible even at temperatures as low as -20°C to -40°C, allowing for excellent workability even at low temperatures. For example, the vapor barrier can be folded down to -20°C, e.g., to create an L-shaped or Z-shaped barrier.

The following is an example of the horizontal installation of a sheet-like vapor barrier with an adhesive coating, as described above, for sealing flat roofs. The vapor barrier can be cut to size before installation or glued directly from the roll onto the substrate to be sealed. When installing the vapor barrier, the protective paper is slowly and evenly peeled downwards while the sheet is carefully adhered to the existing roof covering (e.g., an old waterproofing membrane or top layer).

Adjacent strips should be overlapped by at least 80 mm to create a tight vapor barrier, ensuring an airtight seal against moisture and vapor. The overlap area must be carefully rolled.

The vapor barrier described above can have a basis weight of 120–300 g/ ^m² , preferably 130–250 g/ ^m² , and particularly preferably 140–200 g/ ^m² . For example, a basis weight of approximately 162 g/ ^m² . This means that the vapor barrier is at least 5 times lighter per square meter compared to a PVC moisture barrier of the same thickness (e.g., 1.2 mm).

Elastic coating:

Preferably, the elastic coating is applied or sprayed onto the vapor barrier as a full-surface and/or self-contained coating.

The elastic coating preferably forms the top layer of the roof waterproofing. Due to its full-surface application, the elastic coating has no weak points. This ensures the longevity of the roof waterproofing. Specifically, the elastic coating is applied or sprayed onto the vapor barrier in liquid form. The coating preferably cures quickly, for example, in less than 30, 20, 10, or 7 seconds after application.

The elastic coating is preferably applied as a two-component system using two-component mixing systems. Preferably, the two components are mixed directly in the nozzle head of an application device. For example, the two separate components are conveyed via separate lines to a nozzle head on a roof, where the components are mixed and the elastic coating is formed by the curing of the mixture after application to the roof. The components of the elastic coating are preferably solvent-free. Preferably, the first component contains amines and the second component contains isocyanates, which form the elastic coating through polyaddition upon mixing.

A static or dynamic mixer can be used for mixing in the nozzle head. In a static mixer, the components are mixed solely by the flow motion (i.e., there are no moving elements). A dynamic mixer includes a rotating element for mixing the components. This rotating element can be driven by the flowing components during the application of the elastic coating or by a motor. For example, the rotating element can be designed as a screw.

Preferably, the elastic coating comprises 90 to 100 wt.%, 90 to 95 wt.%, or 95 to 100 wt.% polyurea, or the elastic coating comprises a polyurea mixture with a polyurea content of 1 to 95 wt.%, 30 to 97 wt.%, 50 to 95 wt.%, or 75 to 95 wt.%. The polyurea or polyurea mixture may contain components of polyurethane, polyphenol, polyolefin, polypropylene, polyethylene, polystyrene, polyester, polyethylene oxide, polyterephthalate, polyacrylic, polyamide, or polycarbonate, either as a single component or as a mixture of various such substances.

All of the aforementioned substances are suitable for mixing with polyurea to, for example, increase elasticity or achieve other special properties, such as rapid setting.

The elastic coating preferably consists of a polyurea mixture with polyurethane and polyurea.

Preferably, the elastic coating contains 0 to 5 wt%, 0.01 to 4.5 wt% or 1 to 10 wt% _CO2 -binding additives to prevent foaming during crosslinking, in particular calcium oxide.

Preferably, the polyurea mixture comprises flame-retardant substances, preferably in the form of inorganic salts or organometallic compounds. Particularly preferably, the polyurea mixture comprises substances selected from the group consisting of calcium carbonate, aluminum trihydrate, magnesium hydroxide, sodium and/or potassium hydroxide stannate.

Roofs with solar panels or photovoltaic systems present an increased fire risk. The fire-retardant materials in the elastic coating can therefore reduce the fire risk to the roof itself should a fire break out on solar panels or photovoltaic systems. This makes the installation particularly suitable for roofs with solar panels or photovoltaic systems.

Preferably, the A) polyurea together with the B) _CO2 -binding additives and/or the C) further components (polyurethane, polyphenol, polyolefin, polypropylene, polyethylene, polystyrene, polyester, polyethylene oxide, polyterephthalate, polyacrylic, polyamide or polycarbonate as a single component or as a mixture) and/or The D) flame-retardant substances together comprise 95–100 wt.%, 97–100 wt.%, or 100 wt.% of the elastic coating. For example, A) + B) or A) + C) or A) + D) or A) + B) + C) or A) + B) + D) or A) + C) + B) or A) + B) + C) + B) together comprise 95–100 wt.%, 97–100 wt.%, or 100 wt.% of the elastic coating.

Preferably, the elastic coating is weatherproof and, in particular, waterproof and/or UV-resistant. Preferably, the coating exhibits high abrasion resistance and/or is scratch-resistant. This ensures lasting protection against moisture from above. The elastic coating can have a thickness in the range of 1–8 mm, 1–4 mm, 2–5 mm, 3–6 mm, 4–8 mm, preferably 2.5 mm.

Preferably, the existing roof covering is at least partially perforated (especially before the vapor barrier is applied and the elastic coating is installed). Preferably, the top layer, the vapor barrier, and all intermediate layers, such as insulation, wood sheathing in a cold roof, or a separating layer between the wood sheathing and the top layer, are perforated. This allows moisture to rise from below the newly applied vapor barrier to a level below it.

Alternatively or additionally, the arrangement includes at least one venting element positioned such that an inlet of the venting element is located below the (newly applied) vapor barrier and an outlet of the venting element is located above the elastic coating, allowing moisture and/or vapor below the vapor barrier to escape upwards through the vapor barrier and the elastic coating via the venting element. This allows existing moisture in the existing roof covering to escape from the existing roof covering through the newly applied vapor barrier and the elastic coating by means of the venting element, thus ventilating and drying the existing roof covering.

Preferably, the inlet of the ventilation element is arranged within the insulation of the existing roof covering. Preferably, the longitudinal extent of the ventilation element is vertical or nearly vertical, and/or the ventilation element is arranged vertically or nearly vertically.

For example, the venting element can be designed as a pipe element, with at least one inlet and/or at least one outlet in a wall of the The pipe element is arranged in a pipe element. Preferably, the pipe element has a plurality of inlets in its wall and/or in a first end region of the pipe element below the newly applied vapor barrier. Preferably, the pipe element has a plurality of outlets in its wall and/or in a second end region of the pipe element above the elastic coating. The venting element can include a fan that is actively driven to generate an airflow between the inlet and outlet of the venting element. This allows moisture to be actively removed from the existing roof covering.

Furthermore, a method for sealing a roof with an existing roof covering is provided. The method comprises: bonding a vapor barrier, in particular a vapor barrier as described herein, to the existing roof covering, wherein the vapor barrier comprises: a moisture-impermeable and/or vapor-barrier separating layer made of aluminum, a fleece layer bonded to the separating layer, an adhesive coating arranged on a side of the separating layer facing away from the fleece layer, wherein the vapor barrier is bonded to the existing roof covering of the roof with the adhesive coating, and subsequent application of an elastic coating made of polyurea or a polyurea mixture, in particular an elastic coating as described herein, to the vapor barrier, preferably to the fleece layer of the vapor barrier.

New insulation can be installed on top of the existing roof covering, preferably on top of an existing top layer, before the vapor barrier is glued on (i.e., the vapor barrier is glued onto the new insulation in this case).

Preferably, the method further comprises: cleaning the existing roof covering, in particular an existing top layer membrane, before applying the vapor barrier, preferably with water, and particularly preferably with a steam jet or high-pressure cleaner, and/or immediate application, preferably after cleaning, of the at least one vapor barrier to the existing roof covering.

Cleaning the roof can also include removing loose parts of the existing roofing material. It is particularly preferred to first remove loose parts of the existing roofing material and then clean the existing roofing material, especially the top layer, for example with water.

Preferably, the method further comprises: perforating the existing roof covering before applying the vapor barrier, preferably after cleaning the roof covering, so that any moisture present in the roof covering can rise to the newly applied vapor barrier.

Moisture can accumulate in the existing roof covering due to damage to the waterproofing membranes and/or vapor barriers. Therefore, it is preferable to perforate the existing roof covering at regular intervals. For example, this involves piercing the existing roof covering from top to bottom with a tool.

Preferably, the existing roof covering comprises a top layer or waterproofing membrane and/or a vapor barrier or vapor retarder and/or insulation arranged between the top layer and the vapor barrier. In the case of a cold roof, a wooden sheathing is arranged on the vapor barrier, and on the wooden sheathing, a possible separation layer and the top layer are placed. The wooden sheathing is preferably designed such that a cavity is formed between the wooden sheathing and the underlying insulation. Particularly preferably, the wooden sheathing is laid on joists arranged on the vapor barrier, with the joists separating the wooden sheathing from the underlying insulation.

Preferably, the existing roof covering above a concrete slab or trapezoidal sheet metal is perforated. Particularly preferably, the top layer membrane, the vapor barrier or vapor retarder, and each of the intermediate layers, such as insulation and/or, in the case of a cold roof, wood sheathing and/or a separating layer, are penetrated during perforation.

This allows existing moisture in the existing roof covering to rise to the newly applied vapor barrier, thus preventing moisture from accumulating in the existing roof covering.

Preferably, the method further comprises: creating at least one recess in the existing roof covering, and installing at least one ventilation element in the at least one recess before bonding the vapor barrier and applying the elastic coating, wherein the ventilation element is installed in the recess such that an inlet of the ventilation element is located below the vapor barrier and an outlet of the ventilation element is located above the elastic The coating is arranged so that any moisture present below the vapor barrier can escape upwards through the vapor barrier and the elastic coating via the venting element. Preferably, the inlet of the venting element is located within insulation or within a cavity (in the case of a cold roof) of the existing roof covering.

Thus, existing moisture in the existing roof covering can escape from the existing roof covering through the newly applied vapor barrier and the elastic coating by means of the ventilation element, i.e. the existing roof covering can be ventilated or dried.

This prevents blistering on the newly applied vapor barrier caused by rising moisture that collects beneath it. Furthermore, it allows moisture in the existing roof covering, particularly existing insulation, to escape, thus improving or preventing a reduction in insulation value. It also helps prevent mold growth in the existing roof covering.

The ventilation element can be passively designed, for example as a pipe element with an inlet and outlet without an actively driven component. Alternatively, the ventilation element can be actively designed, for example with a fan that is actively driven, so that an airflow is created from the inlet (i.e., in the existing roof covering) to the outlet (i.e., above the newly applied elastic coating).

The venting element can have a multitude of inlets and/or outlets, with the inlets located below the newly applied vapor barrier and the outlets above the elastic coating. For example, the venting element can be designed as a pipe element, with at least some of the inlets and/or outlets located in a wall of the pipe element.

Preferably, several ventilation elements are mounted on the roof; for example, at least 2, 3, 4, or 5 ventilation elements are mounted per 100 ^m² . The ventilation elements are preferably mounted in an edge area of the roof, but they can also be mounted at any other location on the roof.

Preferably, after the ventilation elements have been installed, the vapor barrier is glued in place, with recesses being made in the vapor barrier or individual vapor barrier sheets for the ventilation elements. The individual ventilation elements are thus preferably enclosed by one or more vapor barrier sheets.

The elastic coating is then preferably applied or sprayed on, with the elastic coating surrounding each of the venting elements and forming a continuous coating surface.

The at least one venting element is preferably sealed in such a way that a vapor-tight connection is created between the vapor barrier and the venting element(s) protruding through the vapor barrier. This ensures that no rising vapor or moisture can pass between the vapor barrier and the venting element. In other words, rising vapor or moisture below the bonded vapor barrier can only rise upwards through the vapor barrier and the elastic coating via the inlet of the venting element.

Preferably, the elastic coating is applied in liquid form, preferably by spraying. Alternatively or additionally, the elastic coating can be processed down to -10 °C, -8 °C or -5 °C.

The elastic coating can be applied multiple times. This allows the application process to be interrupted and seamlessly resumed later. If damage occurs, the elastic coating can be reapplied without any negative consequences.

Preferably, the elastic coating is created or produced by applying a mixture of two starting components to the vapor barrier, wherein the starting components are preferably mixed directly in the nozzle head of an application device before the resulting mixture is applied to the vapor barrier, preferably to the nonwoven layer of the vapor barrier.

The elastic coating is therefore a two-component system, whereby the two components (amines and isocyanates) are only mixed together in the nozzle head. The mixing process initiates a curing process, which preferably lasts a maximum of 30 s, 20 s, or 10 s. For example, the two components can be stored in separate containers at the bottom of a building or on a vehicle and conveyed through separate lines to a nozzle head on a roof.

Preferably, the vapor barrier is formed from adjacent, sheet-shaped individual strips, wherein the method comprises: gluing two or more adjacent individual strips of vapor barrier, wherein adjacent strips of the vapor barrier are particularly preferably laid overlapping in their edge area, in particular with an overlap area of at least 30 mm, 40 mm, 50 mm, 70 mm or 90 mm.

Preferably, the vapor barrier is formed by individual sheets laid side by side, with the elastic coating applied or sprayed onto the entire or substantially the entire vapor barrier (i.e., onto the fleece layers of the individual vapor barrier sheets). The elastic coating thus forms a self-contained and continuous coating. Any unevenness caused by overlaps of the underlying vapor barrier sheets is therefore compensated for by the elastic coating. Consequently, the elastic coating has a continuous surface that does not exhibit potential weak points such as those found at the overlaps of waterproofing membranes.

All individual features or partial combination features relating to the arrangement disclosed herein are, as such, also combinable with the process features in any combination and are therefore disclosed. Conversely, all individual features or partial combination features relating to the process disclosed herein are, as such, also combinable with the arrangement features in any combination and are therefore disclosed.

Fig. 1

schematisch eine Anordnung zum Abdichten eines Dachs mit bestehendem Dachbelag,

Fig. 2

eine schematische, nicht maßstabsgerechte seitliche Schnittansicht der Anordnung aus Fig. 1 mit Entlüftung,

Fig. 3

eine schematische, nicht maßstabsgerechte seitliche Schnittansicht der Anordnung aus Fig. 1 mit einer Dampfsperre gemäß einer ersten Ausgestaltung,

Fig. 4

eine schematische, nicht maßstabsgerechte seitliche Schnittansicht der Anordnung aus Fig. 1 mit einer Dampfsperre gemäß einer zweiten Ausgestaltung,

Fig. 5

schematisch eine weitere Anordnung zum Abdichten eines Dachs mit bestehendem Dachbelag, und

Fig. 6

schematisch eine Anordnung zum Abdichten eines Kaltdachs mit bestehendem Dachbelag.

Embodiments of the invention are explained in more detail with reference to figures. The figures show:

Fig. 1

schematically an arrangement for sealing a roof with existing roofing material,

Fig. 2

a schematic, not to scale, side sectional view of the arrangement Fig. 1 with ventilation

Fig. 3

a schematic, not to scale, side sectional view of the arrangement Fig. 1 with a vapor barrier according to a first embodiment,

Fig. 4

a schematic, not to scale, side sectional view of the arrangement Fig. 1 with a vapor barrier according to a second embodiment,

Fig. 5

schematically, another arrangement for sealing a roof with existing roofing material, and

Fig. 6

Schematic representation of an arrangement for sealing a cold roof with existing roof covering.

Fig. 1 Figure 1 schematically shows an arrangement 20 for sealing a roof, in particular a flat roof, with an existing roof covering 21. The arrangement includes an existing roof covering 21 laid on a flat roof support such as a concrete slab 22. The roof covering 21 can be, as shown in Figure 22, Fig. 1 shown, for example, an existing vapor barrier or vapor retarder 23 and/or existing insulation 24 and/or an existing surface covering 26. Preferably, the vapor retarder 23 is laid directly on the concrete slab 22 and/or the insulation 24 is arranged between the surface covering 26 and the vapor barrier 23. As shown in Fig. 1 The top layer membrane 26 is shown to form the uppermost layer of the existing roof covering 21. A vapor barrier 2a is laid on the existing roof covering 21, or rather on the uppermost layer of the existing roof covering 21 (in this case, on the top layer membrane 26), or rather, it is bonded to the existing roof covering 21 by means of an adhesive coating 17. The structure of the vapor barrier 2a is described within the context of the Fig. 3 and the development of a possible alternative design of a vapor barrier 2b within the framework of Fig. 4 This will be explained in more detail below. The vapor barrier 2a is preferably designed in a sheet-like form.

The following is an example of how to install a sheet-like vapor barrier 2a, as described above, as a flat roof waterproofing system that acts as a vapor barrier. The sheet-like vapor barrier 2a can be cut to size before installation for easier handling. Alternatively, it can be installed directly from the roll.

The protective film of the full-surface adhesive coating 17 (see Fig. 3 The underlayment is applied to the existing roof covering 21, in particular the concrete slab 22, and the adhesive coating 17 is pressed onto the top surface of the concrete slab 22. Adjacent strips are preferably laid overlapping (at least 5 cm) to create a tight moisture barrier or vapor barrier. The overlap area must be carefully rolled. Fig. 1 (as well as the Figures 5 and 6 ) The vapor barrier 2a is shown as a continuous track for simplification.

Preferably, the existing roof covering 21 is cleaned before the vapor barrier 2a is glued on, i.e., loose parts are removed and/or the existing roof covering 21 is cleaned with water.

First, new insulation (not shown) can be laid on the existing roof covering 21 or on the existing top layer membrane 26, and the vapor barrier 2a can be glued onto this new insulation.

After the vapor barrier 2a has been glued in place, the top of the vapor barrier 2a, and in particular a fleece layer of the vapor barrier 2a (see Fig. 3 An elastic coating 16 made of polyurea or a polyurea mixture is applied. Preferably, the elastic coating 16 is sprayed on in liquid form. For example, the elastic coating 16 can be applied as a two-component system.

A surface protection (not shown), for example in the form of a gravel ballast, can be arranged on the upper side of the elastic coating 16.

Fig. 2 shows a schematic, not to scale, side sectional view of arrangement 20 from Fig. 1 with venting. The specifications described below also apply to arrangement 20a of the Fig. 5 and on order 20b of the Fig. 6 applicable. Furthermore, instead of the vapor barrier 2a shown, the vapor barrier 2b can also be used. Fig. 4 be used.

Preferably, before the vapor barrier 2a is adhered to the existing roof covering 21, perforations 34 are made in the existing roof covering 21 (i.e., the existing roof covering 21 is pierced from top to bottom, in particular the top layer 26, the insulation 24 and/or the vapor retarder or vapor barrier 23 are pierced). (pierced). This allows existing moisture in the existing roof covering 21 to rise to the newly applied vapor barrier 2a.

Preferably, at least one recess is made in the existing roof covering 21, preferably after perforation, and a venting element 32 with at least one inlet 32a and at least one outlet 32b is installed in the at least one recess before the vapor barrier 2a is bonded and the elastic coating 16 is applied. Preferably, the venting element 32 is installed in the recess such that, after the vapor barrier 2a has been bonded and the elastic coating 16 has been applied, an inlet 32a of the venting element is located below the vapor barrier 2a, 2b and an outlet 32b of the venting element is located above the elastic coating 16. This allows any moisture present below the vapor barrier 2a to escape upwards through the vapor barrier 2a and the elastic coating 16 via the venting element 32. The direction of flow of the escaping moisture or vapor is indicated by dashed arrows. Fig. 2 As shown. Thus, the existing roof covering 21 can be vented or dried by means of the venting element 32 after the vapor barrier 2a has been adhered and the elastic coating 16 has been applied. Preferably, a plurality of venting elements 32 are installed, particularly preferably in the edge area of the existing roof covering 21. Preferably, the inlet 32a is arranged within the insulation 24 (see Fig. 2 ).

For example, the venting element 32 can be designed as a pipe element, wherein the at least one inlet 32a and/or the at least one outlet 32b is arranged in a wall of the pipe element 32. As in Fig. 2 The pipe element 32, as shown, has a plurality of inlets in its wall and/or in a first end region of the pipe element 32 below the newly bonded vapor barrier 2a. Preferably, the pipe element has a plurality of outlets in its wall and/or in a second end region of the pipe element 32 above the elastic coating 16. The venting element 32 can include a fan (not shown) that is actively driven to generate an airflow between the inlet 32a and outlet 32b of the venting element. This allows moisture to be actively removed from the existing roof covering.

Fig. 3 shows a schematic, not to scale, side sectional view of arrangement 20 from Fig. 1 with the vapor barrier 2a and the elastic coating 16 according to a first embodiment.

The vapor barrier 2a has a moisture- and vapor-impermeable separating layer 4 made of aluminum and a fleece layer 12 bonded to the separating layer 4. The fleece layer 12 protects the vapor barrier and, in particular, the separating layer 4 from damage.

Preferably, the vapor barrier 2a has an adhesive coating 17, preferably a full-surface or nearly full-surface adhesive coating 17, on one side of the separation layer 4 facing away from the fleece layer 12. The vapor barrier 2a is adhered to the existing roof covering 21 and, in particular, to the existing top layer membrane 26 of the roof by means of the adhesive coating 17 (see Fig. 1 The vapor barrier is applied by overlapping the layers. This creates a very strong and fast-bonding 'adhesive-to-adhesive' connection. The adhesive used for the adhesive coating is preferably cold-curing and can be, for example, a bitumen- or butyl-based adhesive, an acrylate adhesive, or a hot-melt adhesive. These adhesives can be applied without problems down to -10°C.

For transport and protection of the full-surface adhesive coating 17, a protective cover (not shown) such as a protective paper (e.g. a liner) is preferably arranged on the full-surface adhesive coating 17, which can be peeled off for laying the vapor barrier 2a.

To ensure a tight seal between the end edges of the sheet-like vapor barrier 2a, the abutting end edges of adjacent sheets are overlapped by approximately 5 cm during installation. The long edges can then be covered with adhesive tape to create a vapor-tight and moisture-proof seal between the sheets. The adhesive tape has a width of, for example, 100–200 mm.

As in Fig. 3 As can be seen, a first protective layer 6 and/or a second protective layer 8 made of plastic can be formed on the side of the separation layer 4 facing away from the nonwoven layer 12. The first and/or second protective layer 6, 8 can be made of polyethylene terephthalate (PET) or high-density polyethylene (HDPE).

Preferably, an adhesive layer 10 is arranged between the second protective layer 8 and the nonwoven layer 12, which is selected from the group of polyolefins, such as PP.

The different layers can be bonded in various ways. Bonding, laminating, spraying, fusing, bonding, or hot stamping are particularly advantageous. Different of these methods can also be used between the individual layers to bond them together.

The two protective layers 6, 8 are preferably alkali-resistant. Since the two protective layers 6, 8 enclose the separating layer made of aluminum 4, the non-alkali-resistant aluminum is protected from damage by the protective layers 6, 8.

• erste Schutzlage 6: PET-Schicht, ca. 12 µm,
• Aluminium-Trennlage 4: ca. 7 µm,
• zweite Schutzlage 8: PET-Schicht, ca. 25 g/m²,
• Kleberschicht 10: aus einem Kunststoff der Gruppe der Polyolefine wie beispielsweise PP,
• Vlieslage 12: PP-Spinnvlies, Flächendichte ca. 100 g/m²,
• Kleberbeschichtung 17: Bitumen oder Butylkleber, Stärke: 0,3 mm,
• Bahnbreite x Länge x Dicke: 1,5 m x 100 m x 0,20 mm,

For example, the vapor barrier 2a can have the following structure:

• First protective layer 6: PET layer, approx. 12 µm,
• Aluminum separating layer 4: approx. 7 µm,
• second protective layer 8: PET layer, approx. 25 g/ ^m² ,
• Adhesive layer 10: made of a plastic from the polyolefin group, such as PP,
• Fleece layer 12: PP spunbond, surface density approx. 100 g/m ² ,
• Adhesive coating 17: Bitumen or butyl adhesive, thickness: 0.3 mm,
• Web width x length x thickness: 1.5 m x 100 m x 0.20 mm

As described above, the elastic coating 16 made of polyurea or a polyurea mixture in liquid form is applied or sprayed onto the fleece layer 12 of the vapor barrier 2a.

Fig. 4 shows a schematic, not to scale, side sectional view of the arrangement. Fig. 1 with a vapor barrier 2b and the elastic coating 16 according to a second embodiment.

Unlike the one in the Figures 1 to 3 and Figures 5 and 6 In contrast to the vapor barrier 2a shown, this vapor barrier 2b has a second protective layer 8 made of LDPE instead of the second protective layer 8 made of PET and the adhesive layer 10. Unless otherwise noted, all other specifications of vapor barrier 2b correspond to those of Fig. 4 those who are in the Figures 1 to 3 , 5 and 6 vapor barrier 2a as described. As in Fig. 4 As shown, the vapor barrier 2b preferably has a fabric layer 14 which is sandwiched between the fleece layer 12 and the second protective layer 8 is arranged. Although arrangements 20, 20a, 20b of the Figures 1 to 3 , 5 and 6 Each is shown with the vapor barrier 2a, however, arrangements 20, 20a, 20b can also have the vapor barrier 2b instead of the vapor barrier 2a.

• erste Schutzlage 6: PET-Schicht, ca. 12 µm,
• Aluminium-Trennlage 4: ca. 7 µm,
• zweite Schutzlage 8: LDPE-Schicht, Flächengewicht ca. 35 g/m²,
• Gewebelage 14: Flächengewicht ca. 60 g/m²,
• Vlieslage 12: PP-Spinnvlies, Flächendichte ca. 100 g/m²,
• Kleberbeschichtung 17: Bitumen oder Butylkleber, Stärke: 0,3 mm,
• Bahnbreite x Länge x Dicke: 1,5 m x 100 m x 0,20 mm,

For example, the vapor barrier 2b can have the following structure:

• First protective layer 6: PET layer, approx. 12 µm,
• Aluminum separating layer 4: approx. 7 µm,
• Second protective layer 8: LDPE layer, basis weight approx. 35 g/ ^m² ,
• Fabric layer 14: Basis weight approx. 60 g/ ^m² ,
• Fleece layer 12: PP spunbond, surface density approx. 100 g/m ² ,
• Adhesive coating 17: Bitumen or butyl adhesive, thickness: 0.3 mm,
• Web width x length x thickness: 1.5 m x 100 m x 0.20 mm

Preferably, the LDPE layer 8 is applied in liquid form to the release layer 4, and the fabric layer 14 and nonwoven layer 12 are placed onto the still liquid LDPE layer 8. This allows the liquid LDPE to penetrate the fabric layer 14 and the nonwoven layer 12, and after curing, they are firmly bonded to the release layer 4.

Fig. 5 Figure 20a schematically shows an arrangement 20a for sealing another roof, in particular a flat roof, with existing roof covering 21. The arrangement 20a of the Fig. 5 differs from arrangement 20 of the Figs. 1 and 2 by the fact that the existing roof covering 21 is laid on a trapezoidal sheet 30. Unless otherwise noted, all other specifications regarding the existing roof covering 21, the vapor barrier 2a, the elastic coating and the ventilation elements 32 correspond to Fig. 5 those in Figs. 1 and 2 .

Fig. 6 Figure 20b schematically shows an arrangement for sealing a cold roof with an existing roof covering 21a. The arrangement 20b of the Fig. 6 differs from arrangement 20 of the Fig. 1 through the existing roof covering 21a. Unless otherwise noted, all other specifications regarding the vapor barrier 2a and the elastic coating and the ventilation elements correspond to Fig. 6 those in Figs. 1 and 2 The existing roof covering 21a of arrangement 20b is as shown in Figs. 1 and 2 laid on the concrete slab 22. The existing roof covering 21a can be, as in Fig. 6 shown, for example, an existing vapor barrier or vapor retarder 23 and/or existing insulation 24 and/or an existing top layer 26. Preferably, the vapor retarder 23 is laid directly on the concrete slab 22.

The existing roof covering 21a further comprises beam elements 31 arranged on the vapor barrier 23 and a wooden sheathing 27 laid on the beam elements. The insulation 24 is arranged between the vapor barrier 23 and the wooden sheathing 27. The wooden sheathing 27 and the beam elements 31 are designed such that the wooden sheathing 27 is spaced apart from the underlying insulation 24 (i.e., a cavity 29 is present between the insulation 24 and the wooden sheathing 27). The top layer 26 is arranged on the wooden sheathing 27. Preferably, a separating layer 28, for example a PE film, can be laid between the wooden sheathing 27 and the top layer 26. The top layer 26 is arranged similarly to the Figures 1, 2 and 5 The new vapor barrier 2a was glued on, on which the elastic coating 16 was applied.

For the sake of simplicity, the perforations in the existing roof covering 21, 21a are shown in the instructions 20a, 20b of the Figures 5 and 6 not shown. Similar to Fig. 2 Here too, perforations are preferably introduced that penetrate the top layer 26, the vapor barrier 23, and all intermediate layers, so that moisture can rise from the existing roof covering 21, 21a to the newly applied vapor barrier and, particularly preferably, escape upwards from the roof via the ventilation elements 32. The specifications regarding the ventilation elements 32 of the Fig. 2 are also subject to provisions 20a and 20b of the Figures 5 and 6 applicable unless otherwise stated.

Reference symbol list

2a, 2b

vapor barrier

4

Aluminum separating layer

6

first line of defense

8

second layer of protection

10

Adhesive layer

12

fleece layer

14

Tissue layer

16

elastic coating made of polyurea or polyurea mixture

17

(Full-surface) adhesive coating

20, 20a, 20b

Flat roof arrangement

21, 21a

existing roof covering

22

Flat roof beams (concrete ceiling)

23

existing vapor barrier / vapor retarder

24

existing insulation

26

existing surface track

27

wooden formwork

28

Separation layer

29

cavity

30

Trapezoidal sheet metal

31

Beam element

32

venting element

32a

inlet

32b

Outlet

34

Perforation

Claims (15)

Arrangement (20, 20a, 20b) for sealing a roof, in particular a flat roof, with existing roof covering (21, 21a), comprising: a roof (22, 30) with existing roof covering (21, 21a); a vapor barrier (2a, 2b) on the existing roof covering, comprising: a moisture-impermeable and/or vapor-barrier separating layer (4) made of aluminium, a nonwoven layer (12) connected to the separation layer, and an adhesive coating (17) arranged on one side of the separation layer (4) facing away from the nonwoven layer (4); and an elastic coating (16) made of polyurea or a polyurea mixture, which is arranged on the vapor barrier (2a, 2b), preferably on the nonwoven layer (12) of the vapor barrier (2a, 2b); wherein the vapor barrier (2a, 2b) is bonded to the existing roof covering (21, 21a) of the roof with the adhesive coating (17). Arrangement according to claim 1, wherein the adhesive coating (17) is designed as a full-surface or substantially full-surface adhesive coating (17), and/or wherein the adhesive coating (17) is formed from a hot melt adhesive or from an acrylate adhesive or from an adhesive based on bitumen or butyl, and/or wherein the adhesive coating (17) has a thickness in the range of 0.1 mm - 2.0 mm, 0.1 mm - 0.6 mm, 0.5 mm - 1.0 mm, 0.9 mm - 1.4 mm, 1.3 mm - 2.0 mm, particularly preferably 0.3 mm. Arrangement according to claim 1 or 2, wherein the vapor barrier (2a, 2b) is formed from adjacent, web-shaped individual webs, preferably from single strips laid side by side, each or predominantly with a width of at least 100 cm, 110 cm, 120 cm, 140 cm or 150 cm, and wherein the vapor barrier (2a, 2b) is preferably formed from two, three, four, five or more individual sheets laid side by side, wherein adjacent layers of the vapor barrier (2a, 2b) are particularly preferably laid overlapping in their edge area, in particular with an overlap area of at least 30 mm, 40 mm, 50 mm, 70 mm or 90 mm. Arrangement according to one of the preceding claims, wherein the vapor barrier comprises (2a, 2b): a first protective layer (6) which is connected to and/or applied to the side of the separating layer (4) facing away from the nonwoven layer (12), and/or a second protective layer (6) arranged between the separating layer (4) and the nonwoven layer (12). Arrangement according to one of the preceding claims, wherein the elastic coating (16) is applied or sprayed on as a full-surface and/or self-contained coating on the vapor barrier (2a, 2b). arrangement according to one of the preceding claims, wherein the elastic coating (16) comprises 90 to 100 wt.%, 90 to 95 wt.% or 95 to 100 wt.% polyurea or a polyurea mixture comprising 1 to 95 wt.%, 30 to 97 wt.%, 50 to 95 wt.% or 75 to 95 wt.% polyurea, and/or wherein the polyurea or polyurea mixture comprises components of polyurethane, polyphenol, polyolefin, polypropylene, polyethylene, polystyrene, polyester, polyethylene oxide, polyterephthalate, polyacrylic, polyamide or polycarbonate as a single component or as a mixture of various such substances. Arrangement according to claim 6, wherein the polyurea mixture comprises flame-retardant substances, preferably in the form of inorganic salts or organometallic compounds, particularly preferably substances selected from the group consisting of calcium carbonate, aluminium trihydrate, magnesium hydroxide, sodium and/or potassium hydroxide stannate. arrangement according to one of the preceding claims, wherein the elastic coating (16) is weatherproof and in particular waterproof and/or UV-resistant, and/or wherein the elastic coating (16) has high abrasion resistance and/or is scratch-resistant, and/or wherein the elastic coating (16) has a thickness in the range of 1-8 mm, 1-4 mm, 2-5 mm, 3-6 mm, 4-8 mm, preferably 2.5 mm, and/or wherein between the existing roof covering (21, 21a), preferably between an existing top layer membrane, and the vapor barrier (2a, 2b) a newly applied insulation is laid on the existing roof covering, wherein in particular the vapor barrier is glued onto the newly applied insulation. arrangement according to one of the preceding claims, where the existing roof covering (21, 2a) is at least partially perforated, and/or wherein the arrangement (20, 20a, 20b) has at least one venting element (32) with an inlet (32a) and an outlet (32b) arranged such that the inlet (32a) is located below the vapor barrier (2a, 2b) and the outlet (32b) is located above the elastic coating (16), so that moisture and/or vapor can escape upwards from below the vapor barrier (2a, 2b) via the venting element (32) through the vapor barrier (2a, 2b) and the elastic coating (16). Method for sealing a roof with existing roof covering (21, 21a), comprising: Applying a vapor barrier (2a, 2b) to the existing roof covering (21, 21a), wherein the vapor barrier (2a, 2b) has: a moisture-impermeable and/or vapor-barrier separating layer (4) made of aluminium, a nonwoven layer (12) connected to the separating layer (4), and an adhesive coating (17) which is arranged on one side of the separating layer (4) facing away from the nonwoven layer (12), wherein the vapor barrier (2a, 2b) is bonded to the existing roof covering (21, 21a) of the roof with the adhesive coating (17), and subsequent application of an elastic coating (16) of polyurea or a polyurea mixture to the vapor barrier (2a, 2b), preferably to the nonwoven layer (12) of the vapor barrier (2a, 2b). The method of claim 10, wherein the method further comprises: Cleaning the existing roof covering (21, 21a) before applying the vapor barrier (2a, 2b), preferably with water, and particularly preferably with a steam cleaner or high-pressure cleaner, and/or direct bonding, preferably after cleaning, of at least one vapor barrier (2a, 2b) onto the existing roof covering (21, 21a). The method of claim 10 or 11, wherein the method further comprises:
Perforating the existing roof covering (21, 21a) before applying the vapor barrier (2a, 2b), preferably after cleaning the roof covering (21, 21a), so that any moisture present in the roof covering (21, 21a) can rise to the newly applied vapor barrier (2a, 2b). The method of claim 10, 11 or 12, wherein the method further comprises: Creating at least one recess in the existing roof covering (21, 21a), and Mounting a venting element (32) in the at least one recess before bonding the vapor barrier (2a, 2b) and applying the elastic coating (16), wherein the venting element (32) is mounted in the recess such that an inlet (32a) of the venting element is located below the vapor barrier (2a, 2b) and an outlet (32b) of the venting element is located above the elastic coating (16), so that any moisture present below the vapor barrier (2a, 2b) can escape upwards via the venting element (32) through the vapor barrier (2a, 2b) and the elastic coating (16). Method according to any one of claims 10 to 13, wherein the elastic coating (16) is applied in liquid form, preferably by spraying, and/or wherein the elastic coating (16) is produced by applying a mixture of two starting components to the vapor barrier (2a, 2b), wherein the starting components are preferably mixed directly in the nozzle head of an application device before the resulting mixture is applied to the vapor barrier, preferably to the nonwoven layer of the vapor barrier. Method according to any one of claims 10 to 14, wherein the vapor barrier (2a, 2b) is formed from adjacent, web-shaped individual webs, and wherein the method comprises:
Adhering two or more adjacent strips of vapor barrier (2a, 2b) prior to applying the elastic coating (16), wherein adjacent strips of vapor barrier (2a, 2b) are particularly preferably laid overlapping in their edge area, in particular with an overlap area of at least 30 mm, 40 mm, 50 mm, 70 mm or 90 mm.