EP2256266B1 - Roof underlay for a sloping roof - Google Patents

Description

Technical area

The invention relates to a Unterdeckbahn for a sloping roof with a water and water vapor permeable support layer and a waterproof and wasserdampfdurchläs-sigen sealing layer based on TPU. Furthermore, the invention relates to a roof with a plurality overlapped laid and welded, waterproof and water vapor permeable underlay webs.

State of the art

Underdecks have the task of initially protecting the uncovered roof from rainfall. After the hard roofing, the input of flying snow, spray and condensation water and fine dust particles in the thermal insulation should be prevented. At the same time, water vapor, which can originate as a wet surplus from the building moisture and from inhabited areas of the roof, can be released to the environment via the diffusive heat insulation and the underlay membrane. In this case, the entire, mounted between the rafters thermal insulation can serve as a temporary moisture storage, it should be noted that the dew point at which condensation is deposited, is not exceeded. This can be prevented by installing a vapor barrier or brake under the roof into the roof construction.

If the laid underlay membrane has no or too little permeability to water vapor, there may be a moisture surplus in the roof area on the underlay membrane condense, moisturize the insulation and thus, inter alia, reduce their function.

For underlay membranes, a distinction is made among other things between waterproof underlay membranes and rainproof underlay membranes. Although rainproof roof coverings are as a rule rainproof, they can not completely prevent the input of driving rain and driving snow in extreme locations or in special weather conditions. A sub-roof is considered to be rainproof if its surface, including the seam and butt joints between individual roofing membranes, is rainproof. In the rainproof under-roof penetrations, built-in parts and borders are rainproof.

In contrast, in the waterproof sub-roof penetrations, built-in parts and enclosures must be waterproof, so that the entire sub-roof is impermeable to water. Only in this way can one speak of a watertight roof construction as a whole, because the usual shingled roof coverings are normally only rainproof and can not completely prevent the inrush of driving rain and driving snow, among other things.

Among other things, plastic sheets are used to produce a watertight underlay, in particular TPUs, ie urethane-based thermoplastic elastomers, because they are particularly water and heat-resistant, soft and flexible, therefore easy to process and, in particular, resistant to microbes. In order to join together two adjacent TPU underlay webs, they are glued together, which requires the presence of an adhesive in or on the TPU layer.

However, there are also Unterdeckbahnen that a sealing layer based on TPO (thermoplastic elastomers on Olefinbasis). Such underlay sheets are also thermally welded together.

Another property of the sealing layer is, in addition to the waterproofness, the water vapor permeability, which is also referred to as diffusion openness. This means that although the sealing layer is impermeable to water which may strike the underlay from the outside, water vapor from the interior of the building can escape to the outside due to the diffusion-open nature and thus an impairment of the thermal insulation or of other objects present in the interior of the building avoids too high humidity.

The underlay webs often still have a carrier layer, which is permeable to water and water vapor. A layer composite of a carrier layer and a sealing layer can be waterproof and permeable to water in a watertight and water vapor-permeable sealing layer as a whole, so that a vapor-permeable and watertight embodiment of a sub-roof can be realized.

US 2005/0097857 A1 discloses a non-asphalt, especially non-bitumen, underlay for a roof that is vapor-permeable and waterproof. One or two layers of a vapor-permeable thermoplastic material can be applied to a substrate layer.

DE 79 07 342 U1 describes a bituminous roofing sheet having on one longitudinal edge an uncovered, untrimmed, bare bituminous layer for waterproof connection to a following sealing layer.

DE 38 23 365 A1 discloses a roof covering element in the form of a rectangular insulating panel made of heat-insulating material, which serves to shorten the assembly time on site a serving for sealing the roof sealing membrane directly on the top of the insulation board is laminated. The sealing sheet is for sealing connection with the adjacent insulation boards on two adjacent edges on the insulation board over.

Presentation of the invention

The underlaid webs known from the prior art have the disadvantage that they can be connected to one another in a watertight and permeable manner only with relatively high outlay. In particular, additional adhesives must be provided for the watertight and diffusion-open connection between underlay webs with a TPU-based sealant layer. On the other hand, the TPO-based weldable underlay membranes do not have the advantages of the TPU layer, which includes the special water and heat resistance, the soft and flexible structure and therefore good processability and microbial resistance.

The object of the present invention is to provide a sub-roof sheet associated with the above technical field, which enables an efficient realization of a watertight and water-vapor-permeable sub-roof.

The object is solved by the subject matter of claims 1, 10, 11 and 14 and 15. Preferred embodiments of the subject invention are defined by the dependent claims.

According to the invention, a underlay for an inclined roof with a water and water vapor permeable support layer and a waterproof and water vapor permeable sealing layer based on TPU characterized in that the thickness of the sealing layer is dimensioned such that the underlay web with another similar underlay by thermal welding and solvent welding is waterproof and permeable to water.

In this case, the underlayer web has a watertight and water vapor-permeable connection strip along at least one of the edges of the carrier layer, which projects beyond this at least one edge, and both the TPU of the sealing layer and the TPU of the connection strip is an aromatic TPU.

An inclined roof is understood to mean a roof which, according to DIN 1055, has a slope of more than 7 degrees. Despite the inclination of the roof, it is advantageous or even necessary for certain weather conditions to provide not only a rainproof, but a waterproof underlayment to effectively prevent driving snow, driving rain, icing and snow deposits and the like.

As a particularly preferred material for such a Unterdeckbahn the waterproof and water vapor permeable TPU is used which has the advantages already mentioned above. By means of the embodiment according to the invention, it is possible to heat adjacent underlaid webs thermally or by means of solvent welding and thus to assemble them in a watertight and water vapor permeable manner.

To TPU within the meaning of the invention are also mixtures with a share of at least 80 wt .-% TPU and up to 20 wt .-% filler count. Corresponding fillers can be used for example to save material and / or cost reduction.

To assess whether a roofing membrane can be described as watertight, DIN 1928 and DIN 20811 are to be used. If tests are fulfilled hereafter, the tracks are considered watertight. Likewise, the waterproofness and thus the use of the invention is significantly defined by the requirements of the ZVDH (Central Association of German Dachdeckerhandwerkes), which provides for the existence of a defined impact rain test at the TU Berlin.

The standard to be considered for diffusion openness is DIN 4108, Part 3. There, Sd <0.5 m is defined as the limit value for diffusion openness. Thus, a layer whose Sd value is less than 0.5 m is to be designated as diffusion-open.

However, the Sd value is preferably less than 0.2 m. According to DIN 68800, Sd <0.2 m must be adhered to and a corresponding layer must be regarded as permeable to vapor if chemical wood preservatives are to be dispensed with.

Particularly preferably, the Sd value of the underlay web is less than 0.2 m and is between 0.02 m and 0.2 m.

During thermal welding, the temperature of the TPU layer is increased in such a way that it combines with another corresponding layer and thus is homogeneously welded. In solvent welding, a swelling agent, e.g. As tetrahydrofuran (THF), on the Sealing layer given, which dissolves the TPU and thereby allows welding between adjacent Unterdeckbahnen. In addition, for example, benzene or gasoline can be used. However, among others, THF is particularly preferred over benzene or gasoline or other solvents due to its short exposure time and associated short time required for laying. Preferred solvents may generally be included among the alkanes, alkenes, aromatics, organochlorine compounds, alcohols, esters, ethers or ketones.

The underlay of the invention preferably consists of a water- and water vapor-permeable support layer and a waterproof and water vapor permeable sealing layer and requires neither an additional adhesive layer as a connecting means with another underlayment still another, the stability of the underlayer web increasing layer.

In underlay webs according to the preamble of claim 1, the support layer provides for the stability of the underlay web, whereas the sealing layer is responsible for ensuring that the undercover web is waterproof and permeable to water vapor. The material used for the sealing layer based on TPU is relatively expensive, so that conventionally care is taken to make the sealing layer as thin as possible in the context of the requirements in terms of their sealing property.

According to the invention deviates from this principle and increases the thickness of the sealing layer over the prior art. The thickness of the sealing layer is increased so much that thermal welding is also possible with a sealing layer based on TPU, without the sealing layer or the carrier layer being damaged during thermal welding. This would be done in the case of a conventional underlay web with a correspondingly thin sealing layer, so that conventional underlay webs by thermal welding can not be connected. The same applies to the source welding, which for the same reasons is not applicable to a sealing layer based on TPU with too small a thickness.

In order to be able to assemble adjacent underlay webs as efficiently as possible, the waterproof and water vapor-permeable connection strip according to the invention is provided along at least one of the edges of the carrier layer, which protrudes beyond this edge.

This connection strip can, for example, be placed on hot TPU during production of the underlay web, which is already located on the carrier layer, and thereby connects to the TPU of the sealing layer. In addition, it is also possible, for example, that the connecting strip is made integral with the sealing layer, that is, the sealing layer as such extends correspondingly over at least one of the edges of the carrier layer such that a corresponding connection strip is formed. In addition, there are other ways to connect or create the connection strip with the underlay web, e.g. by removing cover layer material or removing backing layer from the underlay web.

Because the connecting strip is also made of a waterproof and water vapor permeable material, it is possible waterproof and water vapor permeable together assemble a lower cover sheet with another Unterdeckbahn, so that a sub-roof can be made completely waterproof and permeable to water vapor. The connecting strip as part of the underlay web allows a particularly efficient connection between adjacent underlay webs, because here no additional adhesive or another connecting element has to be placed on the adjacent underlay webs.

The characteristics "watertight" and "permeable to water vapor" or "permeable to diffusion" are based on the building inspectorate guidelines that apply to roofs in Germany. Corresponding standards can be found, for example, in DIN 68800 and DIN 4108, Part 3, and should also be used in this context to define the above-mentioned properties.

The connection strip is a TPU-based strip. The TPU-based connection strip also provides watertight and water-vapor permeable roof coverage at the welds with all the advantages of the TPU and facilitates the welding of adjacent underlay webs.

Both the TPU of the sealing layer and the TPU of the connecting strip is an aromatic TPU, wherein preferably the sealing layer and the connecting strip are made of the same material. Aromatic TPU is particularly well suited for welding and has the above-mentioned particularly preferred properties of a TPU-based sealing layer.

Advantageously, the sealing layer has a thickness of at least 0.1 mm, preferably 0.1 to 0.2 mm, particularly preferably 0.1 to 0.15 mm. Such a thickness of the sealing layer of the underlay web is suitable for connecting adjacent underlay webs to one another by welding, without the sealing layer and / or the carrier layer being damaged in the process. In addition, the claimed thickness is at the same time suitable for the efficient production of a underlay web, since no excess material is applied to the carrier layer.

Advantageously, the sealing layer has a mass areal density of at least 100 g / m ² , preferably 100 to 200 g / m ² , particularly preferably 100 to 150 g / m ² . Corresponding mass surface densities mean that, compared to conventional sealing layers of a lower cover sheet of the preamble of claim 1, a mass application has taken place which makes adjacent lower cover webs connectable to one another by thermal welding or solvent welding.

Preferably, the underlay web is adhesive-free. In conventional underlay membranes with a TPO-based sealing layer, some kind of adhesives are required in order to bond the underlay membrane to an adjacent underlay membrane. Although the term "welding" is occasionally used in the prior art, this is in fact bonding, since it is not the TPO layers of the corresponding sealing layers that are connected directly and directly to one another, but an adhesive is incorporated into the underlay web is that optionally produces a watertight connection between adjacent Unterdeckbahnen.

In a preferred embodiment, the connecting strip protrudes by at least 3 cm, preferably by between 3 cm and 7 cm, particularly preferably by between 5 cm and 7 cm beyond the at least one edge. A connecting strip, which extends beyond the edge by the above-mentioned value, allows a secure connection between adjacent underlay webs, so that the entirety of the underlaid webs can be made waterproof and permeable. It thus meets the building supervisory requirements for a watertight welding of two underlay membranes with each other.

In a preferred embodiment, the connecting strip is made integral with the sealing layer. As described above, such a connection strip is laid on the hot TPU, for example during the production of the underlaid web, or produced as a part of the sealing layer projecting beyond the carrier layer.

Another preferred embodiment provides that the connection strip is joined to the sealing layer by thermal welding and / or solvent welding. In this preferred embodiment, the connecting strip can be connected after cooling of the sealing layer with the sealing layer. The connecting strip can thus be connected by the same mechanism with the sealing layer, as adjacent lower cover webs can be interconnected. In this way, existing underlay webs with a corresponding thickness of the sealing layer can also be retrofitted with a connection strip according to the invention. However, the laying of the underlay web is simplified because the connecting strip only needs to be welded to one edge of a underlay web and not with two abutting edges of two underlay webs.

The carrier layer is preferably a nonwoven. The basis of the nonwoven may preferably be polyester or a polyester-containing mixed fiber or a derivative thereof. On the one hand, a carrier layer of nonwoven makes possible a particularly simple production of the underlaid web, in that the sealing layer can be applied to the then existing carrier layer without the sealing layer itself having to be particularly stable. This also allows large-area underlay webs to be efficiently produced. On the other hand, the carrier layer of occupational safety when laying the underlay sheets, because it brings an additional strength in the underlay, so that the underlay can easily carry an adult human, when this occurs on the underlay. In principle, the underlay web according to the invention can be used for all applications which require watertight and water-vapor-permeable undervoltages. In particular, can be dispensed with the provision of a waterproof and vapor-permeable underlay web on wood preservative to protect the roof construction. The underlay sheet according to the invention enables a particularly efficient laying of a lower roof as well as an efficient production of the underlay sheets. Adjacent underlaid webs can be directly connected to one another by means of the connecting strip, whereby they are also watertight and permeable at the point of connection, namely the overlap between the connecting strip and the adjacent underlaid web.

In principle, it is also possible that the underlay web has more than two layers, wherein it is preferred that it contains only one carrier layer and one sealing layer. Depending on the field of application, however, it may be advantageous to provide one or more further layers either on the sealing layer, between the sealing layer and the carrier layer or under the carrier layer. In order to ensure the waterproofness and diffusion-openability of the underlay web in a multi-layered design, however, care must be taken to ensure that the additionally attached layers are at least permeable to water vapor and do not impair the watertightness of the sealing layer.

The underlay web according to the invention can also have a plurality of connecting strips which project beyond a plurality of edges of the carrier layer. This can be provided, for example, in corner pieces of underlay sheets or in special undercover elements for sealing penetrations, built-in parts or enclosures.

An inventive roof contains a plurality overlapped laid and welded, waterproof and water vapor permeable underlay sheets, as described above. In this case, the connecting strip of a bottom cover web is welded to an adjacent bottom cover web in such a way that the bottom cover webs have a watertight and water vapor permeable welded connection. In this case, the connection strip is preferably formed integrally with the sealing layer of the associated underlayment, so that welding only has to take place on one side of the connection strip. Such a roof can be classified as waterproof according to the ZVDH guidelines and is therefore suitable for effectively protecting a building from moisture even in particularly unfavorable weather conditions.

Further preferred embodiments will become apparent from the totality of the claims and the following description of the figures.

Short description of the figures

Fig. 1A

shows a side view in cross section of a preferred roofing membrane for a sloping roof;

Fig. 1B

shows a side view in cross section of another preferred roofing membrane for a sloping roof;

Fig. 1C

shows a side view in cross section of another preferred roofing membrane for a sloping roof;

Fig. 2

shows a plan view of two joined Unterdeckbahnen; and

Fig. 3

shows a plan view of a corner piece of a preferred underlay web.

Ways to carry out the invention

Fig. 1A shows a side view of a preferred underlay web 10 in a cross-sectional view. On a carrier layer 12, a sealing layer 14 is arranged, which is designed on TPU basis. On the sealing layer 14 is located along an edge 15, a connecting strip 16, which extends on both sides of the edge 15.

In this case, the connecting strip 16 extends around the distance 18 via the sealing layer 14 of the underlay web 10 and projects beyond the edge 20 of the carrier layer 12 by the distance 20. The thickness 24 of the sealing layer 14 is in Fig. 1A shown as slightly smaller than the thickness 23 of the carrier layer 12. In contrast, the thickness 22 of the connecting strip 16 corresponds to the thickness 24 of the sealing layer 14.

The connecting strip 16 and the sealing layer 14 are not only the same thickness, but also made of the same material, namely preferably aromatic TPU. The carrier layer 12 is made of a non-woven.

The distance 18 or 20 of the connecting strip 16 is in the in Fig. 1A illustrated embodiment each 5 cm, the thickness 22 of the connecting strip 16, as well as the thickness 24 of the sealing layer 14, 0.15 mm. The sealing layer 14 has a mass areal density of 150 g / m ² .

Fig. 1B shows a side view of a preferred Unterdeckbahn 10 in a cross-sectional view, the Fig. 1A similar. In Fig. 1B However, another preferred embodiment is shown in which the connection strip 16 is formed integrally with the sealing layer 14. The thickness 22 of the connecting strip 16 in this embodiment is equal to the thickness of the sealing layer 14. The connecting strip 16 extends as shown in FIG Fig. 1A illustrated embodiment, also to the Projection 20 over the edge 15 of the carrier layer 12. Incidentally, the description of the Fig. 1A directed.

Fig. 1C shows a further embodiment of a preferred Unterdeckbahn 10 in a cross-sectional view, the Fig. 1A and 1B similar. In Fig. 1C However, it is the connection strip 16, as in the embodiment of Fig. 1B is integrally formed with the sealing layer 14, folded and attached to the support layer 12 on the sealing layer 14 opposite side. Incidentally, this embodiment corresponds to in Fig. 1B shown.

Fig. 2 shows a plan view of two adjacent underlay webs 10.1, 10.2, which are interconnected by a connecting strip 16.1 of the first underlay web 10.1. On the connection strip 16.1 of the first lower deck 10.1 opposite side of the second Unterdeckbahn 10.2 is the connecting strip 16.2 of the second Unterdeckbahn 10.2. Thus, a further underlayment web along the edge of the second underlap web 10.2, which is provided with the connecting strip 16.2, could be applied to the second underlap web 10.2 and joined together therewith.

The underlay webs 10.1, 10.2 extend parallel to the edge along which the connecting strips run 16.1 and 16.2. Due to the waterproof and diffusion-open connection of the two underlay webs 10.1 and 10.2 and the entirety of the underlay webs 10.1 and 10.2 is classified as waterproof and permeable.

Fig. 3 shows a preferred embodiment of a lower cover sheet 10, in which a connecting strip 16 along second edges 26 and 28 of the lower cover sheet 10 extends. The two edges 26 and 28 of the underlay web 10 run thereby in the in Fig. 3 illustrated embodiment at right angles to each other.

Thus, by the in Fig. 3 shown embodiment on the one hand a waterproof and diffusion-open connection between longitudinally adjacent underlay webs together along the edge 26, on the other hand, it is also possible to connect successively underlying underlays 10 along the edge 28 by the connecting strip 16 waterproof and permeable to water vapor.

The embodiments shown in the figures can be varied geometrically in almost any desired manner, so that in particular curved or angled underlay webs can be executed.

Claims (15)

1. Underlay (10) for a sloping roof having a water-permeable and water vapour-permeable support layer (12) and a water-tight and water vapour-permeable sealing layer (14) based on TPU, characterised in that the thickness of the sealing layer (14) has dimensions such that the underlay (10) can be joined to a further similar underlay (10) by thermal welding and solvent welding to be water-tight and water vapour-permeable, wherein the underlay (10) has a water-tight and water vapour-permeable connecting strip (16) based on TPU along at least one of the edges of the support layer (12) which projects beyond this at least one edge, wherein both the TPU of the sealing layer (14) and the TPU of the connecting strip (16) is an aromatic TPU.
2. Underlay (10) according to claim 1, wherein the sealing layer (14) and the connecting strip (16) are made from the same material.
3. Underlay (10) according to claim 1 or 2, wherein the sealing layer (14) has a thickness of at least 0.1 mm, preferably 0.1-0.2 mm, particularly preferably 0.1-0.15 mm.
4. Underlay (10) according to one of the preceding claims, wherein the sealing layer (14) has a weight per unit area of at least 100 g/m², preferably 100-200 g/m², particularly preferably 100-150 g/m².
5. Underlay (10) according to one of the preceding claims, wherein the underlay (10) is free of adhesive.
6. Underlay (10) according to one of the preceding claims, wherein the connecting strip (16) projects by at least 3 cm, preferably by between 3 cm and 7 cm, particularly preferably by between 5 cm and 7 cm, beyond the at least one edge.
7. Underlay (10) according to one of the preceding claims, wherein the connecting strip (16) is designed to be integral with the sealing layer (14).
8. Underlay (10) according to one of claims 1 to 7, wherein the connecting strip (16) is joined to the sealing layer (14) by thermal welding and/or solvent welding.
9. Underlay (10) according to one of the preceding claims, wherein the support layer (12) is a non-woven.
10. Roof having a plurality of water-tight and water vapour-permeable underlays (10.1, 10.2) laid and welded to be overlapping according to one of the preceding claims, wherein the connecting strip (16.1) of an underlay (10.1) is welded to an adjacent underlay (10.2) such that the underlays (10.1, 10.2) have a water-tight and water vapour-permeable welded joint.
11. Method for producing an underlay (10) for a sloping roof according to one of claims 1 to 9, comprising the following steps:

    applying a water-tight and water vapour-permeable sealing layer (14) based on aromatic TPU to a water-permeable and water vapour-permeable support layer (12) and

    joining a water-tight and water vapour-permeable connecting strip (16) based on aromatic TPU to the sealing layer (14) along at least one of the edges of the support layer (12), so that the connecting strip (16) projects beyond the edge.
12. Method according to claim 11, further comprising heating of the sealing layer (14) before the connecting strip (16) is joined to the sealing layer (14), wherein the connecting strip (16) is joined to the sealing layer (14) by placing on the heated sealing layer (14) along at least one of the edges of the support layer (12).
13. Method according to claim 11, wherein the connecting strip (16) is joined to the sealing layer (14) by thermal welding and/or solvent welding along at least one of the edges of the support layer (12).
14. Method for producing an underlay (10) for a sloping roof according to one of claims 1 to 9, comprising the following steps:

    applying a water-tight and water vapour-permeable sealing layer (14) based on aromatic TPU to a water-permeable and water vapour-permeable support layer (12), wherein the sealing layer (14) projects beyond at least one edge of the support layer (12) such that a water-tight and water vapour-permeable connecting strip (16) is formed, wherein the connecting strip (16) is formed preferably by withdrawing material of the sealing layer (14) opposite at least one of the edges of the support layer (12) and/or by removing material of the support layer (12) opposite the sealing layer (14) along at least one of the edges of the support layer (12).
15. Method for laying several overlapping underlays (10) according to one of claims 1 to 10 on a roof, wherein the connecting strip (16.1) of an underlay (10.1) is thermally welded and/or solvent-welded to an adjacent underlay (10.2), so that the underlays (10.1, 10.2) have a water-tight and water vapour-permeable welded joint.

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