Fastening System for Large-Area Metal Roof Coverings or Wall Claddings

Abstract

The invention relates to a fastening system for large-area roof coverings or wall claddings. The object is to create a fastening system which is structurally simple, consists of few parts, is fast to install and is suitable for high negative wind loads. Fastening is achieved within two upwardly projecting longitudinal ribs 2, which are formed by upwardly projecting sheet metal flanks 11. These sheet metal flanks 11 are bent up and provided with projections 13. According to the invention, T-shaped base bars 3 are disposed and fastened within the upwardly projecting longitudinal ribs 2, either continuously or only in some places. The horizontal wide limb of the T-shaped base bars 3, designated as foot limb 5, can be disposed upwardly or downwardly. The T-shaped base bar 3 has recesses 6 formed left and right in the vertical limb of the T-shaped base bar 3 and reaching into the foot limbs 5. Specially formed projections 13 of the sheet metal flanks 11 of the roof elements, sheet metal plates or sheet metal strips 1 engage in these recesses 6. These preformed projections 13 result in a form-fitting joint in conjunction with press plates 9 that can be disposed at or on the central limb 4. The press plates 9 are appropriately fastened with the base bar head 7 in a form-fitting manner or, for example, with screws. The press plates 9 are formed such that the press plates 9 span over the projections 13 of the sheet metal flanks 11 of the roof elements, sheet metal plates or sheet metal strips 1 positioned side by side. This creates a durable form-fitting joint by means of the T-shaped base bar 3 (or base element), central limb 4 and press plate 9. At the upper ends of the upwardly projecting lateral sheet metal flanks 11, the whole longitudinal rib is closed towards the top with a cover strip 12.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is the U.S. national stage of International Application No. PCT/162019/000411, filed on 2019 May 21. The international application claims the priority of DE 102018112135.0 filed on 2018 May 19; all applications are incorporated by reference herein in their entirety.

BACKGROUND

[0002] The invention relates to a fastening system for large-area metal roof coverings or wall claddings for the fastening of sheet-like roof elements, sheet metal plates or sheet metal strips positionable side by side on roof or wall substructures, wherein the roof elements, sheet metal plates or sheet metal strips may be designed flat, corrugated or profiled.

[0003] With installed sheet metal strips positioned side by side or large-area sheet metal roof plates for roof coverings or wall claddings, on the one hand, fastening means that penetrate the roof covering should be abstained from, but on the other hand, there is a risk of suction effects caused by strong gusts of wind or gales, requiring secure fastening of the roof covering on the underlying load-bearing substructure. However, the individual adjacent roof metal sheets must allow gapless covering of roof or wall areas that may in part be very large, of different inclination and of different curvature. For specific roof shapes, this curvature alone may cause the suction effect to be additionally reinforced in individual areas. The alternation between positive and negative wind loads and temperature fluctuations introduce additional loads. The requirements to the roof fastening are to keep under control the effects of positive wind loads (pressure forces), negative wind loads (pull forces), expansions when heating up and contraction when cooling down (thrust and shear forces) and still to ensure tightness. Therefore, a construction and installation method has gained acceptance, where the individual sheet metal strips or sheet metal plates are held along longitudinal ribs on the roof covering of the roof or wall substructure. Various types of roof fastening are known, where fastenings are used for safety reasons and which penetrate the roof covering at different locations spaced from each other, which will always result in problems of tightness of such roof or wall coverings. This is therefore unsuitable for many roof and wall configurations and requires a high maintenance effort. Therefore, roof and wall coverings are preferred, which dispense with the need of roof penetration. Generally, holders that are arranged inside are therefore used, which are to fasten the roof covering reliably. These are arranged at specific distances between each other, depending on the construction type. Therein, one sheet metal strip overlaps the next one, in order to produce tightness. Such a technical solution is known from EP 0 530 483 A1, where a roof covering is made by means of profiled metal strips laid side by side, wherein on one side an adjacent metal strip overlaps the next metal strip in the same direction along a longitudinal rib shaped to protrude upwards. The metal strips are held on the roof substructure by means of different folding seams which are fastened in a hook shaped holder in a form-fitting manner to ensure sufficient fastening. However, this fastening solution requires sheet metal strips that are preformed differently. The fastening is done by a hook-shaped holder fastened to the load-bearing substructure. As is general practice, it is screw-fastened to the substructure. The hook-shaped holder can be of various shapes. However, this method of fastening only allows a purely form-fitting fastening of the sheet metal strips with the screw-fastened holder located inside. Considering extended periods, the form-fitting joint can bend open due to the various acting forces, and the strength can become so low that the individual sheet metal strips may well be stripped off in gales.

[0004] EP 204 123 B1 describes a modular system for a wall structure, where plate-shaped facade structures can be snapped into a holding element and where flanges are disposed at a specific angle on each plate element at the left and right, the free ends of which flanges are bent over such that this results in projections at the ends to engage with the recesses of a holding element. The holding element is screw-fastened with the substructure. This solution has the disadvantage that this form-fitting joint can withstand high negative wind loads only to a limited extent, and furthermore, this facade structure is not watertight.

[0005] DE 199 41 510 A1 describes another roof covering of sheet metal strips positioned side by side and which, when installed, are joined to each other by longitudinal ribs that form and thereby also sealed. For fastening, so-called holding strips are screw-fastened to the roof substructure. Left and right at the holding strip, upwardly protruding hooks are arranged, whose head parts are bent over to one side in a hook shape. At the left and right, the sheet metal strips have perpendicularly upright longitudinal ribs. One side of the sheet metal strip engages the hook from below while the other side engages the head part and the engaged longitudinal rib also in a hook-like manner, making the form-fitting joint. Here, too, the purely form-fitting joint, which is not permanent in the long term and is also no secure heavy-duty fastening, is also disadvantageous.

[0006] US 2009/0094921 A1 also describes a fastening system of another roof fastening, where the fastening to the roof substructure is achieved by upwardly projecting longitudinal ribs, with the ends of the upwardly projecting protruding sheet metal flanks of adjacent so-called tiles mutually engage and a standing seam is formed. In order to prevent this form-fitting joint from widening up under load, clips are fastened to have a kind of clamping effect. The problem here is that this kind of fastening system does not stabilize the tiles (sheet metal strips) sufficiently and immobilize them because these are only fixed at the upper end of the standing seams and the tiles may therefore be deformed under the forces acting in various ways. Here, the roof covering may be considerably deformed.

SUMMARY

[0007] The invention relates to a fastening system for large-area roof coverings or wall claddings.

[0008] The object is to create a fastening system which is structurally simple, consists of few parts, is fast to install and is suitable for high negative wind loads.

[0009] Fastening is achieved within two upwardly projecting longitudinal ribs 2, which are formed by upwardly projecting sheet metal flanks 11. These sheet metal flanks 11 are bent up and provided with projections 13. According to the invention, T-shaped base bars 3 are disposed and fastened within the upwardly projecting longitudinal ribs 2, either continuously or only in some places. The horizontal wide limb of the T-shaped base bars 3, designated as foot limb 5, can be disposed upwardly or downwardly. The T-shaped base bar 3 has recesses 6 formed left and right in the vertical limb of the T-shaped base bar 3 and reaching into the foot limbs 5. Specially formed projections 13 of the sheet metal flanks 11 of the roof elements, sheet metal plates or sheet metal strips 1 engage in these recesses 6. These preformed projections 13 result in a form-fitting joint in conjunction with press plates 9 that can be disposed at or on the central limb 4. The press plates 9 are appropriately fastened with the base bar head 7 in a form-fitting manner or, for example, with screws. The press plates 9 are formed such that the press plates 9 span over the projections 13 of the sheet metal flanks 11 of the roof elements, sheet metal plates or sheet metal strips 1 positioned side by side. This creates a durable form-fitting joint by means of the T-shaped base bar 3 (or base element), central limb 4 and press plate 9. At the upper ends of the upwardly projecting lateral sheet metal flanks 11, the whole longitudinal rib is closed towards the top with a cover strip 12.

DETAILED DESCRIPTION

[0010] The object of the invention is to create a fastening system for large-area metal roof coverings or wall claddings for the fastening of sheet-like roof elements, sheet metal plates or sheet metal strips positionable side by side on roof or wall substructures, which is structurally simple, consists of only few parts, is fast to install and is suitable for high negative wind loads.

[0011] The object is achieved by the characteristics of the first patent claim, according to the invention. Further purposeful embodiments of the invention are the object of the further dependent claims. The fastening system for large-area metal roof coverings or wall claddings according to the invention is suitable for the fastening of two or any number of sheet-like roof elements, sheet metal plates or sheet metal strips positionable side by side on roof or wall substructures, wherein the roof elements, sheet metal plates or sheet metal strips 1 may be designed differently, such as flat or corrugated or profiled. Fastening is achieved within two upwardly projecting longitudinal ribs 2, which are formed by sheet metal flanks 11 that project upwardly at the sides. These sheet metal flanks 11 are preferably bent up at a right angle, however, other angles (obtuse or acute) are also conceivable. The longitudinal ribs 2 can be parallel or at an angle to each other on the covering and are distributed over the roof covering or wall cladding. According to the invention, the roof or wall substructure has T-shaped base bars 3 disposed and fastened within the upwardly projecting longitudinal ribs 2, either continuously or only in some places (then designated as base elements). The horizontal wide limb of the T-shaped base bars 3 (or base elements), designated as foot limb 5, can be disposed upwardly or downwardly. The T-shaped base bar 3 has recesses 6 formed on the left and right in the vertical limb of the T-shaped base bar 3, designated as central limb 4, and reaching into the foot limbs 5. Specially formed projections 13 of the lateral sheet metal flanks 11 of the roof elements, sheet metal plates or sheet metal strips 1 engage in these recesses 6. This preformed projections 13 result in a form-fitting joint in conjunction with press plates 9 that may be disposed at or on the central limb 4. The press plates 9 are generally disposed in multiple numbers at specific intervals. However, it is also possible that they are formed as continuous bar-like press plates 9. The press plates 9 are fastened with the base bar head 7 in a suitable form-fitting manner or, for example, screw-fastened. A cohesive joint is also possible for specific roof coverings. The press plates 9 are formed such that press plates 9 span over the projections 13 of the sheet metal flanks 11 of the roof elements, sheet metal plates or sheet metal strips 1 positioned side by side. This creates a durable form-fitting joint by means of the T-shaped base bar 3 (or if distributed in pieces, to be designated a base element), central limb 4 and press plate 9. At the upper ends of the upwardly projecting lateral sheet metal flanks 11, the whole longitudinal rib is closed towards the top with a cover strip 12.

[0012] A particularly durable, permanent, form-fitting joint between the roof elements, sheet metal plates or sheet metal strips 1 and the T-shape base bar or the T-shaped base element 3 with its central limb 4 and the foot limbs 5 in the fastening system for large-area metal roof coverings or wall claddings is achieved if the dimensions and shapes of the projections 13 in the sheet metal flanks 11 correspond with the dimensions and shapes of the recesses 6 in the central limb 4 and in the foot limbs 5. The dimensions and shapes of the press plates 9 are preferably also matched with the dimensions and shapes of the projections 13.

[0013] It is of considerable advantage if the two recesses 6 in the central limb 4 and in the foot limbs 5 are symmetrical in the fastening system for large-area metal roof coverings or wall claddings. Then the roof elements, sheet metal plates or sheet metal strips 1 with the preformed projections 13 and sheet metal flanks 11 can be formed identically at the left and right (also symmetrical). This offers considerable savings of time and costs already when manufacturing the preformed roof elements, sheet metal plates or sheet metal strips 1. In addition, the mounting position is then not predefined, resulting in advantages during the roof or wall installation at the site.

[0014] In the fastening system for large-area roof coverings or wall claddings, different shapes of the recesses 6 and corresponding projections 13 can advantageously be used. Thus, the two recesses 6 in the central limb 4 and in the foot limbs 5, including the shape of the press plate 9, may be formed as a dovetail, oval or circular cross-section in the pressure area.

[0015] In a simple manner, the security against negative wind loads can be considerably improved if the fastening system for large-area roof coverings or wall claddings additionally has reinforcement bars 14 disposed in the projections 13 of the sheet metals flanks 11. These reinforcement bars 14 are inserted from the front side into the projections 13 or are pre-inserted. Preferably, the cross-sections of the reinforcement bars 14 are matched with the cross-sections of the projections 13. This prevents the relatively thin-walled sheet metal roof elements, sheet metal plates or sheet metal strips 1 from deforming with time under the acting forces and the form-fitting joint from being lost. It is also conceivable that the cross-sections differ from each other. Thus, triangular or quadrangular cross-sections of the reinforcement bars 14 are conceivable, for example. Using the reinforcement bars results in a force-locking joint that cannot disengage by itself. Furthermore, the reinforcement bars 14 have the effect that the stability of the whole roof between the longitudinal ribs 2 improves considerably. There will hardly be any deformations in the whole roof covering. The roof covering is almost immediately fixed and tensioned mechanically on the roof and wall substructure, retaining its position and shape relative to the roof substructure because the form-fitting joint cannot be bent open.

[0016] In the fastening system for large-area roof coverings or wall claddings according to the invention, the form-fitting joint is most secure and stable if the dimensions and the cross-sectional shape of the reinforcement bars 14 are precisely matched with the dimensions and cross-sectional shape of the projections 13 of the sheet metal flanks 11 and also with the cross-sectional shape of the recesses 6.

[0017] Instead of a form-fitting joint of the press-plates 9 with the base bar head 7 in the fastening system for large-area roof coverings or wall claddings, the press plates 9 fastened to the central limb 4 can also be fastened at suitable intervals to the base bar head 7 in a force-locking manner by headed screws 10, which are inserted at specific intervals depending on the load.

[0018] In the fastening system for large-area roof coverings or wall claddings, the T-shaped base bars 3 or the T-shaped base elements 3 can be fastened to the roof or wall substructure by means of accordingly dimensioned base screws 8, arranged in a staggered or pairwise manner, for reasons of strength.

[0019] In the fastening system for large-area roof coverings or wall claddings, it is of advantage if the T-shaped base bars 3 and/or the press plates 9 are designed as profile rails. The T-shaped base bar 3 or also the press plates 9 may be disposed in sections with spaces between them or, for reasons of strength and stability, also continuously along the whole extension of the roof, i.e. extending without any gap.

[0020] To provide for reliable sealing against weathering effects, specifically against any humidity, the fastening system for large-area roof coverings or wall claddings has continuous cover strips 12 joined to the top of the longitudinal ribs 2 by means of a form-fitting folded seam joint.

[0021] For specific wider designs of the longitudinal ribs, the fastening system for large-are roof coverings or wall claddings may have the T-shaped base bars 3 or T-shaped base elements 3 with the press plates 9 in an inverse position and fastened to the roof or wall substructure by means of central through-going fastening screws 15.

[0022] Depending on the construction and material of the respective roof covering, the reinforcement bars 14 of the fastening system for large-area roof coverings or wall claddings may optionally be made of stainless steel, aluminium or also of various plastic materials, through to rubber materials or fabric composites.

[0023] It may also make sense if the additional reinforcement bars 14 of the fastening system for large-area wall coverings or wall claddings are made of different materials. For example, a plastic sheath can compensate different expansions and frictions between metal reinforcement bars 14 and the metal sheet of the roof covering.

[0024] To prevent the reinforcement bars 14 in this fastening system from slipping out of projections 13, particularly in the case of steep large-area wall coverings or vertical wall claddings, the reinforcement bars 14 may be designed with linear, helical or locally disposed protrusions 17. This causes them to grip into the surface within the projections of the respective roof material.

[0025] In the fastening system for large-area wall coverings or wall claddings, it is also possible to draw in continuous ropes into the projections 13, instead of the inserted reinforcement bars 14. As needed, these continuous ropes can be clamped taut at each end and the whole roof covering can thus be specially tied down and fixed to the roof or wall structure. Furthermore, the ropes can be drawn in under tension (stretched), with the cross-section of such ropes expanding again after relaxation and filling the space of recess 6 completely. Both steel and other permanent weatherproof rope types are suitable. Thus, for example, the ropes may be made of plastic materials or carbon fibres, wherein these may additionally be impregnated with curable synthetics resins.

[0026] The fastening system for large-area metal roof coverings or wall claddings using upwardly projecting longitudinal ribs 2 ensures safe, stable, storm-proof fastening of sheet-like roof elements, sheet metal plates or sheet metal strips 1 positionable side by side, both on roofs of various inclinations and curvatures and on inclined, vertical or overhanging wall structures, and it is also tight against any climatic influences. It consists of few structurally different individual elements, is cost-saving, fast to install and can be designed for very high negative wind loads. In addition, the non-negligible pull and shear forces acting on large coverings, caused for example by thermal expansions are reliably compensated without damage.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The invention shall be explained in detail in one exemplary embodiment by reference to FIGS. 1 to 4.

[0028] FIG. 1 shows the cross-section through a fastening system according to the invention within a longitudinal rib 2 with pairwise screw fastening of the T-shaped base bar 3 to a roof or wall substructure (not drawn).

[0029] FIG. 2 shows a fastening system with inserted reinforcement bars 14.

[0030] FIG. 3 shows a fastening system with a screw-fastened press plate 9 having a specially designed base element head 7.

[0031] FIG. 4 shows a wide design with a T-shaped base bar 3 arranged in top position and screw-fastened in a through hole and secured by means of a pair of inserted reinforcement bars 14 having protrusions 17 on them.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] FIG. 1 shows the cross-section through a preferred embodiment of a fastening system according to the invention within a longitudinal rib 2 with symmetric pairwise screw-fastening by two base screws 8 of the T-shaped base bar 3 on a roof or wall substructure not depicted in the drawing. The base bar head 7 as the end of the central limb 4 of the T-shaped base bar 3 is complementary to a connection recess with a T-shaped undercut in the press plate 9, also designed in a T-shape. The T-shaped base bar 3 is screw-fastened to the roof or wall substructure with its wide upper bar down. The large upper bar then forms the left and right foot limbs 5 which are recessed in an almost semi-circular shape. The central limb 4 is straight and the base bar head 7 is T-shaped. Instead of the T-shaped joining solution between the base bar head 7 and the press plate 9, a dovetail joint may be designed. This has advantages during installation because the press plate 9 is pushed over the base bar head 7 from the front side. The press plate 9 also has almost semi-circular recesses formed left and right and open towards the bottom. In this way, an almost oval recess 6 is produced. After the T-shaped base bars 3 have been fastened to the roof or wall substructure using the base screws 8, the two preformed roof elements, sheet metal plates or sheet metal strips 1 are inserted left and right into the T-shaped base bars 3. The roof elements, sheet metal plates or sheet metal strips 1 are provided with almost oval projections 13 designed in continuation to a double bend. This is of advantage, ensuring that the two flat portions of the left and right roof elements, sheet metal plates or sheet metal strips 1 can rest on the roof or wall substructure over the full flat area to the greatest possible extent.

[0033] As a rule, this is a beam, joist or girder construction because such roof coverings are not installed on planar substructures. The shapes and positions of the projections 13 correspond in their dimensions and cross-sections with the dimensions and cross-sections of the recesses 6. The roof elements, sheet metal plates or sheet metal strips 1 continue upwards as sheet metal flanks 11 that project upwardly at a right angle. When the roof elements, sheet metal plates or sheet metal strips 1 have been inserted into the T-shaped base bars 3 or base elements, the press plates 9 are slid onto them in a suitable manner from the front side. When the roof elements, sheet metal plates or sheet metal strips 1 are now fixed within the longitudinal ribs 2, a continuous cover strip 12 is installed at the upper end of the sheet metal flanks 11 by making a folding seam. This is done automatically by means of a suitable folding machine. The longitudinal rib 2 is thereby closed in a climate-proof manner and a permanent, mechanically secure fastening to the roof or wall substructure is produced.

[0034] FIG. 2 shows an equivalent embodiment of a fastening system for large-area metal roof coverings or wall claddings, as already described above in FIG. 1. However, reinforcement bars 14 are additionally inserted or slid into the recesses 6 left and right. For particular designs of the roof coverings, it may be sufficient that a reinforcement bar 14 is inserted or slid in only on one side. Here, these reinforcement bars 14 are almost of an oval design and their dimensions and cross-sections correspond with the projections 13 of the roof elements, sheet metal plates or sheet metal strips 1. This improves the strength of the construction considerably. Depending on the dimensioning of the reinforcement bars 14, the mechanical stability at the bottom in the area of the stable roof or wall substructure can be freely adjusted by appropriately larger or smaller cross-sections being pre-inserted or slid in posteriorly. Thus, the security against negative wind loads is considerably improved. Preferably the cross-sections of the reinforcement bars are matched with the cross-sections of the projections 13. This prevents the relatively thin-walled sheet metal roof elements, sheet metal plates or sheet metal strips from deforming with time under the acting forces and the form-fitting joint from being lost. The replacement bars 14 produce a force-locking, permanent joint immediately in the area of the planar roof covering (roof tile).

[0035] FIG. 3 shows a fastening system for large-area metal roof coverings or wall claddings for fastening sheet-like roof elements, sheet metal plates or sheet metal strips 1 positionable side by side in an embodiment with screw-fastening of the press-plate 9 with a base element head 7 specially shaped for screw-fastening. All other design details are equivalent to the technical embodiment as described under FIG. 1. Here, the base bar head 7 is specially reinforced and enlarged and inside a cavity is disposed such that, here for example, the press plates 9 are simply joined with the T-shaped base bar 3 via the central limb 4 using a self-tapping headed screw 10. This base bar is in turn fastened to the roof or wall substructure not shown by means of two self-tapping base screws 8 used in pair. This advantageous embodiment can be installed faster on the site because the press plates 9 need not be slid in from the front side but can be fitted and screw-fastened from the top.

[0036] FIG. 4 shows a wider embodiment of a fastening system for large-area roof coverings or wall claddings. In this case, the T-shaped base bar 3 and the press plate 9 are in an inverse arrangement as compared with the previous arrangements, i.e. the press plate 9 is disposed at the bottom directly on the roof or wall substructure. Then the preformed roof elements, sheet metal plates or sheet metal strips 1 are placed together with pre-inserted reinforcement bars 14, then the T-shaped base bar 3 is inserted from the top and screw-fastened to the roof or wall substructure together with press plate 9 underneath by means of a through-going fastening screw 15. To improve the stability of this wide roof covering embodiment, two reinforcement bars 14 are inserted here again on the left and right. These may be slid in posteriorly, but are generally already inserted before the T-shaped base bars 3 are inserted in and fastened to the projections 6 of the roof elements, sheet metal plates or sheet metal strips 1. Thus, the negative wind loads or other acting forces cannot lead to any deformations of the roof covering and roof tiles. The reinforcement bars 14, which are made of two materials here, have special protrusions 17 gripping into the material of the roof elements, sheet metal plates or sheet metal strips 1 and permanently preventing slippage of the reinforcement bars 14. The technical solution described above is primarily usable as a fastening system for large-area metal roof coverings or wall claddings for the fastening of sheet-like roof elements, sheet metal plates or sheet metal strips positionable side by side on roof or wall substructures.

LIST OF REFERENCE NUMERALS

[0037] 1 Roof elements, sheet metal plates or sheet metal strips

[0038] 2 Longitudinal ribs

[0039] 3 T-shaped base bars, base elements

[0040] 4 Central limb

[0041] 5 Foot limb

[0042] 6 Recesses

[0043] 7 Base bar head

[0044] 8 Base screws

[0045] 9 Press plates

[0046] 10 Headed screw

[0047] 11 Sheet metal flank

[0048] 12 Cover strip

[0049] 13 Projections

[0050] 14 Reinforcement bars

[0051] 15 Through-going fastening screw

[0052] 16 Folded seam joint

[0053] 17 Protrusions

Claims

1. A fastening system for large-area metal roof coverings or wall claddings for the fastening of sheet-like roof elements, sheet metal plates or sheet metal strips positionable side by side on roof or wall substructures, wherein the roof elements, sheet metal plates or sheet metal strips are designed flat or corrugated or profiled, fastened by means of upwardly projecting longitudinal ribs formed by upright sheet metal flanks and the longitudinal ribs are distributed across the roof covering or wall cladding in parallel or at an angle relative to each other, characterized in that T-shaped base bars (3) are disposed and fastened in a longitudinal direction within the upwardly projecting longitudinal ribs (2) on the roof or wall substructure, recesses (6) are formed in the T-shaped base bars (3) left and right on the central limbs (4) and reach down to the foot limbs (5), projections (13) of the sheet metal flanks (11) of the roof elements, sheet metal plates or sheet metal strips (1) engage in these recesses (6), press plates (9) are fastened to the central limb (4), with the press plates (9) spanning over the projections (13) of the sheet metal flanks (11) of the roof elements, sheet metal plates or sheet metal strips (1) positioned side by side and the sheet metal flanks (11) along the longitudinal ribs (2) being closed towards the top using a cover strip (12).

2. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that the dimensions and shape of the projections (13) in the sheet metal flanks (11) correspond with the dimensions and shapes of the recesses (6) in the central limb (4) and in the foot limbs (5) of the T-shaped base bars (3).

3. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that the two recesses (6) in the central limb (4) and in the foot limbs (5) are formed symmetrically.

4. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that the two recesses (6) in the central limb (4) and in the foot limbs (5) are formed as a dovetail, oval or circular cross-section.

5. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that reinforcement bars (14) are additionally disposed in the projections (13) of the sheet metal flanks (11).

6. The fastening system for large-area roof coverings or wall claddings according to claim 5, characterized in that the dimensions and the cross-sectional shape of the reinforcement bars (14) are matched with the dimensions and cross-sectional shape of the recesses (13) of the sheet metal flanks (11) and of the press plates (9).

7. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that press plates (9) fastened to the central limb (4) are screw-fastened to the base bar head (7) at appropriate intervals by means of headed screws (10).

8. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that the T-shaped base bars (3) are fastened with the roof or wall substructure by means of base screws (8) arranged in a staggered or pairwise manner.

9. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that the T-shaped base bars (3) and/or the press plate (9) are formed as profile rails.

10. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that the cover strip (12) is joined to the sheet metal flanks (11) by means of a form-fitting folded seam oint.

11. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that the T-shaped base bars (3) and the press plates (9) are disposed inversely and both are fastened to the roof or wall substructure by means of a central through-going fastening screw (15).

12. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that the reinforcement bars (14) consist of stainless steel, aluminium, plastic materials or rubber materials.

13. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that the reinforcement bars (14) are formed of different materials.

14. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that the reinforcement bars (14) are formed with linear, helical or locally disposed protrusions (17).

15. The fastening system for large-area roof coverings or wall claddings according to claim 1, characterized in that instead of the inserted reinforcement rods (14), continuous ropes or ropes drawn in under tension and relaxing into place are disposed.