Roofing sheet, roll, roof and method for covering a roof structure using the roofing sheet

Abstract

The invention relates to a roofing sheet (1) for covering a roof structure (91), wherein the roofing sheet (1) comprises a laminate (2) of a solid layer (3) with an elastomer compound and a foam layer (4) with the same elastomer compound, wherein the roofing sheet (1) has an overall mass, wherein the roofing sheet (1) comprises the elastomer compound in a mass fraction of at least eighty percent, preferably at least ninety percent and most preferably at least ninety-five percent to the overall mass. The invention further relates to a roll (8) comprising windings of the roofing sheet (1) and a roof (9) comprising a roof structure (91) and a first roofing sheet (11), corresponding the aforementioned roofing sheet (1), covering said roof structure (91). The invention further relates to a method for covering a roof structure (91) using the first roofing sheet (11).

Description

[0001] Roofing sheet, roll , roof and method for covering a roof structure using the roofing sheet

[0002] BACKGROUND

[0003] The invention relates to a roofing sheet for covering a roof structure , a roll comprising windings of the roofing sheet, a roof comprising a roof structure and a roofing sheet covering said roof structure and a method for covering a roof structure using the roofing sheet .

[0004] A known roofing sheet comprises a laminate of a top layer of solid ethylene propylene diene monomer (EPDM) rubber, a bottom layer of bitumen and an intermediate layer of thermoplastic elastomer ( TPE ) .

[0005] SUMMARY OF THE INVENTION

[0006] A disadvantage of the known roofing sheet is unsuitable for recycling because of the di fferent materials used in the laminate . Moreover, the known roofing sheet has a relatively high mass and / or thickness , thereby limiting the width and / or length of the roofing sheet that can be wound into a roll in view of the maximum weight that can safely be lifted by a single person .

[0007] It is an object of the present invention to provide a roofing sheet , a roll , a roof and a method for covering a roof structure using the roofing sheet , wherein at least one of the aforementioned disadvantages can at least partially be mitigated .

[0008] According to a first aspect , the invention provides a roofing sheet for covering a roof structure, wherein the roofing sheet comprises a laminate of a solid layer with an elastomer compound and a foam layer with the same elastomer compound, wherein the roofing sheet comprises the elastomer compound or the same elastomer compound in a mass fraction of at least eighty percent , preferably at least ninety percent and most preferably at least ninety-five percent to the overall mass .

[0009] Hence, at least two layers of the roofing sheet are made from the same elastomer compound and can be more easily recycled . Moreover, by using a solid layer and a foam, dif ferent material properties can be exploited, while maintaining the recyclability . In particular, the solid layer may be water proof and UV-resistant , and as such can be used as an outermost layer of the laminate , i . e . the layer that is exposed to the sun and weather . Meanwhile , the foam layer can provide thermal isolation, can absorb impacts from above and / or can even out or prevent damages as a result of irregularities from below . In particular, it is no longer necessary to flatten the underlying surface prior to application of the roofing sheet, which can save valuable time . Moreover, the foam layer can reduce the overall weight or mass of the roofing sheet, thus allowing for wider and / or longer lengths of the roofing sheet to be wound into a roll . It is further expected that the laminate of the two layers will remain flexible over a longer period of time , or even permanently . The remaining mass fraction may consist of adhesives used to bond the layers of the laminate .

[0010] In one embodiment the elastomer compound is a polyolefin based thermoplastic compound . Such a thermoplastic compound becomes soft when heated and can be easily applied to a roof in the soft state .

[0011] In another embodiment the elastomer compound is one of : ethylene propylene diene monomer rubber, thermoplastic olefin or thermoplastic elastomer .

[0012] In a preferred embodiment the solid layer and / or the foam layer comprise a mass fraction of at least eighty percent, preferably at least ninety percent and most preferably at least one-hundred percent of the elastomer compound . Hence, the chemical composition of the layers can be more uniform . In other words , no materials other than the elastomer compound are present in signi ficant quantities in the solid layer and / or the foam layer .

[0013] In another embodiment the foam layer has an airfilled, open-celled or closed-celled structure . Such a structure has a relatively low weight or mass , thereby reducing the overall weight of the roofing sheet . Moreover, in the case of closed-celled structures , the thermal isolation and / or flame retardant properties of the foam layer may be further improved . In one embodiment, for example, the foam layer has flame retardant properties . In other words , the foam layer may be fire resistant or fire rated .

[0014] In another embodiment the laminate further comprises a bonding layer with a first adhesive that bonds the foam layer to the solid layer . Hence , the foam layer and the solid layer can be reliably kept together during winding into , storage in and / or unwinding from a roll . Moreover, the foam layer and the solid layer can be reliably kept together during the application of the laminate on a roof structure .

[0015] In another embodiment the solid layer has a first thickness in a range of three tenths of a millimeter to two millimeters . Because the solid layer can be bonded directly to the foam layer, the solid layer can be kept relatively thin .

[0016] In another embodiment the foam layer has a second thickness in a range of three tenths of a millimeter to three millimeters . The thicker the foam layer, the more the foam layer is able to provide the aforementioned characteristics .

[0017] In another embodiment the solid layer has a first density, wherein the foam layer has a second density that is less than seventy percent of the first density, preferably less than sixty percent of the first density and most preferably less than fifty percent of the first density . As mentioned before, the foam layer can reduce the overall weight or mass of the roofing sheet, thus allowing for wider and / or longer lengths of the roofing sheet to be wound into a roll .

[0018] In another embodiment the roofing sheet has an overall mass per unit area of equal to or less than two kilograms per square meter . Hence , when providing the roofing sheet at a length of ten meters and a width of one meter, the overall weight or mass of the roofing sheet can be kept at or below twenty kilograms .

[0019] In another embodiment the roofing sheet has a width of at least one-hundred- and-ten centimeters , preferably at least one-hundred- and-forty centimeters and most preferably at least one-hundred-and-f i fty centimeters . As the weight or mass of the roofing sheet per unit area can be reduced, the width can ef fectively be increased while keeping the overall weight or mass of the roofing sheet the same . When the width of the roofing sheet is increased, more area of the roof structure can be covered using the roofing sheet .

[0020] In another embodiment the roofing sheet has a length of at least eight meters , preferably at least nine meters and most preferably at least ten meters . Hence, a considerable length of the roofing sheet can be laid onto the roof structure in a continuous manner .

[0021] In another embodiment the roofing sheet has a first splicing edge defined by the solid layer and a second splicing edge defined by the foam layer opposite to the first splicing edge, wherein the solid layer extends from the first splicing edge towards the second splicing edge and stops short of said second splicing edge at a first recessed edge that extends parallel to and short of the second splicing edge , wherein the foam layer extends from the second splicing edge towards the first splicing edge and stops short of said first splicing edge at a second recessed edge that extends parallel to and short of the first splicing edge . The recessed edges allow for the solid layer and the foam layer to be arranged at least partially in overlap with a corresponding foam layer and solid layer of an adjacent roofing sheet with the same edge configuration . In particular, a hal f lap splice or hal f lap joint may be formed between adj acent roofing sheets . Because of the overlap, a reliable seal against water ingress can be formed between the adjacent roofing sheets by simply joining the roofing sheets together, thereby improving the waterproofing of the roof structure . Manually applying a further sealing to the opposing edges , although not excluded from the scope of this invention, would not even be necessary .

[0022] Preferably, the first recessed edge is recessed from the second splicing edge over a first splicing distance and wherein the second recessed edge is recessed from the first splicing edge over a second splicing distance that is equal or substantially equal to the first splicing distance . Hence, the first splicing edge can be arranged in abutment with the second recessed edge . Similarly, the second splicing edge can be arranged in abutment with the first recessed edge .

[0023] Additionally or alternatively, the laminate comprises a bonding layer with a first adhesive applied to one or both of the solid layer and the foam layer in a first splicing area between the second recessed edge and the first splicing edge or in a second splicing area between the first recessed edge and the second splicing edge, respectively . By having the first adhesive of the bonding layer pre-applied to at least one of the splicing areas , the roofing sheet can self-adhere to an adj acent roofing sheet .

[0024] Preferably, the roofing sheet further comprises at least one liner that is removably attached to the bonding layer in the first splicing area and / or the second splicing area . The at least one liner may prevent that the windings of the roofing sheet on a roll adhere to each other, or that the roofing sheet prematurely adheres to adjacent roofing sheets and / or the roof structure .

[0025] In another embodiment the foam layer is reinforced . In particular, the laminate comprises fiberglass reinforcements reinforcing the foam layer . The reinforcements ccaann improve the strength and / or the resistance to tearing of the foam layer . In particular, when the foam layer is fastened to the roof structure using mechanical fasteners that pierce through the foam layer, the foam layer can be kept together around the mechanical fasteners .

[0026] According to a second aspect , the invention provides aa roll comprising windings of a roofing sheet according to any one of the embodiment of the first aspect of the invention, wherein the roll has a roll mass of equal to or less than twenty-three kilograms , preferably equal to or less than twenty-two kilograms and most preferably equal to or less than twenty-one kilograms . The roll can thus be safely lifted by a single person, in accordance with health and safety guidelines .

[0027] According to a third aspect , the invention provides a roof comprising a roof structure and a first roofing sheet, corresponding the roofing sheet according to any one of the embodiments of the first aspect of the invention, covering said roof structure .

[0028] The roof includes the roofing sheet according to the first aspect of the invention, and therefore has the same technical advantages , which will not be repeated hereafter .

[0029] In one embodiment of the roof , the first roofing sheet is applied to the roof structure with the foam layer facing towards the roof structure and the solid layer facing away from the roof structure . Hence, the solid layer can be exposed to the sun and weather, and as such shields the foam layer from external influences . Moreover, the foam layer can even out irregularities in the roof structure and at least partially absorb impacts of objects falling onto the solid layer .

[0030] In another embodiment, the roof comprises one or more further roofing sheets , corresponding to the roofing sheet according to any one of the embodiments of the first aspect of the invention, wherein the first roofing sheet and the one or more further roofing sheets are joint using overlapping joints . In particular, a half lap splice or hal f lap joint may be formed between adjacent roofing sheets . Because of the overlap, a reliable seal against water ingress can be formed between the adjacent roofing sheets by simply joining the roofing sheets together, thereby improving the waterproofing of the roof structure .

[0031] Preferably, the roof comprises one or more mechanical fasteners for mechanically fastening the first roofing sheet to the roof structure , wherein the one or more mechanical fasteners are provided in the overlapping joint between the first roofing sheet and an adjacent further roofing sheet of the one or more further roofing sheets . In the overlapping joint, the one or more mechanical fasteners in one of the roofing sheets can be conveniently covered by the overlapping section of an adjacent roofing sheet , thereby effectively hiding the one or more mechanical fasteners from view and / or ef fectively sealing the location of the one or more mechanical fasteners against water ingress .

[0032] According to a fourth aspect , the invention provides a method for covering a roof structure using a first roofing sheet , corresponding to the roofing sheet according to any one of the embodiments of the first aspect of the invention, wherein the method comprises the step of : applying the first roofing sheet to the roof structure in an orientation in which the foam layer is between the roof structure and the solid layer .

[0033] In the orientation as specified above, the solid layer can be exposed to the sun and weather, and as such shields the foam layer from external influences . Moreover, the foam layer can even out irregularities in the roof structure and at least partially absorb impacts of objects falling onto the solid layer . The method further relates to the practical implementation of the roofing sheet according to the first aspect of the invention on a roof structure , and therefore has the same technical advantages , which will not be repeated hereafter .

[0034] In one embodiment the method further comprises the steps of : applying one or more further roofing sheets , corresponding to the roofing sheet according to any one of the embodiments of the first aspect of the invention, to the roof structure ; and the first roofing sheet and the one or more further roofing sheets using overlapping joints . In particular, a hal f lap splice or half lap joint may be formed between adjacent roofing sheets . Because of the overlap, a reliable seal against water ingress can be formed between the adjacent roofing sheets by simply joining the roofing sheets together, thereby improving the waterproofing of the roof structure .

[0035] In another embodiment the foam layer of the first roofing sheet is applied directly to the roof structure . In other words , no further layers are used to apply the foam layer to the roof structure .

[0036] The method further comprises the step of bonding the laminate of the first roofing sheet to the roof structure using a second adhesive . In other words , no further layers are used to apply the foam layer to the roof structure . In the context of the present invention, the second adhesive is not considered to form a layer, as it is the medium that creates the direct bonding of the foam layer to the roof structure .

[0037] Preferably, the method comprises the step of : applying the second adhesive intermittently or continuously between the laminate of the first roofing sheet and the roof structure . The intermittent application of the second adhesive may reduce the amount of second adhesive required . The roof may be provided with ballast to keep the first roofing sheet on the roof structure .

[0038] In another embodiment the method further comprises the step of : mechanically fastening the first roofing sheet to the roof structure using one or more mechanical fasteners . The mechanical fastening can improve the bonding of the first roofing sheet to the roofing structure .

[0039] In another embodiment each roofing sheet has a first splicing edge defined by the solid layer and a second splicing edge defined by the foam layer opposite to the first splicing edge, wherein the solid layer extends from the first splicing edge towards the second splicing edge and stops short of said second splicing edge at a first recessed edge that extends parallel to and short of the second splicing edge , wherein the foam layer extends from the second splicing edge towards the first splicing edge and stops short of said first splicing edge at a second recessed edge that extends parallel to and short of the first splicing edge, wherein the method comprises the steps of : mechanically fastening the foam layer of the first roofing sheet to the roof structure between the first recessed edge and the second splicing edge using one or more mechanical fasteners ; and covering the one or more mechanical fasteners in the foam layer of the first roofing sheet with the solid layer of an adjacent further roofing sheet of the one or more further roofing sheets . In this manner, the one or more mechanical fasteners can effectively be hidden from view . Moreover, the solid layer can ef fectively seal the location of the one or more mechanical fasteners in the foam layer against water ingress .

[0040] According to a fifth, unclaimed aspect, the invention provides a roofing sheet for covering a roof structure, wherein the roofing sheet comprises a laminate of a solid layer with an elastomer compound and a foam layer with the same elastomer compound . The roofing sheet according to the fi fth unclaimed aspect may be combined with any of the features mentioned in the embodiments related to the first aspect of the invention .

[0041] The various aspects and features described and shown in the specification can be applied, individually, wherever possible . These individual aspects , in particular the aspects and features described in the attached dependent claims , can be made subj ect of divisional patent applications .

[0042] BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The invention will be elucidated on the basis of an exemplary embodiment shown in the attached schematic drawings , in which : figure 1 shows an isometric view of a first roofing sheet according to the present invention, partially unwound from a roll ; figure 2 shows a cross section of the first roofing sheet according to the line I I-I I in figure 1 ; figures 3 and 4 show isometric views of the steps of forming an overlapping joint between the first roofing sheet of figure 1 and a further roofing sheet ; figure 5 shows a cross section of the overlapping joint between the first roofing sheet and the further roofing sheet according to the line V-V in figure 4 ; figure 6 shows a cross section of the first roofing sheet of figure 1 during impact of a sharp object ; and figure 7 shows an isometric view of a building with a roof having a roof structure that is covered by the first roofing sheet of figure 1 and a plurality of further roofing sheets . DETAILED DESCRIPTION OF THE INVENTION

[0044] Figure 1 shows a roof membrane, a roofing membrane , a roof sheet or a roofing sheet 1 according to the invention . The roofing sheet 1 is coiled or wound up about a shaft to form a roll 8 .

[0045] Figure 7 further shows a building with a roof 9 . The roof 9 comprises a roof structure 91 and a plurality of roofing sheets 11-14 , corresponding to the roofing sheet 1 of figure 1 , covering said roof structure 91 .

[0046] Although the roofing sheet 1 is described throughout the specification as a 'roofing sheet ' , it may be appreciated that the sheet may also be used for covering other surfaces than a roof , for example a wall or a basement , which is also considered within the scope of this invention .

[0047] As shown in figure 1 , the roofing sheet 1 has a width W and a length L . In this example, the width W is wider than one-hundred centimeters . In particular, the width W is approximately one-hundred-and-forty centimeters . The length L is approximately ten meters . It will be appreciated that other widths W and lengths L are also within the scope of the invention . Note that in figure 1 , the roofing sheet 1 is coiled up over several windings into the roll 8 .

[0048] As best seen in figure 2 , the roofing sheet 1 comprises a laminate 2 of a solid layer 3 with a specific rubber material or elastomer compound, in particular a polyolefin based thermoplastic compound, more in particular ethylene propylene diene monomer (EPDM) rubber, thermoplastic olefin ( TPO) or thermoplastic elastomer ( TPE ) , and a sponge or foam layer 4 with the same specific rubber material or elastomer compound, in particular a polyolefin based thermoplastic compound, more in particular ethylene propylene diene monomer (EPDM) rubber, thermoplastic olefin ( TPO) or thermoplastic elastomer ( TPE ) . The laminate may be formed in a manufacturing process involving a step of co-extrusion, i . e . process in which the solid layer 3 and the foam layer 4 are extruded simultaneously .

[0049] In particular, the solid layer 3 comprises a high density, non-porous and / or non-breathing rubber material . Specifically, the solid layer 3 has a first density that is at least one-thousand- three-hundred milligram per cubic centimeter, and preferably at least one-thousand-f our- hundred milligram per cubic centimeter .

[0050] The solid layer 3 has a first thickness T1 of approximately two millimeters . Alternatively, the first thickness T1 may be reduced, depending on the required specification of the roofing sheet 1 , to less than a millimeter, or even only a few tenths of a millimeter .

[0051] The solid layer 3 may be black or white , or at request may be provided in other colors as well .

[0052] The foam layer 4 is more porous or more breathable than the solid layer 3 . In particular, the foam layer 4 has a second density that is less than seventy percent of the first density . Speci fically, the foam layer 4 has a first density of less than one-thousand milligram per cubic centimeter, and preferably less than equal to or less than eight-hundred milligram per cubic centimeter .

[0053] Moreover, the foam layer 4 has a cellular, sponge-like , expanded, air- filled, open-celled, closed- celled or bubble-like structure . The foam layer 4 is formed by introducing a foaming agent during manufacture .

[0054] The foam layer 4 has a second thickness T2 of approximately three millimeters . Alternatively, the second thickness T2 may be reduced, depending on the required specification of the roofing sheet 1 , to less than a millimeter, or even only a few tenths of a millimeter . In particular, the second thickness T2 may be equal or substantially equal to the first thickness T1 .

[0055] As schematically shown in figure 1 , the foam layer 4 may optionally be reinforced, for example using fiberglass reinforcements 7 . Note that, although the reinforcements 7 have been shown only locally in the foam layer 4 in figure 1 , they may be provided across the entire surface area of the foam layer 4 .

[0056] In this example , the solid layer 3 and the foam layer 4 are made entirely out of ethylene propylene diene monomer rubber, thermoplastic olefin or thermoplastic elastomer . In other words , no materials other than ethylene propylene diene monomer rubber, alternatively thermoplastic olefin or thermoplastic elastomer are present in significant quantities in the solid layer 3 and the foam layer 4 . Hence, the chemical composition of the layers 3 , 4 is relatively uniform.

[0057] As further shown in figure 2 , the roofing sheet 1 has a first longitudinal edge, a first joining edge or a first splicing edge S1 defined by the solid layer 3 . The roofing sheet 1 has a second longitudinal edge, a second joining edge or a second splicing edge S2 defined by the foam layer 4 opposite to the first splicing edge S1 . The first splicing edge S1 and the second splicing edge S2 are mutually parallel . In this example, the first splicing edge S1 and the second splicing edge S2 form the outer longitudinal edges of the roofing sheet 1 .

[0058] Moreover, in this example , the solid layer 3 extends from the first splicing edge S1 towards the second splicing edge S2 and stops or terminates short of said second splicing edge S2 at a first recessed edge R1 . The first recessed edge R1 extends parallel or substantially parallel to the second splicing edge S2 . Moreover, in this example, the foam layer 4 extends from the second splicing edge S2 towards the first splicing edge S1 and stops or terminates short of said first splicing edge S1 at a second recessed edge R2 . The second recessed edge R2 extends parallel or substantially parallel to the first splicing edge S 1 .

[0059] In the context of the present invention, the term ' short of ' should be interpreted as the respective layers 3 , 4 extending towards or in the direction of , but not reaching and / or remaining spaced apart from the respective splicing edge S1 , S2 .

[0060] As shown in figure 2 , the first recessed edge R1 is recessed from the second splicing edge S2 over a first joining distance or a first splicing distance D1 . In other words , the foam layer 4 projects beyond and / or overlaps the solid layer 3 at the first recessed edge R1 over the first splicing distance D1 . Similarly, the second recessed edge R2 is recessed from the first splicing edge S 1 over a second joining distance or a second splicing distance D2 . In other words , the solid layer 3 projects beyond and / or overlaps the foam layer 4 at the second recessed edge R2 over the second splicing distance D2 .

[0061] In this example, the second splicing distance D2 is equal or substantially equal to the first splicing distance D1 .

[0062] The part of the solid layer 3 overlapping the foam layer 4 forms or defines a first joining area or a first splicing area A1 . Specifically, the first splicing area Al extends between the second recessed edge R2 and the first splicing edge S1 . Similarly, the part of the foam layer 4 overlapping the solid layer 3 forms or defines a second joining area or a second splicing area A2 . Specifically, the second splicing area A2 extends between the first recessed edge R1 and the second splicing edge S2 .

[0063] As best seen in figure 2 , the laminate 2 further comprises a bonding layer 5 that adheres , glues or bonds the foam layer 4 to the solid layer 3 . The bonding layer 5 extends between the solid layer 3 and the foam layer 4 . The bonding layer 5 comprises or consists of a first glue or first adhesive . In this example, the bonding layer 5 comprises or consist of a thermoplastic adhesive, in particular a hot-melt adhesive .

[0064] In this example, the bonding layer 5 extends along and / or is applied to the solid layer 3 in the first splicing area Al . Hence , at least a part of the bonding layer 5 is exposed in said first splicing area A1 . Hence , as shown in figure 4 , the first adhesive in said bonding layer 5 can self-adhere to the foam layer 4 of an adj acent further roofing sheet 12 .

[0065] As shown in figure 2 , the roofing sheet 1 further comprises a liner 6 that is removably attached to the bonding layer 5 in the first splicing area A1 .

[0066] Additionally or alternatively, the bonding layer 5 may extend along and / or may be applied to the foam layer 4 in the second splicing area A2 , and optionally a further liner (not shown) may be attached to the bonding layer 5 in said second splicing area A2 .

[0067] In yet a further alternative embodiment (not shown) , the roofing sheet may be provided with a fully overlapping solid layer 3 and foam layer 4 , i . e . without the recessed edges R1 , R2 and / or the splicing areas A1 , A2 .

[0068] The previously discussed roofing sheet 1 , at a width W of more than one-hundred centimeters , has an overall mass per unit area of equal to or less than two kilograms per square meter . In particular, the roll 8 , at a width W of more than one-hundred centimeters and a length of ten meters , has a roll mass of less than twenty-three kilograms . Hence , the roll 8 can be safely li fted by a single person in accordance with health and safety guidelines in most countries .

[0069] Moreover, the roofing sheet 1 according to the present invention comprises the same elastomer compound, in this example ethylene propylene diene monomer rubber, in a mass fraction of at least ninety-five percent to the overall mass . In other words , the solid layer 3 and the foam layer 4 account for almost the entire mass of the roofing sheet 1 . The remaining mass fraction may be attributed to the bonding layer 5, the liner 6 and / or the reinforcements 7 .

[0070] A method for covering the roof structure 91 of a roof 9 , as shown in figure 7 , using a plurality of roofing sheets 11-14 , corresponding to the previously discussed roofing sheet 1 , will now be briefly elucidated with reference to figures 1- 6 .

[0071] Figure 1 shows the situation in which the roofing sheet 1 is supplied as a roll 8 . The roofing sheet 1 has been partially unwound from the roll 8 .

[0072] Figure 3 shows the situation in which a first roofing sheet 11 , corresponding to the roofing sheet 1 as shown in figure 1 , and a further roofing sheet 12 , corresponding to the roofing sheet 1 as shown in figure 1 , are placed adj acent to each other for joining or splicing . In particular, the liner 6 of the first roofing sheet 11 is being manually removed from the solid layer 3 in the first splicing area A2 to expose the first adhesive of the bonding layer 5.

[0073] Figure 4 shows the situation in which solid layer 3 in the first splicing area A1 of the first roofing sheet

[0074] 11 is moved in a partially overlapping position over the foam layer 4 in the second splicing area A2 of the further roofing sheet 12 . The first adhesive of the bonding layer 5 in the first splicing area A1 of the first roofing sheet 11 sel f-adheres to the foam layer 4 in the second splicing area A2 of the further roofing sheet 12 , thereby bonding the layers 3 , 4 of the pair of adj acent roofing sheets 11 ,

[0075] 12 to each other .

[0076] In this manner, an lap splice, an half lap splice , an overlapping splice, a lap joint, a half lap joint, an overlapping joint J1 can be formed between the pair of adjacent roofing sheets 11 , 12 . In the context of the present invention, the term 'half ' in 'hal f lap splice' or 'half lap joint' should not be interpreted literally as a splice or joint that is formed by joining the two roofing sheets 11 , 12 at half thickness . Instead, 'hal f lap splice' or a 'half lap joint ' is to be interpreted as a splice or joint where the pair of adj acent roofing sheets 11 , 12 have a reduced thickness to allow for splicing or joining within the overall thickness the respective roofing sheets 11 , 12 . Hence, a joint or splice may be formed without adding thickness at the joint or splice .

[0077] As shown in figures 5 and 7 , the first roofing sheets 11- 14 are applied to the roof structure 91 in an orientation in which the foam layer 4 is between the roof structure 91 and the solid layer 3 . In other words , the solid layer 3 is at a side of the laminate 2 facing upwards and / or away from the roof structure 91 and the foam layer 4 is at a side of the laminate 2 facing downwards and / or towards the roof structure 91 . In this example, the solid layer 3 is the top or outermost layer of the laminate 2 . The foam layer 4 is the lower or innermost layer of the laminate 2 .

[0078] The laminate 2 of the roofing sheets 11-14 is bounded to the roof structure 91 using a second adhesive . This second adhesive may be pre-applied to the foam layer 4 or applied in-situ . The second adhesive may be applied intermittently, i . e . according to a pattern, to achieve a partial bonding, or continuously, to achieve a full bonding . Alternatively, the roofing sheets 11-14 may be applied to the roof structure 91 without a second adhesive . In such a case, the roof 9 may be provided with ballast (not shown) to keep the roofing sheets 11-14 down on the roof structure 91 .

[0079] Figure 5 further shows that, optionally, the first roofing sheet 11 may be mechanically fixed or fastened to the roof structure 91 using one or more mechanical fasteners 92 , for example a screw connection . In particular, the first roofing sheet 11 can be mechanically fastened to the roof structure 91 at the foam layer 4 in the second splicing area A2 . This second splicing area A2 and any of the mechanical fasteners 92 contained therein can conveniently be covered with the solid layer 3 of the adjacent further roofing sheet 12 , thereby hiding the mechanical fasteners 92 from view and ensuring a waterproof sealing of said second splicing area A2 around said mechanical fasteners 92 .

[0080] Figure 6 shows the situation in which a sharp object 100 falls onto the roofing sheet 1 from above . Note that the impact can be at least partially absorbed by the foam layer 4 , which is compressible, thereby preventing that the sharp object 100 pierces , penetrates or damages the solid layer 3 and / or the foam layer 4 .

[0081] Figure 7 shows the building with the roof 9 after application of the plurality of roofing sheets 11-14 . Note that each pair of adj acent lengths of the roofing sheets 11- 14 is joined or spliced using overlapping splices or overlapping joints J1-J4 similar to the overlapping joint J1 as previously described .

[0082] It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention . From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the scope of the present invention .

[0083] LIST OF REFERENCE NUMERALS

[0084] 1 roofing sheet

[0085] 11 first roofing sheet

[0086] 12- 14 further roofing sheets

[0087] 2 laminate

[0088] 3 solid layer

[0089] 4 foam layer

[0090] 5 bonding layer

[0091] 6 liner

[0092] 7 reinforcements

[0093] 8 roll

[0094] 9 roof

[0095] 91 roof structure

[0096] 92 fastener

[0097] 100 sharp object

[0098] A1 first splicing area

[0099] A2 second splicing area D1 first splicing distance

[0100] D2 second splicing distance

[0101] J1-J4 overlapping joints

[0102] L length R1 first recessed edge

[0103] R2 second recessed edge

[0104] S1 first splicing edge

[0105] S2 second splicing edge

[0106] T1 first thickness T2 second thickness

[0107] W width

Claims

AMENDED CLAIMS received by the International Bureau on 11 August 2025 (11.08.2025)1. Roofing sheet (1) for covering a roof structure (91) , wherein the roofing sheet (1) comprises a laminate (2) of a solid layer (3) with ethylene propylene diene monomer rubber aanndd aa foam layer (4) with ethylene propylene diene monomer rubber, wherein the roofing sheet(1) has an overall mass, wherein the roofing sheet (1) comprises ethylene propylene diene monomer rubber in a mass fraction of at least eighty percent, preferably at least ninety percent and most preferably at least ninety-five percent to the overall mass.2 . Roofing sheet (1) according to claim 1, wherein the solid layer (3) and / or the foam layer (4) comprise aa mass fraction of at least eighty percent, preferably at least ninety percent and most preferably at least one-hundred percent of ethylene propylene diene monomer rubber .

3. Roofing sheet (1) according to claim 1 or 2, wherein the foam layer (4) has an air-filled, open-celled or closed-celled structure.4 . Roofing sheet (1) according to any one of the preceding claims, wherein the foam layer (4) has flame retardant properties .5 . Roofing sheet (1) according to any one of the preceding claims, wherein the laminate (2) further comprises a bonding layer (5) with a first adhesive that bonds the foam layer (4) to the solid layer (3) .

6. Roofing sheet (1) according to any one of the preceding claims, wherein the solid layer (3) has a first thickness (T1) in a range of three tenths of a millimeter to two millimeters .7 . Roofing sheet (1) according to any one of the preceding claims, wherein the foam layer (4) has a second thickness (T2) in a range of three tenths of a millimeterto three millimeters .8 . Roofing sheet (1) according to any one of the preceding claims, wherein the solid layer (3) has a first density, wherein the foam layer (4) has aa second density that is lleessss than seventy percent of the first density, preferably less than sixty percent of the first density and most preferably less than fifty percent of the first density.

9. Roofing sheet (1) according to any one of the preceding claims, wherein the roofing sheet (1) has an overall mass per unit area of equal to oorr less than two kilograms per square meter.

10. Roofing sheet (1) according to any one of the preceding claims, wherein the roofing sheet (1) has a width(W) of at least one-hundred-and-ten centimeters, preferably at least one-hundred-and-f orty centimeters and most preferably at least one-hundred-and-f ifty centimeters.

11. Roofing sheet (1) according to any one of the preceding claims, wherein the roofing sheet (1) has a length (L) of at least eight meters, preferably at least nine meters and most preferably at least ten meters .

12. Roofing sheet (1) according to any one of the preceding claims, wherein the roofing sheet (1) has a first splicing edge (S1) defined by the solid layer (3) and a second splicing edge (S2) defined by the foam layer (4) opposite to the first splicing edge (S1), wherein the solid layer (3) extends from the first splicing edge (S1) towards the second splicing edge (S2) and stops short of said second splicing edge (S2) at a first recessed edge (Rl) that extends parallel to and short of the second splicing edge (S2), wherein the foam layer (4) extends from the second splicing edge (S2) towards the first splicing edge(S1) and stops short of said first splicing edge (S1) at a second recessed edge (R2) that extends parallel to and short of the first splicing edge (S1) .

13. Roofing sheet (1) according to claim 12,wherein the first recessed edge (R1) is recessed from the second splicing edge (S2) over a first splicing distance (D1) and wherein the second recessed edge (R2) is recessed from the first splicing edge (S1) over aa second splicing distance (D2) that is equal or substantially equal to the first splicing distance (D1) .

14. Roofing sheet (1) according to claim 12 or13, wherein the laminate (2) comprises a bonding layer (5) with a first adhesive applied to one or both of the solid layer (3) and the foam layer (4) in a first splicing area (A1) between the second recessed edge (R2) and the first splicing edge (S1) or in aa second splicing area (A2) between the first recessed edge (Rl) and the second splicing edge (S2), respectively.

15. Roofing sheet (1) according to claim 14, wherein the roofing sheet (1) further comprises at least one liner (6) that is removably attached to the bonding layer (5) in the first splicing area (Al) and / or the second splicing area (A2) .

16. Roofing sheet (1) according to any one of the preceding claims, wherein the foam layer (4) is reinforced.

17. Roofing sheet (1) according to claim 16, wherein the laminate (2) comprises fiberglass reinforcements (7) reinforcing the foam layer (4) .

18. Roll (8) comprising windings of a roofing sheet (1) according to any one of the preceding claims, wherein the roll (8) has a roll mass of equal to or less than twenty-three kilograms, preferably equal to or less than twenty-two kilograms and most preferably equal to or less than twenty-one kilograms .

19. Roof (9) comprising a roof structure (91) and a first roofing sheet (11), corresponding the roofing sheet(1) according to any one of claims 1-21, covering said roof structure ( 91 ) .

20. Roof (9) according to claim 19, wherein the first roofing sheet (11) is applied to the roof structure(91) with the foam layer (4) facing towards the roof structure (91) and the solid layer (3) facing away from the roof structure (91) .

21. Roof (9) according to claim 19 or 20, wherein the roof (9) comprises one or more further roofing sheets(12-14) , corresponding to the roofing sheet (1) according to any one of claims 1-18, wherein the first roofing sheet (11) and the one or more further roofing sheets (12-14) are joint using overlapping joints (J1-J4) .

22. Roof (9) according to claim 21, wherein the roof (9) comprises oonnee or more mechanical fasteners (92) for mechanically fastening the first roofing sheet (11) to the roof structure (91), wherein the one or more mechanical fasteners (92) aarree provided in the overlapping joint (J1) between the first roofing sheet (11) and aann adjacent further roofing sheet (12) of the one or more further roofing sheets (12-14) .

23. Method for covering a roof structure (91) using aa first roofing sheet ( 11 ) , corresponding the roofing sheet (1) according to any one of claims 1-22, wherein the method comprises the step of : applying the first roofing sheet (11) to the roof structure (91) in aann orientation in which the foam layer (4) is between the roof structure (91) and the solid layer ( 3 ) .

24. Method according to claim 23, wherein the method further comprises the steps of : applying one or more further roofing sheets(12-14) , corresponding to the roofing sheet (1) according to any one of claims 1-21, to the roof structure (91); and joining the first roofing sheet (11) and the one or more further roofing sshheeeettss (12-14) using overlapping joints (J1-J4) .

25. Method according to claim 23 or 24, wherein the foam layer (4) of the first roofing sheet (11) is applied directly to the roof structure (91) .

26. Method according to any one of claims 23-25, wherein the method further comprises the step of : bonding the laminate (2) of the first roofing sheet (11) to the roof structure (91) using a second adhesive .

27. Method according to claim 26, wherein the method comprises the step of : applying the second adhesive intermittently or continuously between the laminate (2) of the first roofing sheet (11) and the roof structure (91) .

28. Method according to any one of claims 23-27, wherein the method further comprises the step of : mechanically fastening the first roofing sheet (11) to the roof structure (91) using one or more mechanical fasteners (92) .

29. Method according to claim 24, wherein each roofing sheet (11-14) has a first splicing edge (S1) defined by the solid layer (3) and a second splicing edge(S2) defined by the foam layer (4) opposite to the first splicing edge (S1) , wherein the solid layer (3) extends from the first splicing edge (S1) towards the second splicing edge (S2) and stops short of said second splicing edge (S2) at a first recessed edge (R1) that extends parallel to and short of the second splicing edge (S2) , wherein the foam layer (4) extends from the second splicing edge (S2) towards the first splicing edge (S1) and stops short of said first splicing edge (S1) at a second recessed edge (R2) that extends parallel to and short of the first splicing edge (S1) , wherein the method comprises the steps of : mechanically fastening the foam layer (4) of the first roofing sheet (11) to the roof structure (91) between the first recessed edge (R1) and the second splicing edge (S2) using one or more mechanical fasteners(92); and covering the one or more mechanical fasteners(92) in the foam layer (4) of the first roofing sheet (11) with the solid layer (3) of aann adjacent further roofing sheet (12) of the one or more further roofing sheets (12-14) .

Images