AU781872B2 - A ceiling structure - Google Patents

Description

Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

(ORIGINAL)

IP Australia Documents receiveo on:

O

3 0 APR 2001 Batch No: Name of Applicant: Actual Inventor(s): Address for Service: Invention Title: Boral Australian Gypsum Limited Mr Andrew Close DAVIES COLLISON CAVE, Patent Attorneys, 1 Little Collins Street, Melbourne, Victoria 3000.

"A Ceiling Structure" Details of Associated Provisional Application No: PQ7449/00 11 May, 2000 The following statement is a full description of this invention, including the best method of performing it known to me/us: P OPER'J"SPECIFICATIONSIA CEILMG STRUCTURE dom.3004 01 -2- A CEILING STRUCTURE The present invention relates to a ceiling structure and is particularly concerned with a ceiling structure including a ceiling lining board.

It is conventional for ceiling lining material to be directly supported from floor/ceiling joists above or to be suspended from above by means of hangers. In the latter arrangement, the ceiling lining material may be secured to furring channels which are suspended by hangers from the ceiling joists or, for example, from a concrete roof/floor slab. These furring channels tend to deflect under the load of ceiling lining material and it is important therefore that, for a given surface area of ceiling lining material, the length and number (and spacing) of channels is carefully selected. Deflection may be controlled by the number and location of points at which the furring channels are suspended from above, for instance by hangers. If any or all of these influences are inadequate to prevent 15 deflection, the channel sections may, at best, sag resulting in unsightly bulging of the ceiling lining material or, at worst, fail resulting in collapse of the ceiling structure. It would therefore be desirable to provide a ceiling structure in which the channel sections used to support the ceiling lining material have enhanced structural rigidity.

Accordingly the present invention provides a ceiling structure comprising an elongate support member and sheet-like rigid ceiling lining material supported by the elongate support member, wherein the elongate support member has a channel section at least partly defined by two webs each having an elongate distal edge with said two distal edges being spaced apart and a respective distal flange extending along each of said distal edges, and wherein said lining material abuts and is fixedly secured to both of the distal flanges of the elongate support member to define a box section with the elongate support member.

By the present invention, both distal flanges of the elongate support member are secured to the ceiling lining material, thereby closing the channel section of the support member to form a box section which greatly increases the strength of the support member. The P.'OPERk SPECIFICATIONSA CEILING STRUCTURE do.30.04 01 -3enhanced structural rigidity of the support member as a consequence of formation of the box section may also provide advantages in terms of sound-proofing.

In the conventional arrangements described, structure-borne sound from above is too readily communicated through the ceiling joists and/or hangers to the ceiling immediately below. Even though sound insulating hangers and materials are available to alleviate this problem, there is a continuing need to reduce the amount of acoustic bridging between adjacent floor and ceiling structures. When using suspended furring channels, the problem may not be addressed simply by reducing the number of hangers used to support each channel and thus the number of conduits through which sound can be transmitted. As has been explained, if there is inadequate support for the furring channels from above, the ceiling lining will sag due to deflection of the channels under load, or the ceiling structure will fail.

15 One consequence of employing the box section described is that, for a given expanse of ceiling lining material, the extent to which the channel sections are supported from above may be reduced when compared with conventional ceiling support systems which do not have the same structural rigidity. Thus, where hangers are used to support the channel sections, the number of hangers required to avoid deflection may be reduced. In turn, this reduces acoustic bridging between adjacent floor and ceiling structures.

oo In one embodiment of the invention it may be acceptable to support the elongate support member only at its ends, for instance by fixing to respective walls. The present invention may thus readily enable large expanses of ceiling lining material to be supported without the need for the elongate support member to be suspended from above intermediate its ends to avoid sagging. This also has clear advantages in terms of reducing acoustic bridging.

For very large expanses of ceiling lining material, the elongate support member may additionally be suspended from above by means of one or more hangers, preferably one or PAOPER'JcSPECIFICATIONSA CEILING STRUCTURE doc)04 01 -4more acoustically insulated hangers, but the number of these may be reduced by virtue of the rigidity of the box-section, thereby reducing acoustic bridging from above.

Also, with larger expanses an array of more than one elongate support member may be required, each elongate support member having a channel section at least partly defined by two webs each having an elongate distal edge with said two distal edges being spaced apart and a respective distal flange extending along each of said distal edges, wherein the lining material abuts and is fixedly secured to both of the distal flanges of all of the elongate support members to define a box-section with each elongate support member. The use of an array of elongate support members may reduce or obviate the need to suspend any support member from above for a given expanse of ceiling lining material. It is of course i possible to use an array of elongate support members in which any number of members is •suspended from above.

Because of the rigidity of the box-section, no noggings are required between the elongate support members, or between an end elongate support member and an adjacent wall structure. This may help to reduce the depth of a floor/ceiling assembly comprising a ceiling structure according to the invention and an array of joists above the ceiling structure. Thus, if the or each elongate support member extends parallel to the joists, it may be disposed partly between adjacent joists and not necessarily wholly beneath the joists. Any blocking between the joists may be shaped or sized to accommodate the S elongate support member(s) without contact.

The or each elongate support member may be supported or fixed to the respective wall in any of a number of ways. For instance, each end may extend into the respective wall and be supported thereby or supported by a bracket carried by the wall. The opposed ends of the or each elongate support member may be supported differently.

The ceiling lining material preferably comprises one or more lining boards, for example of plasterboard or of timber. Two or more boards will abut each other edge to edge. The ceiling lining material may be secured to the distal flanges of the or each elongate support P.'OPERU.k-SPECIFICATIONS A CEILING STRUCTURE d 3O 04 01 member by any one or more of, for example, bonding agent, clips and fasteners so that the ceiling lining material is directly secured to the flanges. Preferably, threaded fasteners are used. This would be the case where the ceiling structure is fire-rated. In certain situations, for instance where the ceiling structure is non-fire-rated, bonded and threaded fasteners may be employed.

The ceiling lining material may comprise more than one layer of lining board, in which case at least some of the layers may be bonded to each other. However, at least a second layer of lining board may be secured directly to the each elongate support member by means of fasteners. Preferably the join(s) between adjacent lining boards in one layer are not aligned with the join(s) between adjacent lining boards in an adjacent layer.

°Advantageously, insulating material may be provided on the ceiling lining material. The insulating material, which may provide thermal insulation and/or sound insulation, may S* 15 take any appropriate form, including batts, particles, fibres and mats.

The channel section of the or each elongate support member may take any suitable form.

For example, the channel section may be essentially V-shaped. Preferably, however, the channel section includes a base between the webs, in which case the webs may diverge from each other, generally in a V-section, or may extend substantially parallel to each other, generally in a U-section. Preferably, the distal flange associated with each web S projects outwardly away from the other web. A typical channel section which may be used in the present invention is known as a top hat section formed from mild steel, usually galvanised or otherwise coated. Many other appropriate channel sections are known and available from a variety of suppliers, including Stramit and BHP Building Products.

Typically, the elongate support member(s) may be of relatively light gauge if formed from steel or other metal and the channel section may have relatively small depth. However, if the properties of the support member are not sufficient to provide the desired strength or stiffness, this can be alleviated by providing essentially the same profiles in greater gauge and/or depth. Alternatively, two Z-profile elongate members may be secured together to P.'OPER1JcSPECIFICATIONSA CEILING STRUCTIJRE do.30 04 01 -6define the required channel section. Z-sections are currently used for purlins and girts, and extend up to greater gauges and depths than the existing roof and ceiling battens. A Zsection has a central web with spaced opposite flanges along opposed edges of the web, each flange usually being stiffened by a distal lip. Existing Z-sections, for example Zed sections supplied by BHP Building Products, are available with the opposed flanges having different widths to facilitate nesting of two or more of the sections. As proposed, the nested flanges form the base of the channel section and the respective webs of the Zsections form the spaced webs of the channel section extending from the base. The nested flanges may be secured together by any of welding, bonding, bolting, rivetting and, for example, threaded fasteners. Preferably, threaded fasteners are used.

i For a given expanse of ceiling lining material the number of elongate channel members S"used and whether any, or all, of these are suspended from above will depend on a variety of factors. These include the dimensions and configuration of the support member, the 15 material from which the support member is formed, the rigidity and load of (each piece of) the ceiling lining material, the number and spacing of points at which the support members are fixed to the ceiling lining material and the degree of acoustic bridging which is acceptable. By way of illustration, a Stramit 96mm high 1.0mm base metal thickness (BMT) tophat section at 600mm centres may be used to span 3.9m with a single layer of Boral Firestop plasterboard fixed thereto by screw fasteners attached to the flanges of the section. Similarly, a BHP 120mm Topspan 0.9mm BMT section at 600mm centres may be used to span 4.46m with two layers of Boral Firestop plasterboard fixed thereto by screw fasteners. In both of these illustrations, the channel sections may be supported by angles fixed at respective walls, or suspended at each end from above by hangers.

An embodiment of a ceiling structure in accordance with the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a vertical part-sectional view through the joists of a floor/ceiling assembly in accordance with the present invention and Figure 2 is a vertical part-sectional view normal to the view of Figure 1.

P AOPERUc"F3S"9I.O Isp&docwdW7M -7- Referring to Figures 1 and 2, a floor/ceiling assembly 1 including a ceiling structure 2 in accordance with the present invention is shown. The ceiling structure 2 is provided below a floor structure 3 and comprises an array of elongate support members 4 (of which three are shown in Figure 1 and only one in Figure The support members 4 are spanned by a sheet of ceiling lining material 5 which would typically be plasterboard. The figures illustrate a typical arrangement in which two sheets 5a, 5b are bonded to each other.

In the embodiment shown, each support member 4 has a generally U-shaped channel section 6 defined by a base 7 and two spaced webs 8 extending from the base 7, each web 8 having a distal flange 9 extending therealong. The ceiling lining material 5 abuts all of the flanges in the array and is fixedly secured to the flanges by connecting means 11, such as screw threaded fasteners. The latter attach one layer of ceiling lining material 5b to the flanges 9 from below. In this configuration the other layer of lining material 5a is bonded to the layer Sb.

o SThe ceiling sheet 5, webs 8 and base 7 define a box section which is commonly referred to as a top hat configuration. The box section provides sufficient structural rigidity and stability so that the elongated support members 4 may be supported only at respective walls 15 (one of which is depicted in Figure 2) without sagging of ceiling lining material over the distance spanned. Insulating material, shown schematically at 10, may be provided on the ceiling sheet 5 and between the elongated support members 4.

o The support members 4 may be attached to respective walls 15 by use of a support bracket 16, which is generally L-shaped. At the site of attachment the lining material 5 is adapted to receive a portion of the bracket, for instance the lining material 5 may be provided with a groove or notch.

The floor structure 3 includes a floor sheet 12 provided on floor joists 13. For convenience only two such joists are shown in Figure 2. The floor joists 13 support the floor sheet 12.

The floor structure 3 also includes blockings 14 to provide additional rigidity to the floor joists 13. The blockings 14 are usually provided between and perpendicular to the floor P. OPERIJ,,SPECIFICATIONSA CEILING STRUCTURE d-r.3O 04;01 -8joists 13. In the illustrated embodiment the support members 4 are provided in parallel fashion relative to the floor joists 13. In the situation where blockings 14 are not present it can be envisaged how the support members 4 may be disposed in the voids between floor joists 13. This arrangement allows the depth of the floor and ceiling structures 3, 2 to be reduced without compromising the beneficial sound insulating properties of the floor/ceiling assembly.

Those skilled in the art will appreciate that the invention described herein is susceptible to variation and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications which fall within its spirit and scope.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will 15 be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

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Claims (13)

1. A ceiling structure comprising an elongate support member and sheet-like rigid ceiling lining material supported by the elongate support member, wherein the elongate support member has a channel section at least partly defined by two webs each having an elongate distal edge with said two distal edges being spaced apart and a respective distal flange extending along each of said distal edges, and wherein said lining material abuts and is fixedly secured to both of the distal flanges of the elongate support member to define a box section with the elongate support member.

S2. A ceiling structure according to claim 1 wherein the elongate support member is supported only at its ends by fixing to walls.

3. A ceiling structure according to claim 2, wherein the elongate support member is additionally suspended from above by means of one or more hangers. ooooi

4. A ceiling structure according to claim 3, wherein the one or more hangers are acoustically insulated hangers.

A ceiling structure according to any one of the preceding claims comprising an array of more than one elongate support member.

6. A ceiling structure according to any one of the preceding claims, wherein the ceiling lining material comprises one or more lining boards.

7. A ceiling structure according to any one of the preceding claims, wherein the ceiling lining material is secured to the distal flanges of the or each elongate support member by threaded fasteners.

8. A ceiling structure according to any one of the preceding claims, wherein insulating P.OPERUad389IOI Ispdoc27A)45 material is provided on the ceiling lining material.

9. A ceiling structure according to any one of the preceding claims, wherein the or each elongate support member is generally in a U-section.

A ceiling structure according to any one of the preceding claims, wherein the distal flange associated with each web projects outwardly away from the other web.

11. Use of an elongate support member as defined in claim 1 to support a ceiling lining material, wherein said lining material abuts and is fixedly secured to both distal flanges of the elongate support member to define a box section with the elongate support member.

12. A ceiling structure according to claim 1 substantially as hereinbefore described with reference to Figure 1 or 2.

13. Use according to claim 11 substantially as hereinbefore described. DATED this 2 7 t h day of April, 2005 Boral Australian Gypsum Limited by DAVIES COLLISON CAVE o* Patent Attorneys for the Applicant(s)