AU760899B2 - Roof cladding - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT 000 *0 0 0S Of 0* 0 Applicant(s) BHP STEEL (JLA) PTY LTD A.C.N. 000 011 058 Invention Title: ROOF CLADDING The following statement is a full description of this invention, including the best method of performing it known to me/us: ROOF CLADDING The present invention relates generally to a roof cladding panel and a method of roof cladding involving a plurality of the roof cladding panels.

Traditional roof cladding involves fixing a series of corrugated sheets to battens which are nailed to and extend transversely across roof rafters. The sheets are screwed to the roof battens with the sheet corrugations being oriented parallel to the rafters thereby allowing rainwater to drain across the corrugated sheet. The battens serve to support the corrugated sheet between adjacent rafters.

According to one aspect of the present invention there is provided a roof cladding panel adapted to be fixed to adjacent roof rafters, the cladding panel comprising a series of corrugations being disposed parallel to each other, said corrugations alone being configured to provide the required inherent stiffness for an unsupported span of the panel between the adjacent roof rafters and to allow drainage of rainwater across the panel, when it is fixed to the roof rafters, without the corrugations retaining rainwater, the corrugations being shaped in cross-section as a sequence of repeating and substantially identical waveforms including a stiffening rib formed continuous with an adjacent web, and wherein one or more of the webs include a stiffening recess being located adjacent and disposed parallel to a respective one According to another aspect of the present invention there is provided a method of roof cladding involving the steps "of S. providing a plurality of roof cladding panels each S 35 comprising a series of parallel corrugations which alone are configured to provide the required inherent stiffness for an unsupported span of the panel between adjacent roof rafters; and fixing each of the panels to the roof rafters wherein water can drain across the panel without the corrugations retaining rainwater.

Advantageously the corrugations of each of the roof cladding panels provides the required inherent stiffness to each of the panels without relying on interlocking of adjacent panels or roof battens or purlins for the required stiffness.

Preferably the stiffening rib in cross-section is convex and generally C-shaped, and the web substantially planar or slightly concave. Thus the series of corrugations in cross-section resemble an undulating waveform with the web and stiffening rib corresponding to the trough and peak, respectively.

Preferably the roof cladding panel is one of a plurality of said panels being configured to adjoin so as to provide roof cladding. More preferably adjacent edge portions of adjacent panels of the plurality of panels are configured 25 to mutually lap. In one embodiment the adjacent edge portions are compliant to each other and thus mutually lap so as to adjoin each other.

In one embodiment one of the adjoining edge portions of one of the panels includes a hook-shaped section with a lip designed to engage a lower face of an adjacent panel.

.3 4 Generally the hook-shaped section is formed in one of the stiffening ribs which laps or nests underneath an adjacent stiffening rib of an adjacent panel.

Preferably the roof cladding panel is cold roll formed from sheet steel. More preferably the sheet steel is of a thickness of less than about 1.00 mm, Generally the roof cladding panel is fixed to the adjacent roof rafters wherein the parallel corrugations extend transverse to the rafters.

In order to facilitate a better understanding of the nature of the present invention several embodiments of a roof cladding panel and method of roof cladding will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side elevational view of a roof cladding panel; 20 Figure 2 are enlarged detail views in side elevation of various features of the panel of Figure 1; Figure 3 is an enlarged detail view in side elevation of adjoining adjacent panels; Figure 4 are enlarged detail views in side elevation 25 of an edge portion of another roof cladding panel and lapping roof cladding panels; Figure 5 is an enlarged detail view in side elevation of further roof cladding panels lapping each other; and Figure 6 is an enlarged detail view in side elevation of other lapping roof cladding panels.

As shown in Figure 1 there is a roof cladding panel designed to be fixed to adjacent roof rafters (not shown) The roof cladding panel 10 includes a series of corrugations disposed parallel to each other and alone 5 being configured to provide the required inherent stiffness for an unsupported span of the panel 10. The corrugations are also configured so that when the panel 10 is fixed to roof purlins or rafters of a roof structure, rainwater can drain across the panel 10 without the corrugations retaining rainwater.

In this embodiment the corrugations are shaped in crosssection as a repeating and substantially identical waveform including a stiffening rib such as 12 formed continuous with an adjacent web such as 14. An upper surface of the stiffening rib 12 is convex and the rib 12 is generally Cshaped in cross-section. The web 14 is in cross-section very slightly concave. The corrugations thus resemble an undulating waveform with the rib 12 and web 14 corresponding to a peak and trough, respectively.

oo o As best shown in Figure 2 the webs 14 each include a stiffening recess such as 16. The stiffening recess 16 is 20 located adjacent and disposed parallel to one of the stiffening ribs 12. The stiffening recess 16 of this embodiment is in cross-section U-shaped. The roof cladding panel 10 of this embodiment is generally elongate with the stiffening ribs 12 extending longitudinal along the panel As illustrated in Figures 2 and 3 one of the opposing edge portions 18 or 20 of the panel 10 is configured to adjoin an adjacent edge portion such as 20A of another panel The edge portion 18 includes a hook-shaped se.ion 26 with a lip designed to contact a lower face of the other panel ,In this embodiment the hook-shaped section 26 is formed in a portion of one of the stiffening ribs 12 which laps or nests underneath an adjacent stiffening rib 12A of the other panel 10A. This effects adjoining of the adjacent roof cladding panels 10 and 6 Although adjoining the adjacent panels 10 and 10A assists in providing additional stiffness to the panels 10 and the required inherent stiffness is provided by the corrugations alone of each of the panels 10 or 10A. That is, each of the panels 10 or 10A alone is inherently stiff without the need for additional stiffness as provided by adjoining of adjacent panels such as 10 or As depicted in Figure 2 the webs 14 of the roof cladding panel 10 each include a cranked portion 30 which further improves the inherent stiffness of the panel 10. The enhanced flexural stiffness of the panel 10 allows the panel 10 to be fixed to adjacent roof purlins or rafters over an increased unsupported span. Furthermore, it is not necessary to provide additional adjoining panels for the primary purpose of stiffening the individual panels.

Rather, a single panel may extend the full length of the rafter with sufficient stiffness for an unsupported span 20 between adjacent rafters.

Figures 4 to 6 illustrate alternative embodiments of the 0. invention and in particular opposing edge portions of adjacent roof cladding panels which permit adjoining of the 25 panels. In these examples, adjacent edge portions of the panels 10 and 10A are generally compliant to each other and thus mutually lap so as to adjoin each other. As shown in Figure 6, a fastener such as a screw 32 is designed to penetrate both of the panels 10 and 10A and engage a roof rafter. For ease of reference like numerals are used to designate similar features/components of these alternative embodiments to those of the previous embodiment as described with reference to Figures 1 to 3.

It is preferable that the roof cladding panels such as are cold roll formed from sheet steel. In the embodiment 7 described in the preceding paragraphs the sheet steel is of a thickness of 0.42mm and is formed of steel strip having a corrosion resistant coating, the steel strip being of the kind commercially available in Australia under the trade mark ZINCALUME or COLORBOND.

The roof cladding panels of the various examples of the invention are preferably adapted to be fixed to a pitched roof structure including adjacent roof rafters. The roof cladding panels are screwed to the adjacent roof rafters with the roof panel corrugations extending transverse to the rafters. The roof panel such as 10 with its integral stiffening features extends unsupported between adjacent roof rafters without the need for roof battens and/or the adjoining of panels to provide each of the panels with the required stiffness. The relatively light gauge material from which the roof panel is cold roll formed provides a lightweight panel which together with its integral stiffening features is relatively stiff across an 9 *20 unsupported span.

Although the cladding panels described are designed so that the corrugations extend transverse to the roof rafters it is possible that a roof cladding panel of another configuration may be fixed with the corrugations extending parallel to the roof rafters. The corrugations of the panel are configured to provide inherent transverse rigidity without requiring additional support between adjacent roof purlins or rafters such as that conventionally provided by battens or purlins.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. For example, the specific form of the roof cladding panel corrugations may vary provided the panel has the required 8 inherent stiffness to be located unsupported between adjacent roof rafters, and the panel when installed does not retain rain water.

All such variations and modifications are to be considered within the ambit of the present invention the nature of which is to be determined from the foregoing description.

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Claims (11)

1. A roof cladding panel adapted to be fixed to adjacent roof rafters, the cladding panel comprising a series of corrugations being disposed parallel to each other, said corrugations alone being configured to provide the required inherent stiffness for an unsupported span of the panel between the adjacent roof rafters and to allow drainage of rainwater across the panel, when it is fixed to the roof rafters, without the corrugations retaining rainwater, the corrugations being shaped in cross-section as a sequence of repeating and substantially identical waveforms including a stiffening rib formed continuous with an adjacent web, and wherein one or more of the webs include a stiffening recess being located adjacent and disposed parallel to a respective one.

2. A roof cladding panel as defined in claim 1 wherein the stiffening rib in cross-section is convex and generally C-shaped, and the web substantially planar or slightly concave. ,oooo A roof cladding panel according to either claim 1 or 2 wherein each of the stiffening ribs has opposing walls 25 which merge to form a crest of that rib, wherein adjacent stiffening ribs are interconnected by said webs, wherein one wall of a said stiffening rib is formed continuous with a first end of a first adjacent web, whereas the other wall is mutually inclined to a second and of a second adjacent 30 web so that a juncture is formed between said other wall and the second adjacent web. A roof cladding panel according to claim 3, wherein S- the stiffening recess is located in the second end of a 35 said web adjacent to juncture. A roof cladding panel as defined in claim 4 wherein the stiffening recess in cross-section is U-shaped.

6. A roof cladding panel as defined in any one of the preceding claims wherein the roof cladding panel is one of a plurality of said panels being configured to adjoin so as to provide roof cladding.

7. A roof cladding panel as defined in claim 6 wherein adjacent edge portions of adjacent panels of the plurality of panels are configured to mutually lap.

8. A roof cladding panel as defined in claim 7 wherein the adjacent edge portions are compliant to each other and thus mutually lap so as to adjoin each other.

9. A roof cladding panel as defined in claim 8 wherein one of the adjoining edge portions of one of the panels includes a hook-shaped section with a lip designed to engage a lower face of an adjacent panel.

10. A roof cladding panel as defined in claim 9 wherein *the hook-shaped section is formed in one of the stiffening 25 ribs which laps or nests underneath an adjacent stiffening rib of an adjacent panel.

11. A roof cladding panel as defined in any one of the preceding claims wherein the roof cladding panel is cold 30 roll formed from sheet steel.

12. A roof cladding panel as defined in any one of the .preceding claims said panel being adapted to fix to the adjacent roof rafters wherein the parallel corrugations 35 extend transverse to the rafters. 11

13. A method of roof cladding involving the steps of: providing a plurality of roof cladding panels according to any preceding claim, each comprising a series of parallel corrugations which alone are configured to provide the required inherent stiffness for an unsupported span of the panel between adjacent roof rafters; and fixing each of the panels to the roof rafters wherein water can drain across the panel without the corrugations retaining rainwater.

14. A roof cladding panel substantially as herein described with reference to the accompanying drawings. A method of roof cladding substantially as herein described. Dated this 25 th day of February 2003 BHP STEEL LIMITED By Its Patent Attorneys: ooooe GRIFFITH HACK oO** Fellows Institute of Patent S 25 Attorneys of Australia 0@ *o oo**