A non-porous and hydrophobic roofing element, and the roof of a building comprising such a roofing element

A non-porous, hydrophobic roofing element with unordered reliefs and chamfers addresses the issues of natural slate tiles by preventing capillary rise and leaks, enhancing waterproofing and reducing material usage.

FR3140639B1Active Publication Date: 2024-12-13MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
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Patent Information

Application Number
FR2022010316
Authority / Receiving Office
FR · FR
Patent Type
Patents
Current Assignee / Owner
Filing Date
2022-10-07
Publication Date
2024-12-13
Estimated Expiration
2042-10-07

AI Technical Summary

Technical Problem

Natural slate tiles are heavy, fragile, and porous, leading to issues like capillary rise of rainwater, leaks, and environmental impact, while synthetic tiles with transverse grooves fail to effectively drain fluids and promote leaks.

Method used

A non-porous, hydrophobic roofing element with unordered reliefs and chamfers, made from thermoplastic materials, which repels water and promotes fluid drainage, reducing coverage rates and environmental impact.

Benefits of technology

The solution effectively prevents capillary rise and leaks, enhances waterproofing, reduces material usage, and extends the lifespan of the roof by improving fluid evacuation and preventing vegetation growth.

✦ Generated by Eureka AI based on patent content.

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Abstract

A roofing element (10), particularly intended to cover the framework of a building, comprising an outer surface (12) extending along a plane (XY) of extension and an inner surface (14) opposite the outer surface (12), the roofing element (10) being delimited by two longitudinal sides (10a, 10b) and two transverse sides (10c, 10d), said sides (10a, 10b, 10c, 10d) defining a closed peripheral contour. The roofing element is made of non-porous and hydrophobic materials, and the outer surface (12) comprises a plurality of reliefs (16) extending in a non-ordered manner within the plane of extension (XY) of the outer surface (12). Figure for the abbreviation: Fig 3
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Description

Title of the invention: Non-porous and hydrophobic roofing element, and roof of a construction comprising such a roofing element

[0001] The present invention relates to the field of covering or roofing elements intended for the production of construction roofs.

[0002] More particularly, the invention relates to a roofing element made of synthetic material.

[0003] By “synthetic” material is meant a material not present in its natural state in the external environment.

[0004] In the construction of structures, especially buildings, the roof of the structure must be capable of not only protecting the interior of the structure from the external environment, but also providing a desired aesthetic appearance.

[0005] Many different roofing materials have been employed to achieve these objectives, such as asphalt shingles, wood shingles, ceramic tiles, slate tiles, fiber cement tiles, etc.

[0006] We know in particular of so-called "natural" slate tiles cut from a schist rock that can be easily separated into plates used in particular for covering buildings.

[0007] Natural slate tiles are generally cut into a substantially rectangular shape and are arranged on battens fixed next to each other on rafters. The battens together form a continuous floor configured to support roof covering elements, in particular slates.

[0008] Slate tiles can also be laid on a batten such as a discontinuous support of pieces of wood onto which hooks are fixed.

[0009] However, such natural slate tiles are relatively heavy, require substantial frameworks and are fragile. Indeed, they can be damaged during storage, transport, or even when fixed to the boarding, or during an impact with an external element, for example hail.

[0010] Furthermore, natural slate tiles are porous and become brittle over time.

[0011] Finally, it is common for rainwater to rise by capillarity to their surface, up to the covering area and can generate leaks via the fixing hook which generates infiltrations in the roof and causes damage to the construction.

[0012] In order to overcome these drawbacks, the standards for laying slate tiles require significant overlaps depending on the slope of the roof.

[0013] Roofing elements made from synthetic materials are also known which have been developed to improve waterproofing compared to natural materials, while retaining the desired aesthetic appearance of these natural materials.

[0014] Reference may be made in this regard to document FR 2 724 961 which describes an artificial slate which is lighter and easier to implement and comprises transverse grooves, perpendicular to the direction of fluid flow and distributed over the upper surface of the slate in order to avoid rising damp phenomena.

[0015] However, such transverse grooves generate an exclusively lateral flow of rainwater, which can cause rainwater to spill between two slate covering areas and thus generate a leak in the roof. In addition, the number of transverse grooves does not allow all the fluids present in the covering area to be drained.

[0016] Furthermore, the known roofing elements have other shortcomings, particularly in terms of the evacuation of fluids or particles present between two superimposed roofing elements.

[0017] Indeed, the rising of fluids by capillarity and the stagnant humidity between the natural or fiber cement slates impose significant rates of coverage between slates.

[0018] Thus, there is a need to improve roofing elements formed from a synthetic material.

[0019] The objective of the invention is to improve the evacuation of fluids or to avoid the retention of fluids which could promote the concentration of particles, or even the development of vegetation between two superimposed roof elements.

[0020] Another objective is to reduce the environmental impact linked to the manufacture of roofing elements, while facilitating the installation of said roofing elements.

[0021] The present invention relates to a roofing or covering element, in particular intended to cover a framework of a construction, and comprising an exterior surface extending along an extension plane and an interior surface opposite the exterior surface.

[0022] The interior surface is advantageously intended to come to bear on the framework of the construction.

[0023] The roofing element is delimited by two longitudinal sides or edges and two transverse sides or edges, said sides delimiting a closed peripheral contour of said roofing element.

[0024] The roofing element is made of non-porous and hydrophobic materials.

[0025] At least the outer surface of the roofing element comprises a plurality of reliefs extending in an unordered manner within the extension plane of the outer surface.

[0026] The plurality of reliefs characterizes the surface roughness of the exterior surface of the roofing element.

[0027] By “unordered” distribution, we mean that these reliefs are distributed on the exterior surface in an aperiodic manner.

[0028] The plurality of reliefs may include grooves or furrows, and projections.

[0029] For example, the reliefs may be regularly or irregularly spaced from each other over the entire exterior surface of the roofing element.

[0030] The plurality of reliefs extend multidirectionally in the plane of the outer surface.

[0031] The reliefs can form straight and / or curved profiles.

[0032] The reliefs may have different shapes and / or different heights and depths. different.

[0033] The roofing element made of non-porous and hydrophobic material has the advantage of eliminating the problem of fluid movement by capillarity known in natural slates and from fiber cement.

[0034] By "hydrophobic" is meant a material which tends to repel water molecules, that is to say that water does not penetrate inside the material and remains on its surface mainly in the form of droplets of generally spherical shape. For example, the contact angle of the droplets on the surface of a hydrophobic material is greater than 90°.

[0035] By "non-porous" is meant a material having a closed structure comprising pores which are not connected to each other and are inaccessible to water and air. In other words, a so-called "non-porous" material is impermeable to external molecules, that is to say that external molecules do not penetrate inside the material.

[0036] The pore size of a non-porous material is less than 100 nanometers, preferably less than 80 nanometers.

[0037] Furthermore, thanks to such a roofing element, it is thus possible to considerably reduce the overlap rates between roofing elements, which makes it possible to reduce the mass per square meter of the roofing elements on the roof.

[0038] Furthermore, such roofing elements can be easily installed on low-slope roofs with the same coverage rate as a roof with a steeper slope.

[0039] We can refer to the table illustrated in [Fig.7] which shows the current recovery rates in relation to the slope of the roof and the geographical area in which the roof is located.

[0040] As illustrated, the table comprises three main columns, namely a first main column grouping data from a known synthetic tile, a second main column grouping data from a roofing element according to the invention, and a third main column grouping data concerning the reduction in the overlap rate between the known synthetic tile and the roofing element according to the invention.

[0041] Each main column includes three sub-columns defining three geographic areas.

[0042] The first geographical zone Zone 1 corresponds to a geographical zone located at an altitude lower than 200m, at a distance greater than 20km from the coast.

[0043] The second geographical zone Zone 2 includes the geographical zones located at an altitude between 200m and 500m and the geographical zones on the coast of the Atlantic coast.

[0044] The third geographical zone Zone 3 includes the geographical zones located at an altitude of between 500m and 900m and the geographical zones on the coast of the English Channel, the North Sea, and the Mediterranean Sea.

[0045] It can be seen that the roofing element according to the invention makes it possible to considerably reduce the overlap rate between superimposed roofing elements, which makes it possible to reduce the total mass of the roof.

[0046] For example, in the first geographical zone Zone 1, taking a roof slope of between 45% and 49%, a known synthetic tile must have an overlap of 120mm, while a roof element according to the invention has an overlap of 60mm, i.e. a reduction in the overlap of 50%. The area of ​​the Z2 gauge, illustrated in Figures 2 and 6, i.e. the area of ​​a roof element not covered by one or more superimposed roof elements, is thus greatly increased. The number of roof elements per square meter can therefore be reduced by 20% in the case of a roof having a slope of between 45% and 49%.

[0047] Finally, the multidirectional surface roughness promotes the flow of fluids between two superimposed roof elements.

[0048] The surface roughness thus makes it possible to drain fluids which infiltrate into the false eaves, that is to say into the central part of a first roof element which is covered by a second upper roof element.

[0049] In addition, the surface roughness makes it possible to avoid the suction phenomena observed between hydrophobic roof elements having smooth external surfaces, to improve the evacuation of fluids and to avoid the retention of fluids which can promote the concentration of particles, or even the development of vegetation between two superimposed roof elements. Thus, the service life of the roof elements and the waterproofing of the roof are increased.

[0050] Furthermore, the hydrophobicity of the roofing element prevents fluids from rising towards the upper part of the roof by capillarity.

[0051] Advantageously, the plurality of reliefs has a variation in thickness around the plane of extension of the outer surface of between 0.1 mm and 2 mm, preferably between 0.1 mm and 0.5 mm.

[0052] In other words, the variation in thickness of the plurality of reliefs corresponds to the maximum distance between the projections and the hollows characterizing the surface roughness.

[0053] According to one embodiment, the interior surface of the roofing element is smooth.

[0054] According to another embodiment, the interior surface of the roofing element comprises a plurality of reliefs extending in a non-ordered manner in the plane of the interior surface of the roofing element.

[0055] In this embodiment, the plurality of reliefs of the inner surface has a variation in thickness around the plane of the inner surface of between 0.1 mm and 2 mm, preferably between 0.1 mm and 0.5 mm.

[0056] According to one embodiment, at least each of the longitudinal sides or edges comprises a thickness reduction or a chamfer connecting to the outer surface and defined by a length and an end thickness.

[0057] The chamfers make it possible to avoid the concentration and coalescence of drops on the lower edge of the roofing element and thus to avoid the concentration of dust, as well as the development of plants. Indeed, the flow of fluid is directed from the upper transverse edge of the roofing element towards the lower transverse edge of the roofing element, which makes it possible to avoid the concentration of fluids on the lower transverse edge.

[0058] Furthermore, the absence of fluid between the roofing elements or on the edge of said roofing elements makes it possible to avoid the development of plants which could cause the roofing elements to move apart and jeopardize the waterproofing of the roof.

[0059] The chamfers thus further improve the lifespan of the roofing elements and the waterproofing of the roof.

[0060] Advantageously, the length defining the chamfer is equal to the distance measured between the start of the variation in thickness of the reliefs and a longitudinal side of the roofing element, said distance being between 1mm and 15mm, preferably between 2mm and 10mm.

[0061] Advantageously, the end thickness is equal to the thickness of the longitudinal side of the roofing element and depends on the thickness of the roofing element.

[0062] For example, the end thickness is between 0.5mm and the thickness of the roofing element minus 0.5mm, preferably between 1mm and half the thickness of the roofing element.

[0063] According to another embodiment, the sides or transverse edges of the roofing element each comprise a reduction in thickness or a chamfer connecting to the outer surface and defined by the end length and thickness.

[0064] In other words, all four sides of the roofing element include a reduction in thickness or chamfer.

[0065] Advantageously, each of the chamfers is flat and extends obliquely from a longitudinal edge towards the outer surface of the roofing element.

[0066] The chamfers prevent the concentration and coalescence of drops on the lower edge of the roofing element and thus prevent the concentration of dust, as well as the growth of plants.

[0067] For example, the roofing element is made from a plastic material, in particular thermoplastic, for example a polyolefin, for example Poly-Vinyl Chloride, acronym PVC, for example acrylonitrile butadiene styrene, acronym ABS, for example polystyrene, acronym PS, or other types of thermoplastics.

[0068] According to one embodiment, in a non-limiting manner, the roofing element is made from a mixture of a plastic material, in particular thermoplastic, with a powder of tire particles, called "micronized rubber powder" in English terms.

[0069] For example, Polyvinyl Chloride is recycled from used joinery.

[0070] The use of recycled materials helps to reduce the environmental impact linked to the manufacture of roofing elements.

[0071] Such a plastic material has both good rigidity provided by the use of the thermoplastic and good flexibility and tolerance to deformation provided by the tire particle powder.

[0072] Such a roofing element is lighter than a natural slate tile, so that it can be fitted onto frames designed to receive shingles covering certain roofs. In addition, it is installed like a natural slate tile, using the same hooks and the same tools.

[0073] Such a roofing element has increased mechanical resistance compared to a natural slate and offers better waterproofing than natural slates.

[0074] According to a second aspect, the invention relates to a method of manufacturing a roofing element as described above in which the roofing element is manufactured by injecting a plastic material into a mold.

[0075] According to another embodiment, the roofing element is manufactured by extruding a smooth plate and applying a surface texturizing roller or by compressing the surface, or stamping to form the plurality of reliefs on at least the outer surface of the roofing element.

[0076] According to another aspect, the invention relates to a roof or roof of a building or construction comprising a plurality of roofing elements as described above. previously, wherein said roofing elements are juxtaposed in a direction perpendicular to the slope of said roof and arranged overlapping in the direction of said slope.

[0077] By “roof” is meant any covering with a slope between 1° and 180°.

[0078] Advantageously, the roof comprises crosspieces or battens secured to stringers or rafters forming the roof frame and in which the roof elements are arranged in a staggered pattern on the crosspieces and each fixed using a hook secured to a crosspiece.

[0079] The fixing hooks comprise, for example, a central part extending on one side by a first curved part for retaining a roofing element and on the other side by a second part fixed to a crosspiece.

[0080] The overlapping area of ​​a roof element is held by the hook of the roof element above which is placed on top.

[0081] The installation of a roofing element is similar to the installation of natural slate on a roof. Such an installation is known and will not be described further.

[0082] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0083] [Fig. 1] schematically represents a plan view of a roof covered with a plurality of roofing elements according to one embodiment of the invention;

[0084] [Fig.2] shows a side view of the roof of [Fig.l];

[0085] [Fig.3] is a longitudinal sectional view along the III-III axis of a roofing element of [Fig.l];

[0086] [Fig.4] is a cross-sectional view along axis IV-IV of a roofing element of [Fig.l];

[0087] [Fig.5] is a top view of a roof element of [Fig.l];

[0088] [Fig.6] represents the definition of the overlapping zones of a roof element; And

[0089] [Fig.7] is a table representing the recovery rate versus the slope of the roof and the geographical area.

[0090] In the remainder of the description, we consider an orthonormal base X, Y, Z, defined with respect to the roof element 10 in which we find:

[0091] - a longitudinal axis X, horizontal and extending from left to right on [Fig.3];

[0092] - a transverse axis Y, horizontal, perpendicular to the longitudinal axis X and extending from front to back on [Fig.3]; and

[0093] - a vertical axis Z, orthogonal to the longitudinal axes X and transverse Y and extending from bottom to top on [Fig.3].

[0094] The expressions "exterior" and "interior" refer to the exterior part in contact with the exterior environment and to the interior part in contact with the structure of the building, in the assembled position of the assembly in Figures 1 and 2.

[0095] The expressions “lower” and “upper” refer to the lower part and the upper part along the longitudinal axis X of the roof element.

[0096] As illustrated, the roof element 10 has a rectangular shape delimited by two large lateral sides 10a, 10b and two small lateral sides 10c, 10d. The longitudinal direction X corresponds to a direction parallel to the large lateral sides 10a, 10b and the transverse direction Y is perpendicular to the longitudinal direction.

[0097] Alternatively, the roof element 10 may have a square shape.

[0098] Generally speaking, the roof element 10 has the shape of a quadrilateral whose four angles are right angles.

[0099] Figures 1 and 2 very schematically represent a partial plan of a roof 1 made using roofing elements 10 according to the invention.

[0100] The roof or roof 1 is here inclined and comprises a plurality of roof elements 10 in the form of rectangular plates juxtaposed in a direction Z perpendicular to the slope of said roof 1 and arranged to overlap in the direction of said slope.

[0101] The roofing elements 10 are placed in a staggered pattern on wooden crosspieces or battens 2 secured to stringers or rafters 3 forming the roof frame (not shown). Alternatively, the roofing elements could be placed on a boarding.

[0102] As seen in Figures 2 and 6, each roof element 10 comprises a first zone Z1 called “covering”, placed on a crosspiece 2, a second zone Z2 called “exposure”, in contact with a roof element superimposed in the direction of the slope, and a third intermediate zone Z3 called “false exposure”. All of the zones Z1, Z2, Z3 delimit the total length L of the roof element 10.

[0103] Each roof element 10 is held in its second zone Z2 of pureau, in particular its lower side 10d, using a fixing hook 4 fixed to the crosspieces 2.

[0104] The fixing hooks 4 comprise a central part 4a extending on one side by a first curved part 4b for retaining a roof element 10 and on the other side by a second part 4c fixed to a crosspiece 2.

[0105] The first covering zone Zl of a roof element is held by the hook of the roof element 10 above which is placed on top.

[0106] The installation of a roofing element 10 is similar to the installation of a slate natural on a roof. Such an installation is known and will not be described further.

[0107] As illustrated in detail in [Fig.5], each of the roof elements 10 is delimited by two longitudinal sides 10a, 10b of large dimension, two transverse sides 10c, 10d of small dimension, smaller than that of the longitudinal sides 10a, 10b. Said sides 10a, 10b, 10c, 10d delimit a closed peripheral contour of said roof element 10.

[0108] Each of the roof elements 10 is further delimited by an exterior face or surface 12, intended to be exposed to the weather and an opposite, interior face or surface 14, advantageously intended to come to bear on the roof frame 1.

[0109] The outer surface 12 extends here along an extension plane XY.

[0110] As illustrated in [Fig.3], the outer face 12 of each roof element 10 comprises a plurality of reliefs 16 extending in a non-ordered manner within the extension plane XY of the outer surface 12.

[0111] The plurality of reliefs 16 characterizes the surface roughness of the outer surface 12 of the roofing element 10.

[0112] The reliefs 16 may form straight and / or curved line profiles and certain reliefs 16 may or may not have the same shape.

[0113] By “unordered” distribution, we mean that these reliefs 16 are distributed on the outer surface 12 in an aperiodic manner.

[0114] The plurality of reliefs 16 comprises grooves or furrows, and projections.

[0115] The reliefs 16 are here not regularly spaced from each other over the entire exterior surface 12 of the roofing element 10.

[0116] The plurality of reliefs 16 extend multidirectionally in the XY plane of the outer surface 12.

[0117] The plurality of reliefs 16 has a variation in thickness Ae around the XY plane of extension of the outer surface 12 of between 0.1 mm and 2 mm, preferably between 0.1 mm and 0.5 mm. The XY plane of extension is here a mean plane.

[0118] In other words, the variation in thickness Ae of the plurality of reliefs 16 corresponds to the maximum distance between the projections and the hollows characterizing the surface roughness of the outer surface 12.

[0119] The multidirectional surface roughness promotes the flow of fluids between two superimposed roof elements.

[0120] Furthermore, such surface roughness formed by the plurality of reliefs 16 distributed over the outer surface 12 of the roofing element 10 prevents fluids from rising towards the upper part of the slate by capillarity and thus into the overlap zone which opens into the framework.

[0121] As illustrated in Figures 3 and 4, the inner face 14 of the roof element 10 is smooth.

[0122] Alternatively, it could also be provided that the inner face 14 of each roof element 10 comprises a plurality of reliefs (not shown) extending in an unordered manner within the plane of extension of the inner surface 14 so as to characterize a multidirectional surface roughness of said inner surface 14.

[0123] The plurality of reliefs of the inner surface 14 has a variation in thickness around the plane of the inner surface 14 of between 0.1 mm and 2 mm, preferably between 0.1 mm and 0.5 mm.

[0124] As illustrated in [Fig.4], the longitudinal sides or edges 10a, 10b of each roof element 10 comprise a thickness reduction or chamfer 12a connecting to the outer surface 12 and defined by a length c and an end thickness b.

[0125] Each of the chamfers 12a is flat and extends obliquely from a longitudinal edge 10a, 10b towards the outer surface 12 of the roofing element 10.

[0126] The length c corresponds to the distance measured between the start of the variation in thickness Ae of the reliefs 16 and a longitudinal edge 10a of the roofing element 10. The distance c is between 1mm and 15mm, preferably between 2mm and 10mm.

[0127] The end thickness b corresponds to the thickness of the longitudinal edge 10a of the roofing element 10. The end thickness b depends on the average thickness E of the roofing element 10 and is between 0.5mm and E-0.5mm, preferably between 1mm and half of the average thickness E.

[0128] As illustrated in [Fig.3], the transverse sides or edges 10c, 10d of each roof element 10 include a thickness reduction or chamfer 12b connecting to the outer surface 12 and defined by the length c and the end thickness b, according to the equations above.

[0129] Each of the chamfers 12b is flat and extends obliquely from a longitudinal edge 10c, 10d towards the outer surface 12 of the roofing element 10.

[0130] In other words, the four sides of the roofing element 10 comprise a reduction in thickness or chamfer 12a, 12b.

[0131] The chamfers 12a, 12b make it possible to avoid the concentration and coalescence of drops on the lower edge 10d of the roofing element and thus to avoid the concentration of dust, as well as the development of plants. Indeed, the flow of fluid is oriented from the upper transverse edge 10d of the roofing element 10 towards the lower transverse edge 10d of said roofing element 10, which makes it possible to avoid the concentration of fluids on the lower transverse edge 10d.

[0132] The roof element 10 is made of non-porous and hydrophobic synthetic material.

[0133] For example, the roofing element 10 is made from a plastic material, in particular thermoplastic.

[0134] Such a plastic material has good rigidity conferred by the use of thermoplastic.

[0135] In a non-limiting manner, a plastic material could be mixed with a powder of tire particles, called “micronized rubber powder” in Anglo-Saxon terms.

[0136] For example, Polyvinyl Chloride is recycled from used joinery.

[0137] Tire particle powder provides good flexibility and tolerance to deformation.

[0138] Such a roofing element 10 is lighter than a natural slate, so that it can be fitted onto frames designed to receive shingles covering certain roofs. In addition, it is installed like a natural slate tile, using the same hooks and the same tools.

[0139] Such a roofing element 10 has increased mechanical resistance compared to a natural slate tile and offers better sealing than natural slate tiles.

[0140] The roof element 10 is manufactured by injecting a plastic material into a mold.

[0141] Alternatively, the roofing element 10 may be manufactured by extruding a smooth plate and applying a surface texturizing roller or by compressing the surface, or stamping to impart the rough surface condition to the outer and / or inner surface of the roofing element 10.

[0142] The method of manufacturing the roofing element 10 is not limited to the methods described.

[0143] Thanks to the roofing element made of non-porous and hydrophobic material, the problem of fluid movement by capillarity known in natural slates and from fiber cement is eliminated.

[0144] In addition, it is thus possible to considerably reduce the overlap rates between roofing elements, which makes it possible to reduce the mass per square meter of the roofing elements on the roof.

[0145] The surface roughness makes it possible to avoid the suction phenomena observed between hydrophobic roof elements having smooth external surfaces, to improve the evacuation of fluids and to avoid the retention of fluids which can promote the concentration of particles, or even the development of vegetation between two superimposed roof elements. Thus, the service life of the roof elements and the waterproofing of the roof are increased.

Claims

Claims

1. Roofing element (10), in particular intended to cover a framework of a construction, comprising an outer surface (12) extending along an extension plane (XY) and an inner support surface (14) opposite the outer surface (12), the roofing element (10) being delimited by two longitudinal sides (10a, 10b) and two transverse sides (10c, 10d), said sides (10a, 10b, 10c, 10d) delimiting a closed peripheral contour of said roofing element, said roofing element (10) is made of non-porous and hydrophobic materials,characterized in that the entire outer surface (12) comprises a plurality of reliefs (16) extending in an unordered and multidirectional manner within the plane (XY) of extension of the outer surface (12) and in that the entire inner surface (14) of the roofing element (10) comprises a plurality of reliefs extending in an unordered manner characterizing a multidirectional surface roughness.,

2. Roofing element (10) according to claim 1, in which the plurality of reliefs (16) has a variation in thickness (Ae) around the plane (XY) of extension of the outer surface (12) of between 0.1mm and 2mm, preferably between 0.1mm and 0.5mm.

3. A roofing element (10) according to any preceding claim, wherein at least the longitudinal sides (10a, 10b) each comprise a chamfer (12a) connecting to the outer surface (12) and defined by a length (c) and an end thickness (b).

4. Roofing element (10) according to claims 2 and 3, wherein the length (c) defining the chamfer (12a) is equal to the distance measured between the start of the variation in thickness (Ae) of the reliefs (16) of the outer surface (12) and a longitudinal side (10a) of the roofing element (10), said distance (c) being between 1mm and 15mm, preferably between 2mm and 10mm and wherein the end thickness (b) is equal to the thickness of the longitudinal side (10a) of the roofing element (10) and depends on the thickness (E) of the roofing element (10).

5. Roofing element (10) according to claim 4, wherein the end thickness (b) is between 0.5mm and the thickness (E) of the covering element minus 0.5mm, preferably between 1mm and half the thickness (E) of the roofing element.

6. Roof element (10) according to any one of claims 3 to 5, wherein the transverse sides (10c, 10d) of the roofing element (10) each comprise a chamfer (12b) connecting to the outer surface (12) and defined by the length (c) and the end thickness (b).

7. A roofing element (10) according to any preceding claim, wherein the roofing element (10) is made from a plastic material.

8. A method of manufacturing a roofing element (10) according to claim 7, wherein the roofing element (10) is manufactured by injecting a plastic material into a mold.

9. A method of manufacturing a roofing element (10) according to claim 7, wherein the roofing element (10) is manufactured by extruding a smooth plate and applying a surface texturizing roller or by compressing the surface, or stamping to form the plurality of reliefs (16) on at least the outer surface of the roofing element (10).

10. A building roof (1) comprising a plurality of roof elements (10) according to any one of claims 1 to 7, wherein said roof elements (10) are juxtaposed in a direction (Z) perpendicular to the slope of said roof (1) and arranged overlapping in the direction of said slope.

11. Roof (1) according to claim 10, comprising crosspieces (2) secured to stringers (3) forming the roof frame and in which the roof elements (10) are arranged in a staggered pattern on the crosspieces (2) and each fixed using a hook (4) secured to a crosspiece (2).