MATERIAL

Abstract

A material (1) for installation over a plurality of regularly spaced joists (12) to insulate a floor structure (10), the material (1) having a plurality of spaced apart sets of linearly arranged holes (3) extending across the width of the material (1), the holes (3) intended to overly the joists so that once the material (1) is in place, flooring material (90) can be adhered to the joists (12) through the holes (3), each set of linearly arranged holes (3) allowing access to 50 to 98 percent of the length of the joist (12) overlain by the set of holes (3).

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Australian Patent Application No. 2009905528, filed Nov. 11, 2009, which application is incorporated herein fully by this reference.

FIELD OF THE INVENTION

The present invention provides a material, methods of using the material, floor structures constructed using the material and tools used in the methods.

BACKGROUND TO THE INVENTION

With increased concern about the sustainability and environmental impact of energy consumption, there has been an increased focus on the energy efficiency of buildings such as houses in order to reduce their energy requirements. In PCT/AU2004/001498, the applicant proposed an insulation material that could be rapidly installed when the floor of a building is built on a frame structure.

The present application relates to developments of that material and techniques for installation of the material.

SUMMARY OF THE INVENTION

In a first aspect, there is provided a material for installation over a plurality of regularly spaced joists to insulate a floor structure, the material having a plurality of spaced apart sets of linearly arranged holes extending across the width of the material, the holes intended to overly the joists so that once the material is in place, flooring material can be adhered to the joists through the holes, each set of linearly arranged holes allowing access to 50 to 98 percent of the length of the joist overlain by the set of holes.

In an embodiment, each set of linearly arranged holes allows access to 65 to 90 percent of the length of the joist overlain by the set of holes.

In an embodiment, the spacing of the sets of holes from one another is greater than the spacing of the joists such that, in use, the material between adjacent joists hangs below the top of the joists to define an insulating air gap between the material and the flooring material once the flooring material is installed.

In an embodiment, the material further comprises fold lines either side of each set of holes to enable the material to be formed into a rectangular trough.

In an embodiment, the material further comprises indicia either side of each set of holes to indicate where the material should be folded to be formed into a rectangular trough.

In an embodiment, said material is heat reflective or has a heat reflective layer.

In an embodiment, the holes are circular or oval such that the regions around the holes are held taut to lie flat against the joists.

In an embodiment, the material is formed into a roll so that it can be rolled out across the joists during installation.

In an embodiment, the material further comprises indicia set in from the edge of the material indicating a desirable overlap with a neighbouring length of the material.

In a second aspect, there is provided a method of installing a floor on a plurality of regularly spaced joists, the method comprising:

• • locating a material having a plurality of spaced apart sets of linearly arranged holes extending across the width of the material such that respective ones of the sets of holes overly individual ones of the joists, each set of linearly arranged holes allowing access to 50 to 98 percent of the length of the joist overlain by the set of holes; and
  • adhering a flooring material to the joists with adhesive applied along the length of the joists where the holes overlie the joists.

In an embodiment, each set of linearly arranged holes allows access to 65 to 90 percent of the length of the joist overlain by the set of holes.

In an embodiment, the method further comprises attaching the material to the joists.

In an embodiment, the method comprises applying the adhesive in continuous beads extending along the length of the joists after locating the material in place.

In an embodiment, the spacing of the sets of holes from one another is greater than the spacing of the joists such that, in use, the material between adjacent joists hangs below the top of the joists to define an insulating air gap between the material and the flooring material once the flooring material is installed.

In an embodiment, the method comprises folding the material between each set of joists to define an air gap having a substantially rectangular cross-section.

In an embodiment, the method comprises folding the material along indicia indicating where the material should be folded.

In an embodiment, the method comprises folding the material with a tool having a substantially u-shaped cross-section by locating an open end of the tool over the material where it overlies the joists and pressing downwards to form the folds in the material.

In an embodiment, the method comprises fastening said flooring material to said joists with one or more fasteners.

In an embodiment, the method comprises rolling the material out across the joists.

In an embodiment, the method comprises mounting a roll holder to one end of the floor structure and placing a roll of the material on the roll holder for rolling out across the joists.

In a third aspect, there is provided a floor structure comprising:

• • a plurality of floor joists;
  • a layer of insulation material placed on top of the floor joist, the material having a plurality of spaced apart sets of linearly arranged holes extending across the width of the material such that respective ones of the sets of holes overly individual ones of the joists, each set of linearly arranged holes allowing access to 50 to 98 percent of the length of the joist overlain by the set of holes; and
  • flooring material placed on top of the insulation material and adhered to the joists with adhesive applied along the length of the joists where the holes overlie the joists.

In an embodiment, each set of linearly arranged holes allows access to 65 to 90 percent of the length of the joist overlain by the set of holes.

In an embodiment, the spacing of the sets of holes from one another is greater than the spacing of the joists such that, in use, the material between adjacent joists hangs below the top of the joists to define an insulating air gap between the material and the flooring material once the flooring material is installed.

In an embodiment, the material is folded to be formed into a rectangular trough below the flooring material.

In an embodiment, said material is heat reflective or has a heat reflective layer.

In an embodiment, the holes are circular or oval such that the regions of the material around the holes are held taut to lie flat against the joists.

In a fourth aspect, there is provided a tool for installing a material over a plurality regularly spaced joists to insulate a floor structure, the material having a plurality of spaced apart sets of linearly arranged holes extending across the width of the material, the spacing of the sets of holes from one another being greater than the spacing of the joists, the tool comprising:

• • a top wall; and
  • a pair of side walls extending from the top wall such that the tool has a generally u-shaped cross-section and an opening opposite the top wall, such that the tool can be located on top of the material where it overlies a joist and pressed downwardly with the side walls on opposite sides of the joist to fold the material against the sides of the joists.

In an embodiment, the tool is sized so as to be operable by hand.

In an embodiment, at the opening, each side wall terminates in a portion around which the material can be folded so as to form the material into a substantially rectangular trough.

In an embodiment, the portion of each side wall around which the material can be folded extends outwardly of the side wall.

In an embodiment, the tool comprises a triangular cut-out at least one end of the top wall, the apex of the cut-out evenly spaced from each side wall such that it corresponds to the centre of the joist.

In a fifth aspect, there is provided a roll holding apparatus for installing a roll of material over a plurality regularly spaced joists to insulate a floor structure, the roll holding apparatus comprising a pair of leg members, each having a hole therein for receiving a respective end of a spindle around which the material is rolled, each leg member having a foot adapted to be mounted to a beam of the floor structure such that the legs are supported in an upright configuration.

In an embodiment, each foot is of inverted u-shaped cross-section adapted to be placed over the beam.

In an embodiment, each leg member comprises a connection portion adapted to be connected to a connector whereby the leg members can be joined together.

In an embodiment, each connection portion is a sleeve adapted to receive a connector in the form of a rail.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described in relation to the following drawings in which:

FIG. 1 shows two rolls of material in accordance with an embodiment of the invention;

FIG. 2 shows a roll of material rolled out over a floor structure;

FIG. 3 is a detail view showing a roll of material being rolled out from a roll holding apparatus;

FIG. 4 shows a partially installed roll of material;

FIG. 5A shows detail of the partially installed material of FIG. 4;

FIG. 5B shows a tool for use in installation of the material;

FIG. 6 is a further view showing the tool in use;

FIG. 7 is a perspective view of the floor structure showing a roll of material having being installed prior to installation of flooring;

FIG. 8 is a detailed view of FIG. 7;

FIG. 9 shows a partially installed flooring material on the floor structure;

FIGS. 10A and 10B show holes of different shapes; and

FIGS. 11A and 11B show exemplary air gaps on joists of two different thicknesses.

DETAILED DESCRIPTION

FIG. 1, shows a pair of rolls 1 of material for installation over a plurality of regularly spaced joists of a floor structure in order to insulate the floor structure. Roll 1A is shown with the material rolled up around spindle 2 whereas roll 1B is almost completely rolled out and shows that the roll of material 1B comprises a plurality of sets of holes 3 which extend across the width of the material 1 and are spaced apart from one another. The holes 3 are arranged in lines and are intended to overlie the top of the joists of the floor structure.

In other embodiments, the material may be provided as flat sheets or concertina style sheets.

FIG. 2 shows a floor structure 10 in relation to which the material 1 is intended to be used. The floor structure 10 comprises a plurality of joists 12 which sit on bearers 11 to form a suspended floor. At each end of the structure 10 there is a double joist 13. FIG. 2 shows a roll of material mounted on a roll holding apparatus 20 (temporarily mounted to one of the double joists) and the material 1 rolled out to cover the floor structure. The material 1 is held on the roll holding apparatus 20 for ease of installation, however it will be apparent that it can be installed without the roll holding apparatus 20. The roll holding apparatus 20 has the advantage that it assists in keeping the material 1 correctly orientated relative to the floor structure 10.

FIG. 3 is a detailed view of the roll holding apparatus 20 from which it will be apparent that the roll holding apparatus has a pair of leg members 21A, 21B each of which has a hole 22 for receiving an end of the spindle 2. Hole 22 is an open hole through which the spindle extends but could alternatively be a blind hole. The roll can be installed on the roll holding apparatus by first placing one of the legs 21A in place on the double joist 13 at one end of the floor structure. Spindle 2 is fitted into a tube of roll 1 around which the material is wound. Spindle 2 is then fitted into the hole in the first leg member 21A before the second leg member 21B can be brought into place. Each leg member 21 has a foot formed by a U-shaped bracket attached to the foot of an L-shaped bracket that forms the rest of the leg. The foot 21A is designed to sit over the double joists 13 so that the leg will be supported in an upright manner.

In the embodiment, the leg members 21B are connected together to prevent them moving apart during installation of the material 1. It will be apparent that in other embodiments the leg members need not be joined together and could be, for example temporarily connected to the double joists 13. In this respect, each leg member 21 has a connecting portion in the form of a sleeve 24 which is adapted to receive rail 25. Each sleeve 24 has holes 26 therein through which some form of connector such as nail or a screw can be connected to the rail 25 to hold the rail in place with the legs at an appropriate separation. It will be appreciated the rail 25 can subsequently be removed by undoing the connector. The rail also makes it easier to move the roll holding apparatus to the next position at which material is to be rolled out.

FIG. 4 shows the material partially installed. Persons skilled in the art will appreciate that the end of the material 4 does not have holes as it can be affixed to the joist side so that it will not interfere in the adhesive operation which will be described in further detail below. The material 1 is typically attached to the joist by applying staples in the region generally indicated as 5 in FIG. 5A.

In an embodiment, a folding tool 30 is used to fold the material over the joists to form rectangular troughs 40 in the material where the material hangs below the top of the joists. Accordingly it will be appreciated that the sets of holes 3 are spaced further apart than the anticipated spacing of the joists. In this respect, in a typical floor structure joist centres are regularly spaced at 450 mm. In other structures though the spacing may vary, for example, it may be a 600 mm spacing between joists centres. The folding tool is used by pushing it down where the material overlies the joists and moving it from one end of the joist to the other along the material so that the holes 3 are aligned with the middle of the top of the joist 12.

FIGS. 5A and 5B show the tool 30 in more detail, in particular that it has top wall 31 and a pair of parallel side walls 33A, 33B such that the tool 30 has a generally U-shaped cross section (inverted in the view of FIG. 5B). The side walls define between them an opening 34 which is placed over the material where it overlies the joist. Each end of the top wall 31 has a triangular cut-out, the apex 36A,36B of which corresponds to the centre of the top wall 31. This apex 36A, 36B allows the material to be aligned with the centre of the holes corresponding the apex to ensure correct alignment of the holes with the joists as it is moved into place. Persons skilled in the art will appreciate that other techniques can be used to indicate the centre of the tool, such as other cut-out shapes, a sticker, a formed line an etched line etc.

Tool 30 has a series of perforations 32 where the top wall 30 meets the side walls 33. These perforations enable the tool to be supplied flat before subsequently being bent into the configuration shown in FIG. 5B. The end of each side wall 33 is folded in a circular form back toward the side walls to form two folding assisting portions 35A,35B extending outwardly of the opening 34 around which the material can be folded without being damaged. FIG. 6 shows the tool 30 in position over one of the joists. In an embodiment, the length of the side walls 33 can be chosen to correspond to the desired depth of the fold.

FIG. 7 shows the floor structure once a roll of material 1 has been rolled out over all of the joists to form a plurality of rectangular troughs with the holes sitting on top of each of the joists. At this stage, the material 1 will have been attached to each of the joists so that the material 1 is firmly held in place. The next stage of the operation is to apply adhesive material where flooring is to overlie the joists 12 and the material 1. FIG. 7 shows that beads of adhesive 71 have been applied to two end joists 13 and the immediately inward joists 12. FIG. 8 shows this in further detail and shows that a pair of beads of adhesive 71A have been applied along the double end joists 13 and a single bead of adhesive 71B has been applied along the top of joists 12. It will be apparent from FIG. 8 that each bead 71 has been applied continuously where it is expected that the flooring material will overlie the joists. The holes 3 are sized such that sufficient of this adhesive is between the flooring material and the joists 12.

FIG. 9 shows that the flooring between material 90A has been applied across some of the joists and a further piece of flooring material 90B is to be installed over joists also having beads of adhesive applied thereto. From FIG. 9 it will be apparent that the flooring material and the material 1 form substantially rectangular shaped air gaps 91. These air gaps 91 can be closed at each end by an additional layer of material or by having a portion of material extend beyond the last bearer and folded upward to close the gap.

FIGS. 10A to 10E show some possible alternative hole shapes. In this respect, it is preferred that the holes allow 50% to 98% of a continuous adhesive bead or put another way, each set of holes allows access to 50% to 98% of the length of the joist which is overlain by the set of holes. More preferably the holes allow access to at least 65% of the length of the joist and even more preferably at least 75%. More preferably, the holes allow access to no more than 90% to reduce the prospect of holes tearing. Thus in some embodiments, the holes may allow access to 65-98%, 75-98%, 65-90%, or 75-90%. In this respect, it will be appreciated that the maximum achievable length of continuous bead will depend on the material used and the material's propensity to tear. For example, a metallic material is suited to high values of continuous bead.

The ovals shown in FIG. 10A have in practice a length of 65 mm and a width of 30 mm allowing an 86.66% continuous adhesive bead. In the example of FIG. 10A, there would be 12 holes for a 900 mm wide floor panel. FIG. 10B shows an example using smaller oval holes of 40 mm in length and 25 mm in width. There are 12 holes in this example for a 900 mm wide floor panel allowing 53.33% of continuous adhesive bead. For the same 900 mm wide floor panel 25 square holes will be used as shown in FIG. 10C of the dimensions 25 mm by 25 mm providing 69.44% continuous adhesive bead. Similarly 22 mm round holes shown in FIG. 10D would provide a 73.3% continuous bead and 15 mm bi-lobed round crossover holes having a length of 45 mm in width and 30 mm would provide about 75% continuous bead. The actual size of holes chosen will depend on the strength of the material and the extent to which the sections in between the holes are capable of holding the material together without tearing. Of the hole shapes, the circular or oval hole shapes shown in FIGS. 10A, 10B and 10D are preferred because they tend to keep the material taut around the hole because the continuous shapes of the hole mean that tension around the perimeter is substantially equal. As a result, the material 1 surrounding the holes will tend to lie flat against as it is held taut by the shape of the holes. This reduces the prospect of air gaps developing between the material and the holes. It also reduces the prospects of the material tearing around the hole or being torn as there are no clear weak spots.

FIGS. 11A and 11B illustrate the possibility that different spacings can be used between rows of holes to provide air gaps of different sizes in order to meet the thermal requirements of a floor structure. FIG. 11A shows these schematically in relation to joists of 35 mm thickness whereas FIG. 11B shows these in respect of joists 12B of 45 mm thickness. From this it will be apparent that the thickness of the joists does not affect the size of the spacing because the overall distance will still be the same. However, the bends in the material will be at different locations. The spacing of the hole centres can be determined by adding the joist spacing to twice the required thermal gap and a material thickness and bend radiance of allowance, for example half the material thickness times the number of bends.

Accordingly, for a relatively thin material, for example 1 mm or 2 mm to achieve a 90 mm thermal gap between the material 1 and flooring material 90, a 626 mm spacing is required between the centres of the holes. In this example where the joists are 45 mm thick as shown in FIG. 11B the distance between the bends will be a approximately 403 mm. Air gap 54 shown in FIG. 11B and the corresponding air gap 50 shown in FIG. 11A are provided by the same hole spacing but the distance between the bend centres at the bottom of the joists will be 413 mm in FIG. 11A. Similarly, a 67.5 mm thermal gap can be provided by having a hole spacing of 561 mm as is shown by air gaps 55, 51; a 45 mm thermal gap 52, 56, can be provided by a spacing of 536 mm; and a 22.5 mm thermal gap can be provided by a spacing of 491 mm. Accordingly, it will be appreciated that the holes can be any distance apart but this distance determines the depth of the troughs which are formed. By controlling the depth of the trough the thermal efficiency can be controlled for the selected material.

While it is preferred that the material is formed of a sheet of heat reflecting material, it will be appreciated that other substrates may be used while obtaining some of the benefits. It is also possible, that more than one substrate can be laid (one on top of the other) to create additional thermal (and reflective) gaps. In another embodiment, the material itself can have plural layers, for example two or more layers such that, for example, one or more layers may be formed of reflective material. Other materials which may provide some or all advantages include multi-layer laminates, air bubble material, expanded foam etc.

In addition to the above, the material may incorporate fold lines, for example, preformed as creases in the material or by small perforations in the surface of the material to aid folding in situ. Alternatively, the positions at which folds are to be made may be indicated by indicia such as printed lines on the material of depth markers. It will be appreciated that the hand tool 30 may eliminate the need for fold depth markers and similarly, physical fold lines may prevent the need for the hand tool.

Indicia can also be used to indicate overlap distance for adjacent sheets of material, for example, line 50 mm and/or 150 mm in from the edges (running parallel with the edge).

Advantages of embodiments of the invention include that:

• • it is quick to install;
  • it is prefabricated with holes;
  • holes can be put in most materials suitable for the purpose;
  • the holes can be manufactured at the desired spacing;
  • folding the material means that a small number of staples can be used to secure the material to the joists;
  • the hole dimensions allow for sufficient glue to be applied to the joist;
  • circular or oval shapes hold the material taut over the joists; and
  • fold lines, physical folds or the handle tool assist in producing rectangular air gaps to maximise the effect of air gap installation;
  • where fold lines/perforations are used this may eliminate the need to fasten the material to the joists as the material will keep its shape due to the fold lines/perforations.

A person skilled in the art will appreciate that numerous other variations fall within the scope of the invention described herein. For example, while the invention has been described in relation to a wooden structure for supporting flooring material, the invention is equally applicable to situations where the frame is metal.

Further, while the example of fasteners used to attach the substrate to the joists and the flooring to the joists are given above a person skilled in the art will appreciate the number of different fasteners can be used. For example, if a metal floor substrate is used, fasteners in the form of screws would be more appropriate than nails. Further, it may be possible to attach the substrate to the joist using an adhesive rather than staples depending on the embodiment.

Persons skilled in the art will also appreciate that joists and bearers could run in different directions in different areas of the floor structure.

It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art in any country.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Claims

1. A material for installation over a plurality of regularly spaced joists to insulate a floor structure, the material having a plurality of spaced apart sets of linearly arranged holes extending across the width of the material, the holes intended to overly the joists so that once the material is in place, flooring material can be adhered to the joists through the holes, each set of linearly arranged holes allowing access to 50 to 98 percent of the length of the joist overlain by the set of holes.

2. A material as claimed in claim 1, wherein each set of linearly arranged holes allows access to 65 to 90 percent of the length of the joist overlain by the set of holes.

3. A material as claimed in claim 1, wherein the spacing of the sets of holes from one another is greater than the spacing of the joists such that, in use, the material between adjacent joists hangs below the top of the joists to define an insulating air gap between the material and the flooring material once the flooring material is installed.

4. A material as claimed in claim 3, further comprising fold lines either side of each set of holes to enable the material to be formed into a rectangular trough.

5. A material as claimed in claim 3, further comprising indicia either side of each set of holes to indicate where the material should be folded to be formed into a rectangular trough.

6. A material as claimed in claim 1, wherein said material is heat reflective or has a heat reflective layer.

7. A material as claimed in claim 1, wherein the holes are circular or oval such that the regions around the holes are held taut to lie flat against the joists.

8. A material as claimed claim 1, formed into a roll so that it can be rolled out across the joists during installation.

9. A material as claimed in claim 1, further comprising indicia set in from the edge of the material indicating a desirable overlap with a neighboring length of the material.

10. A method of installing a floor on a plurality of regularly spaced joists, the method comprising: locating a material having a plurality of spaced apart sets of linearly arranged holes extending across the width of the material such that respective ones of the sets of holes overly individual ones of the joists, each set of linearly arranged holes allowing access to 50 to 98 percent of the length of the joist overlain by the set of holes; andadhering a flooring material to the joists with adhesive applied along the length of the joists where the holes overlie the joists.

11. A method as claimed in claim 10, wherein each set of linearly arranged holes allows access to 65 to 90 percent of the length of the joist overlain by the set of holes.

12. A method as claimed in claim 10, further comprising attaching the material to the joists.

13. A method as claimed in claim 10, comprising applying the adhesive in continuous beads extending along the length of the joists after locating the material in place.

14. A method as claimed in claim 10, wherein the spacing of the sets of holes from one another is greater than the spacing of the joists such that, in use, the material between adjacent joists hangs below the top of the joists to define an insulating air gap between the material and the flooring material once the flooring material is installed.

15. A method as claimed in claim 14, comprising folding the material between each set of joists to define an air gap having a substantially rectangular cross-section.

16. A method as claimed in claim 15, comprising folding the material along indicia indicating where the material should be folded.

17. A method as claimed in claim 15, comprising folding the material with a tool having a substantially u-shaped cross-section by locating an open end of the tool over the material where it overlies the joists and pressing downwards to form the folds in the material.

18. A method as claimed in claim 10, further comprising fastening said flooring material to said joists with one or more fasteners.

19. A method as claimed in claim 10, comprising rolling the material out across the joists.

20. A method as claimed in claim 19 comprising mounting a roll holder to one end of the floor structure and placing a roll of the material on the roll holder for rolling out across the joists.

21. A floor structure comprising: a plurality of floor joists;a layer of insulation material placed on top of the floor joist, the material having a plurality of spaced apart sets of linearly arranged holes extending across the width of the material such that respective ones of the sets of holes overly individual ones of the joists, each set of linearly arranged holes allowing access to 50 to 98 percent of the length of the joist overlain by the set of holes; andflooring material placed on top of the insulation material and adhered to the joists with adhesive applied along the length of the joists where the holes overlie the joists.

22. A floor structure as claimed in claim 21, wherein each set of linearly arranged holes allows access to 65 to 90 percent of the length of the joist overlain by the set of holes.

23. A floor structure as claimed in claim 21, wherein the spacing of the sets of holes from one another is greater than the spacing of the joists such that, in use, the material between adjacent joists hangs below the top of the joists to define an insulating air gap between the material and the flooring material once the flooring material is installed.

24. A floor structure as claimed in claim 23, wherein the material is folded to be formed into a rectangular trough below the flooring material.

25. A floor structure as claimed in claim 21, wherein said material is heat reflective or has a heat reflective layer.

26. A floor structure as claimed in claim 21, wherein the holes are circular or oval such that the regions of the material around the holes are held taut to lie flat against the joists.

27. A tool for installing a material over a plurality regularly spaced joists to insulate a floor structure, the material having a plurality of spaced apart sets of linearly arranged holes extending across the width of the material, the spacing of the sets of holes from one another being greater than the spacing of the joists, the tool comprising: a top wall; anda pair of side walls extending from the top wall such that the tool has a generally u-shaped cross-section and an opening opposite the top wall, such that the tool can be located on top of the material where it overlies a joist and pressed downwardly with the side walls on opposite sides of the joist to fold the material against the sides of the joists.

28. A tool as claimed in claim 27, sized so as to be operable by hand.

29. A tool as claimed in claim 27, wherein at the opening, each side wall terminates in a portion around which the material can be folded so as to form the material into a substantially rectangular trough.

30. A tool as claimed in claim 29, the portion of each side wall around which the material can be folded extends outwardly of the side wall.

31. A tool as claimed in claim 27, comprising a triangular cut-out at least one end of the top wall, the apex of the cut-out evenly spaced from each side wall such that it corresponds to the centre of the joist.

32. A roll holding apparatus for installing a roll of material over a plurality regularly spaced joists to insulate a floor structure, the roll holding apparatus comprising a pair of leg members, each having a hole therein for receiving a respective end of a spindle around which the material is rolled, each leg member having a foot adapted to be mounted to a beam of the floor structure such that the legs are supported in an upright configuration.

33. A roll holding apparatus as claimed in claim 32, wherein each foot is of inverted u-shaped cross-section adapted to be placed over the beam.

34. A roll holding apparatus as claimed in claim 32, wherein each leg member comprises a connection portion adapted to be connected to a connector whereby the leg members can be joined together.

35. A roll holding apparatus as claimed in claim 34, wherein each connection portion is a sleeve adapted to receive a connector in the form of a rail.