Background of the Invention

[0001] The present invention generally relates to building materials, and particularly, but not limited to, panels, beams and/or planks for use in floors, walls, roofs and/or other locations. The present invention also generally relates to methods of manufacturing such building materials.

Description of the Prior Art

[0002] Recent events resulting in supply chain disruptions and increases in demand for building products have contributed to cases of shortages in basic materials, such as planks, beams and panels, for example. Long term trends away from logging for environmental and sustainability reasons have also contributed to reducing supply and increasing prices for timber products.

[0003] It is therefore desirable to remove or at least reduce the demand for timber products in the building industry. Costs also tend to be a very important consideration in the building industry, so doing so in a cost-effective manner may also be advantageous.

[0004] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Summary of the Present Invention

[0005] According to one broad aspect of the invention, there is provided a plank for use in constructing a floor, the plank comprising: a core with a rectangular cross section; at least one stringer forming part of the core and extending in a longitudinal direction along the plank; and an outer skin substantially covering at least a top surface, a bottom surface, and two side surfaces of the core. [0006] In an embodiment, the stringer forms a comer of the core where the top surface meets one of the side surfaces.

[0007] In an embodiment, stringers form both of the comers where the top surface meets the side surfaces.

[0008] In an embodiment, stringers form all four comers where the top surface meets the side surfaces and where the bottom surface meets the side surfaces.

[0009] In an embodiment, an additional stringer is embedded substantially centrally in the top surface.

[0010] In an embodiment, the core is formed from at least one of: expanded polystyrene (EPS) foam; fire retardant EPS; plant-based EPS; cellulose nanocrystal based foam; cork; and, compressed plant material.

[0011] In an embodiment, the skin is formed from at least one of: sheet metal; and, composite material.

[0012] In an embodiment, the skin covering at least the top surface is textured and/or has an imitation wood appearance.

[0013] In an embodiment, the stringer is formed from at least one of: wood; plastic; aluminium; steel; grout; and, concrete.

[0014] In an embodiment, the skin is formed by a C shaped section covering each of the side surfaces and a flat sheet covering each of the top surface and the bottom surface.

[0015] In an embodiment, the skin is formed by a single sheet being folded about the top surface, the bottom surface, and the side surfaces, so that a portion of the sheet overlaps itself.

[0016] In an embodiment, the skin is formed by a flat sheet covering the top surface and a folded sheet covering the side surfaces, the bottom surface, and overlapping with at least a portion of the flat sheet proximal to edges of the top surface. [0017] In an embodiment, the skin is formed by a first folded sheet being U shaped and covering the top surface and the side surfaces, and a second folded sheet being U shaped and covering the bottom surface and the side surfaces.

[0018] In an embodiment, the plank further comprises an end closer.

[0019] In an embodiment, the skin is glued to the core.

[0020] In an embodiment, the skin is fixed to the core and/or to overlapping portions of the skin using fasteners.

[0021] In an embodiment, dimensions of the plank are at least one of: a width of the plank is at least one of: 600mm; between 500mm and 700mm; greater than 400mm; and, greater than 500% of a depth of the plank; a depth of the plank is at least one of: 100mm; between 50mm and 200mm; greater than 50mm; and, less than 20% of a width of the plank; and, a length of the plank is at least one of: 6000mm; greater than 5000mm; and, greater than 10 times a width of the plank.

[0022] According to another broad aspect of the invention, there is provided a beam for use in constructing a building, the beam comprising: a core with a rectangular cross section; an outer skin substantially covering at least a bottom surface, and two side surfaces of the core; and, at least one stringer forming part of the core and extending in a longitudinal direction along the beam.

[0023] In an embodiment, the skin substantially covers a top surface of the core.

[0024] In an embodiment, a top surface of the core is exposed.

[0025] In an embodiment, the stringer forms the top surface of the core.

[0026] In an embodiment, stringers form both the top surface and the bottom surface.

[0027] In an embodiment, an additional stringer extends between the stringer at the top surface and the stringer at the bottom surface, such that the stringers together form a single stringer with an I-shaped cross section. [0028] In an embodiment, the core is formed from at least one of: expanded polystyrene (EPS) foam; fire retardant EPS; plant-based EPS; cellulose nanocrystal based foam; cork; and, compressed plant material.

[0029] In an embodiment, the skin is formed from at least one of: sheet metal; and, composite material.

[0030] In an embodiment, the stringer is formed from at least one of: wood; plastic; aluminium; steel; grout; and, concrete.

[0031] In an embodiment, the skin is formed by a C shaped section covering each of the top surface and bottom surface, and a flat sheet covering each of the side surfaces.

[0032] In an embodiment, the skin is formed by a single sheet being folded about the top surface, the bottom surface, and the side surfaces, so that a portion of the sheet overlaps itself.

[0033] In an embodiment, the skin is formed by a flat sheet covering the top surface and a folded sheet covering the side surfaces, the bottom surface, and overlapping with at least a portion of the flat sheet proximal to edges of the top surface.

[0034] In an embodiment, the skin is formed by a first folded sheet being U shaped and covering the top surface and the side surfaces, and a second folded sheet being U shaped and covering the bottom surface and the side surfaces.

[0035] In an embodiment, the skin is formed by a folded sheet being U shaped and covering the bottom surface and the side surfaces.

[0036] In an embodiment, the skin includes inwardly turned flanges along upper edges of the side surfaces.

[0037] In an embodiment, the beam further comprises an end closer.

[0038] In an embodiment, the skin is glued to the core.

[0039] In an embodiment, the skin is fixed to the core and/or to overlapping portions of the skin using fasteners. [0040] In an embodiment, dimensions of the beam are at least one of: a width of the beam is at least one of: 90mm; between 50mm and 100mm; greater than 100mm; and, approximately 30% of a depth of the beam; a depth of the beam is at least one of: 300mm; between 200mm and 400mm; greater than 300mm; and, greater than 300% of a width of the beam; and, a length of the beam is at least one of: 6000mm; greater than 6000mm; and, greater than 10 times a depth of the beam.

[0041] In an embodiment, the core includes one or more infdls formed from a lightweight material, and wherein at least one stringer is formed from grout that fills voids between the infills and the skin.

[0042] In an embodiment, the core includes reinforcements positioned in the voids such that the reinforcements are embedded in the grout that fills the voids.

[0043] In an embodiment, the reinforcements include at least one of: plates; extruded sections; bars; rods; and, ligatures.

[0044] In an embodiment, the beam includes inserts that are embedded in the grout and allow the beam to be connected to another structural element.

[0045] According to another broad aspect of the invention, there is provided a frame for a doorway or similar opening in a building, wherein at least the lintel is formed using a beam substantially as described herein.

[0046] According to another broad aspect of the invention, there is provided a panel for use in constructing a building, the panel comprising: a core with a rectangular cross section; an outer skin substantially covering at least a top surface, a bottom surface, and two side surfaces.

[0047] In an embodiment, the panel further comprises at least one stringer forming part of the core and extending in a longitudinal direction along the panel.

[0048] In an embodiment, the core is formed from at least one of: expanded polystyrene (EPS) foam; fire retardant EPS; plant-based EPS; cellulose nanocrystal based foam; cork; and, compressed plant material. [0049] In an embodiment, the skin is formed from at least one of: sheet metal; and, composite material.

[0050] In an embodiment, the stringer is formed from at least one of: wood; plastic; aluminium; steel; grout; and, concrete.

[0051] In an embodiment, the skin is formed by a C shaped section covering each of the side surfaces and a flat sheet covering each of the top surface and the bottom surface.

[0052] In an embodiment, the skin is formed by a single sheet being folded about the top surface, the bottom surface, and the side surfaces, so that a portion of the sheet overlaps itself.

[0053] In an embodiment, the skin is formed by a flat sheet covering the top surface and a folded sheet covering the side surfaces, the bottom surface, and overlapping with at least a portion of the flat sheet proximal to edges of the top surface.

[0054] In an embodiment, the skin is formed by a first folded sheet being U shaped and covering the top surface and the side surfaces, and a second folded sheet being U shaped and covering the bottom surface and the side surfaces.

[0055] In an embodiment, the skin is glued to the core.

[0056] In an embodiment, the skin is fixed to the core and/or to overlapping portions of the skin using fasteners.

[0057] According to another broad aspect of the invention, there is provided a method of constructing a floor, the floor comprising a plurality of planks substantially as defined herein, wherein the planks are laid so that the side surfaces abut one another.

[0058] In an embodiment, the side surfaces that abut one another are held in place using double sided tape.

[0059] According to another broad aspect of the invention, there is provided a method of constructing a floor, the floor comprising a plurality of planks substantially as defined herein, wherein the planks are laid so that the side surfaces are parallel to one another and a distance between adjacent side surfaces is at least one of: approximately 400mm; between 350mm and 450mm; greater than 300mm; greaterthan 200mm; and, greater than 50% of a width of a panel.

[0060] In an embodiment, the planks have flooring sections affixed and additional flooring sections are placed in and span the distances between adjacent planks.

[0061] In an embodiment, the planks have flooring sections affixed and the flooring sections overhang at least one side of the plank so as to extend across the distance between adjacent planks.

[0062] In an embodiment, flooring is fixed to the planks using fasteners inserted into or through at least some of the stringers.

[0063] In an embodiment, the planks are supported by at least one beam substantially as defined herein.

[0064] According to another broad aspect of the invention, there is provided formwork for use in constructing a concrete slab, the formwork comprising one or more planks substantially as defined herein, and/or one or more beams substantially as defined herein.

[0065] It will be appreciated that the broad forms of the invention and their respective features can be used in conjunction and/or independently, and reference to separate broad forms is not intended to be limiting. Furthermore, it will be appreciated that features of the method can be performed using the system or apparatus and that features of the system or apparatus can be implemented using the method.

Brief Description of the Drawings

[0066] Various examples and embodiments of the present invention will now be described with reference to the accompanying drawings, in which: -

[0067] Figure 1 is an oblique view of a plank according to an embodiment of the invention;

[0068] Figure 2 is a cross sectional end view of the plank from Figure 1;

[0069] Figure 3 is a cross sectional end view of another embodiment of the plank; [0070] Figure 4 is a cross sectional end view of another embodiment of the plank;

[0071] Figure 5 is a cross sectional end view of another embodiment of the plank;

[0072] Figure 6 is a cross sectional end view of another embodiment of the plank;

[0073] Figure 7 is an isometric view of another embodiment of the plank, with the skin and a top surface removed for illustrative purposes;

[0074] Figure 8 is a cross sectional end view of another embodiment of the plank;

[0075] Figure 9 is an exploded cross sectional end view of another embodiment of the plank;

[0076] Figure 10 is an exploded cross sectional end view of another embodiment of the plank;

[0077] Figure 11 is an exploded cross sectional end view of another embodiment of the plank;

[0078] Figure 12 is an exploded cross sectional end view of another embodiment of the plank;

[0079] Figure 13 is an exploded isometric view of the plank from Figure 9;

[0080] Figure 14 is an isometric view of the plank from Figure 13;

[0081] Figure 15 is an exploded isometric view of the plank from Figure 11;

[0082] Figure 16 is an isometric view of the plank from Figure 15;

[0083] Figure 17 is a floor layout according to an embodiment of the invention;

[0084] Figure 18 is an alternative floor layout according to another embodiment of the invention;

[0085] Figure 19 is an oblique view of a beam according to an embodiment of the invention;

[0086] Figure 20 is a cross sectional end view of the beam from Figure 10;

[0087] Figure 21 is a cross sectional end view of another embodiment of the beam;

[0088] Figure 22 is a cross sectional end view of another embodiment of the beam; [0089] Figure 23 is an exploded cross sectional end view of another embodiment of the beam;

[0090] Figure 24 is a cross sectional end view of another embodiment of the beam;

[0091] Figure 25 is a cross sectional side view of the beam from Figure 24;

[0092] Figure 26 is a cross sectional end view of another embodiment of the beam;

[0093] Figure 27 is a cross sectional side view of the beam from Figure 26;

[0094] Figure 28 is a cross sectional end view of the skin of another embodiment of the beam;

[0095] Figure 29 is a cross sectional end view of the skin of another embodiment of the beam;

[0096] Figure 30A is a cross sectional end view of another embodiment of the beam;

[0097] Figure 30B is a perspective view of the beam from Figure 30A;

[0098] Figure 30C is a perspective view of reinforcements of the beam from Figure 30A;

[0099] Figure 30D is a perspective view of reinforcements, infills and inserts of the beam from Figure 30A;

[0100] Figure 30E is a perspective view of an end cap, reinforcements, infills and inserts of the beam from Figure 30A;

[0101] Figure 30F is a side view of the beam from Figure 30A;

[0102] Figure 30G is a side view of reinforcements, infills and inserts of the beam from Figure 30A;

[0103] Figure 30H is a side view of end caps, reinforcements and inserts of the beam from Figure 30A;

[0104] Figure 301 is a side view of Detail A from Figure 30G;

[0105] Figure 30J is a top view of the beam from Figure 30A; [0106] Figure 31 A is a perspective view of a connection between two of the beams from Figure 30A;

[0107] Figure 3 IB is a top view of a connection between two of the beams from Figure 30A;

[0108] Figure 32A is a cross sectional end view of another embodiment of the beam;

[0109] Figure 32B is a perspective view of reinforcements, infills and inserts of the beam from Figure 32A;

[0110] Figure 32C is a top view of the beam from Figure 32A;

[0111] Figure 33A is a cross sectional end view of another embodiment of the beam;

[0112] Figure 33B is a perspective view of reinforcements, infills and inserts of the beam from Figure 33 A; and,

[0113] Figure 33C is a top view of the beam from Figure 33A.

Detailed Description of the Preferred Embodiments

[0114] The following modes, given by way of example only, are described in order to provide a more precise understanding of the subject matter of a preferred embodiment or embodiments.

[0115] In the Figures, incorporated to illustrate features of an example embodiment, like reference numerals are used to identify like parts throughout the Figures.

[0116] An example of a plank according to the invention that is suitable for use as a building material will now be described. In this example, the plank has a core that has a rectangular cross section. At least one stringer forms part of the core and extends in a longitudinal direction along the plank. This core is covered with an outer skin that is attached directly to the core and covers at least atop surface, a bottom surface, and two side surfaces of the core.

[0117] The plank constructed in this way may be advantageous because much or even all of the material may be something other than timber. While timber may have better properties on its own than the individual materials used in the plank described here, the combination of features of the plank can allow it to have similar or even improved properties over a plank made solely from timber.

[0118] A number of other features will now be described, which may be optional or advantageous aspects of some example embodiments.

[0119] In one preferred embodiment, the core may be formed from expanded polystyrene (EPS) foam. EPS is a lightweight cellular plastic material, typically formed by packing together small hollow spherical balls of polystyrene. This construction results in a closed cellular form that gives EPS some advantageous properties, such as very low weight and high thermal insulation. EPS is cheap to manufacture and is also an inert material that does not rot or corrode and does not attract pests, such as rats or termites.

[0120] In some optional embodiments, the core may be formed from fire retardant EPS, plantbased EPS, cellulose nanocrystal based foam, or some other suitable related material with similarly high strength to weight ratio. Other suitable core materials include cork or compressed plant material.

[0121] In another preferred embodiment, the skin may be formed from sheet metal. For example, this may be coated or uncoated steel sheet in any suitable thickness, such as but not limited to galvanised steel or commercially available products sold under brands such as Zincalume® or Colorbond®, or similar alternatives. In one particular embodiment, the skin may be formed from Colorbond® steel of 0.55mm base metal thickness (BMT). In another particular embodiment, the skin may be formed from stainless steel.

[0122] In some alternative embodiments, the skin may be formed from a non-metal sheet material. For example, a composite material such as fibreglass or carbon fibre may be used. In another optional embodiment, the skin covering at least the top surface may be textured and/or may have an imitation wood appearance. This allows the planks to be used in the construction of a floor, for example, without the need for any other covering material at all.

[0123] In another preferred embodiment, the stringer is formed from wood. This may not only increase the strength of the plank, but also has the advantage that it provides a base into which fasteners can be secured, such as nails or screws. EPS has very limited ability to secure such fasteners, and securing the plank using only the skin may not provide sufficient strength. Therefore, providing stringers made from a material such as wood in locations where fasteners are likely to be required is particularly advantageous.

[0124] In some alternative embodiments, however, the stringers may be formed from some other suitable material, such as but not limited to, plastic, aluminium, or steel.

[0125] In some implementations, the stringers may be formed from a cement-based grout or concrete (henceforth referred to under the term "grout"). The grout can optionally include additives such as synthetic or metal fibres. In one example, the core may be formed with a cross section shape that does not fill the rectangular cross section of the plank, so as to define voids between the skin and the core that extend in a longitudinal direction along the plank. The voids may then be filled by pouring the grout in a fluid form into the voids, with the skin acting as a formwork. The grout may then be allowed to cure and set hard, such that the grout will effectively provide the stringers of the plank. Detailed examples using this technique will be described in due course.

[0126] The plank may also include internal reinforcement elements, in addition to the stringers, such as steel reinforcement bars embedded within the core, or other suitable reinforcement materials such as fibre glass or carbon fibre elements. The reinforcement elements will usually extend in a longitudinal direction along the plank, but may also extend across the width of the plank, or even diagonally.

[0127] Various embodiments may use different methods of wrapping the skin about the core. In one example, the skin may be formed by a C shaped section covering each of the side surfaces and a flat sheet covering each of the top surface and the bottom surface. This may result in overlapping portions of the skin near the edges of the top and bottom surfaces.

[0128] In another example, the skin may be formed by a single sheet being folded about the entire plank. That is, a single sheet is folded about the top surface, the bottom surface, and the side surfaces, so that a portion of the sheet overlaps itself. [0129] In another example, the skin is formed by a flat sheet covering the top surface and a separate folded sheet in a U shape covering the side surfaces, the bottom surface, and overlapping with at least a portion of the flat sheet proximal to edges of the top surface.

[0130] In another example, the skin may be formed by a first folded sheet being U shaped and covering the top surface and the side surfaces, and a second folded sheet being U shaped and covering the bottom surface and the side surfaces.

[0131] Typically, the skin can be glued to the core. Additionally or alternatively, overlapping portions of the skin may be secured to one another using fasteners, such as rivets for example. In yet another optional example, the skin may be fastened to one or more stringers.

[0132] The above options for the different methods of forming the skin may also allow the option of different portions of the skin having different thickness. For example, only the top surface may be thicker or a different material when this is a separate piece to the remainder of the skin. Similarly, the portions covering the side surfaces may be a different thickness where the method allows.

[0133] Various embodiments may use different layouts for the location of the stringer(s). For example, the stringer may form a comer of the core where the top surface meets one of the side surfaces. In another example, stringers may form both of the comers where the top surface meets the side surfaces, and/or stringers form all four comers where the top surface meets the side surfaces and where the bottom surface meets the side surfaces.

[0134] In one alternative embodiment, an additional stringer is embedded substantially centrally in the top surface. This stringer may be made from the same or different material to the other stringer(s).

[0135] In one embodiment, the plank may also have an end closer. That is, at one or both ends of the plank the core may be made entirely from the same material as the stringers, or some other material that is different to the remainder of the core. The end closer may still have one or more stringers extending through, or may entirely replace the core at this end location.

[0136] The plank may be formed with any dimensions suitable for a particular task. One preferred embodiment could have a width of 600mm, depth of 100mm, and length of 6000mm. [0137] In other examples, the width may be varied to some other desirable dimension, such as but not limited to between 500mm and 700mm, greater than 400mm, or greater than 500% of a depth of the plank. In other examples, the depth may be varied to some other desirable dimension, such as but not limited to between 50mm and 200mm, greater than 50mm, or less than 20% of a width of the plank. In other examples, the length may be varied to some other desirable dimension, such as but not limited to greater than 5000mm, or greater than 10 times a width of the plank.

[0138] An example of a beam according to the invention that is suitable for use as a building material will now be described. In this example, the beam has a core with a rectangular cross section. At least one stringer forms part of the core and extends in a longitudinal direction along the beam. This core is covered by an outer skin that substantially covers at least a bottom surface, and two side surfaces of the core.

[0139] Typically, beams and planks may be distinguished from one another by the relative widths and depths of their rectangular cross sections. In particular, beams will generally have a rectangular cross section with its width being substantially less than its depth, whereas planks will generally have a cross section with its width being substantially greater than its depth.

[0140] In some embodiments of the beam, the outer skin substantially covers a top surface of the core, as in the examples of the panel described above. However, in some alternative embodiments of the beam, the top surface of the core can be exposed, or in other words not covered by the outer skin. Leaving the top surface of the core exposed may be acceptable in a range of typical beam installation scenarios, and can simplify construction of the beam, particularly where grout is used to form the stringers, as discussed in some of the specific examples in due course.

[0141] For instance, in some embodiments of the beam, the core may include one or more infills formed from a lightweight material. Stringers may be formed from grout that fills voids between the infills and the skin. It will be appreciated that this enables the beam to be constructed by pouring the grout in a liquid form into the voids and allowing it to cure to therefore effectively form rigid stringers extending along the beam. [0142] In some embodiments, the core may include reinforcements positioned in the voids such that the reinforcements are embedded in the grout that fills the voids. For example, the reinforcements include at least one of: plates; extruded sections; bars; rods; and, ligatures. In some implementations, the beam may include inserts that are embedded in the grout and allow the beam to be connected to another structural element, such as another beam.

[0143] The beam may also include internal reinforcement members similar to those described above for the plank. These reinforcements may be especially beneficial for increasing the structural load bearing capacity of the beam.

[0144] In any event, these different embodiments of the beam have many of the same advantages as the plank described previously, and some optional forms of the beam may also have many of the same features. A number of these other features will now be described, which may be optional or advantageous aspects of some example embodiments.

[0145] In one embodiment, the stringer may form the top surface of the core, while in another embodiment, stringers may form both the top surface and the bottom surface. These stringers may improve the strength of the beam and/or provide fixing points for attachment to other building materials. In yet another example, an additional stringer may also extend between the stringer at the top surface and the stringer at the bottom surface, so that the stringers together form a single stringer with an I-shaped cross section. That is, there is effectively an I-beam embedded in the core.

[0146] Materials used for the core, skin, and/or stringers may be any combination of those as described previously for the plank. Similarly, the construction of the skin may also be achieved using any of the options discussed previously, such as a single sheet wrapping around the core, C-shaped sections covering top and bottom surfaces, a single sheet with a U-shaped sheet, or nested U-shaped sheets.

[0147] In some embodiments of the beam in which the top surface of the core is exposed, the skin may be formed by a folded U-shaped sheet, covering the bottom surface and the side surfaces. In these cases, the skin may include inwardly turned flanges along upper edges of the side surfaces. The flanges can improve the structural rigidity of the skin and assist in retaining the core inside the skin, by engaging with the top surface. [0148] Similar to the plank, the beam may also include an end closer, the skin may be glued to the core and/or overlapping portions of the skin may be fixed using fasteners.

[0149] The dimensions of the beam may be similar or different to those described for the plank. However as noted above, beams will generally have a cross section with its width being substantially less than its depth, whereas planks will generally have a cross section with its width being substantially greater than its depth. One preferred embodiment of the beam could have a width of 90mm, depth of 300mm, and length of 6000mm.

[0150] In other examples, the width may be varied to some other desirable dimension, such as but not limited to between 50mm and 100mm, greater than 100mm, or approximately 30% of a depth of the beam. In other examples, the depth may be varied to some other desirable dimension, such as but not limited to between 200mm and 400mm, greater than 300mm, or greater than 300% of a width of the beam. In other examples, the length may be varied to some other desirable dimension, such as but not limited to greater than 6000mm, or greater than 10 times a depth of the beam.

[0151] Various applications for the beam are possible. In one example, a frame for a doorway or similar opening in a building may be constructed where at least the lintel is formed using a beam as described above. Many other applications are also possible, including other portions of house or building construction, or carports and other related structures.

[0152] An example of a panel according to the invention that is suitable for use as a building material will now be described. In this example, the panel has a core with a rectangular cross section. This core is covered by an outer skin that substantially covers at least a top surface, a bottom surface, and two side surfaces.

[0153] It will be appreciated that a panel will typically have a substantially wider rectangular cross section compared to a plank, but may otherwise share many of the construction features as described above for the examples of the plank.

[0154] This panel has many of the same advantages as the plank and/or beam described previously, and some optional forms of the panel may also have many of the same features. A number of these other features will now be described, which may be optional or advantageous aspects of some example embodiments.

[0155] In one example, panel has at least one stringer forming part of the core and extending in a longitudinal direction along the panel. This stringer may be formed in a similar manner to those described previously.

[0156] Materials used for the core, skin, and/or stringers may be any combination of those as described previously for the plank or beam. Similarly, the construction of the skin may also be achieved using any of the options discussed previously, such as a single sheet wrapping around the core, C-shaped sections covering top and bottom surfaces, a single sheet with a U-shaped sheet, or nested U-shaped sheets. For the panel, there may also be an additional skin portion to cover ends of the panel.

[0157] Similar to the plank and beam, the panel may also include an end closer, the skin may be glued to the core and/or overlapping portions of the skin may be fixed using fasteners.

[0158] An example of a method of constructing a floor using components described previously will now be described. In one example, the planks are laid so that the side surfaces abut one another. In such an example, the side surfaces that abut one another may be held in place using double sided tape.

[0159] In another example of the method, the planks are laid so that the side surfaces are parallel to one another. A distance between adjacent side surfaces may be any suitable value, such as but not limited to, approximately 400mm, between 350mm and 450mm, greater than 300mm, greater than 200mm, or greater than 50% of a width of a panel.

[0160] When the planks are laid with gaps between, the planks may have flooring sections affixed, with additional flooring sections placed between and spanning the distances between adj acent planks . Alternatively, the planks could have flooring sections affixed in a way that the flooring sections overhang at least one side of the plank so as to extend across the distance between adjacent planks.

[0161] A wide range of uses exist for the above described planks, beams and panels. For example, a floor may be constructed as described above where the planks are supported by at least one beam. In another example, one or more planks, beams, and/or panels may be used to create form work for constructing a concrete slab.

[0162] Various other example embodiments of the invention will now be described with specific reference to the figures.

[0163] Referring to Figure 1, an example embodiment of a plank 100 is shown. The plank has a top surface 101, side surfaces 102, a bottom surface 103, and ends 104. As shown in Figure 2, the plank 100 has an outer skin 105 and a core 106 that includes four stringers 107. In the preferred embodiment, the core 106 is made from EPS foam while the stringers 107 are made from timber.

[0164] Referring now to Figure 3, an alternative embodiment is shown that includes an additional stringer 108 that runs along a central part of the top surface 101. The stringers 107 are useful for providing a secure base into which screws, nails, or other fasteners can be inserted. Accordingly, it may be desirable to configure the core 106 in many other ways depending on a particular application.

[0165] Some stringers may also be formed using different materials if their purpose is related more to improving the strength of the panel rather than for providing a base for fasteners. In this regard, Figure 4 shows a plank 100 where the comer stringers 107 are made from timber while a central stringer 108 is made from steel channel. In yet another example as shown in Figure 5, all of the stringers are formed using steel channels.

[0166] Figure 6 shows yet another example embodiment of a plank 100, which is similar to that shown in Figure 5 in that steel channels are used for the comer stringers 107. However, this example also has one or more layers of ply 109 attached prior to the skin 105 being wrapped around the entire assembly. It will be appreciated, however, that ply blocks or other forms of stringers as described previously could also be used in this example in place of the steel channels.

[0167] Figure 7 shows yet another embodiment of a plank 100, which is a variation on the embodiment from Figure 6. In this example, the foam of the core 106 has been replaced with a series of ribs 118. The space between the ribs 118 may be left open, or may be filled with a foam, insulation, or any other core option as discussed previously. Holes 119 may optionally be provided in the ribs 118 to allow for services.

[0168] Figure 8 shows yet another embodiment of a plank 100. This embodiment includes C- shaped stringers 107 made from ply wood or similar, in addition to the ply 109 forming the upper and lower surfaces inside the skin 105. Once again, the remainder of the core may be left as a void or may be filled with a suitable core material as discussed previously.

[0169] Referring to Figures 9 to 12, various options for forming the skin 105 of the panels 100 are shown. These Figures are shown in an expanded form for illustrative purposes only, as the skin 105 is fixed directly to the core 106 in practice.

[0170] In Figure 9, the skin 105 is formed by a combination of C shaped pieces 110 that wrap around the side surfaces 102 and flat sheets 111 that are fixed to the top surface 101 and the bottom surface 103. This design is also shown in Figures 13 and 14. In Figure 10, a single sheet 112 wraps around much of the core 106 with a C shaped piece 110 capping the remaining side surface.

[0171] In Figure 11, a flat sheet 113 covers the top surface 101 while a U shaped piece 114 wraps around the side surfaces 102 and the bottom surface 103. This design is also shown in Figures 15 and 16. Similarly, Figure 12 shows an embodiment where there are two nested U shaped pieces 114.

[0172] Referring now to Figure 17, an example of an installation is shown where planks 100 are laid so that the side surfaces 102 are parallel to one another. This setup leaves a gap 120 that may be used for running services or simply to reduce the number of planks 100 that are required. The planks have flooring sections 122 affixed in a way that the flooring sections overhang at least one side of the plank 100 so as to extend across the distance between adjacent planks 100.

[0173] Referring to Figure 18, an example is shown where planks 100 are laid so that the side surfaces 105 abut one another. In such an example, the side surfaces that abut one another may be held in place using double sided tape 125. [0174] Referring to Figure 19, an example embodiment of a beam 200 is shown. The beam 200 has atop surface 201, side surfaces 202, a bottom surface 203, and ends 204. As shown in Figure 20, the beam 200 has an outer skin 205 and a core 206 that includes two stringers 207. In the preferred embodiment, the core 206 is made from EPS foam while the stringers 207 are made from timber.

[0175] Figure 21 shows another embodiment where a stringer 208 is constructed in the form of an I-beam.

[0176] Figure 22 shows yet another example embodiment where the core 206 has a stringer 209 constructed in the form of an I-beam from a material such as plywood or similar, with the remainder of the core 206 being hollow. In this particular example, the skin 205 is formed as shown in Figure 23, being substantially wrapped by a C-shaped skin component 212 before then placing a cap 210 over the remaining section and overlapping.

[0177] It will be appreciated that each of the options discussed previously for forming the skin 105 of the plank 100 may also be used in a similar manner for forming the skin 205 of the beam 200.

[0178] Figure 24 shows yet another example embodiment where the core 206 has two timber stringers 207, one abutting the skin 205 at the top surface 201 and one abutting the skin 205 at the bottom surface 203. There are also two additional stringers 215 abutting the skin 205 at each of the side surfaces 202. These additional stringers 215 may be made from plywood or similar. As shown in Figure 25, the core 206 may be substantially hollow, with timber noggins 216 spaced along the length of the beam 206 and at the ends 204, with those at the ends being of larger width to allow for cutting a small amount from the end beam when adjustments in overall length are required.

[0179] Figure 26 shows yet another example embodiment, similar to the embodiment of Figure 24 but with the void filled using a non-combustible material 217. Use of the non-combustible material may remove the need for some or all of the noggins 215, as shown in Figure 27.

[0180] As mentioned above, in some alternative embodiments of the beam, the top surface of the core 206 is not covered by the outer skin 205. Figure 28 shows a specific example of the skin 205 of such an embodiment of the beam (with no core materials shown). In particular, the skin 205 is formed by a U-shaped skin component 218 with an open top.

[0181] Inwardly turned flanges 219 are formed along upper edges of the side surfaces of the skin component 218. These flanges 219 can improve the structural rigidity ofthe beam and can also assist in retaining the core 206 inside the skin 205.

[0182] Figure 29 shows an alternative example of the skin 205 of the beam (with no core materials shown), which effectively provides an outer skin 205 profile similar to the version shown in Figure 28, albeit with a different construction which also provides internal reinforcement to the beam. In this case, the skin 205 is formed by two U-shaped skin components 220, 221. Each skin component has interior surfaces that are bonded together inside the beam, and side surfaces which are relatively higher compared to the interior surfaces and define the open top of the skin 205.

[0183] Inwardly turned flanges 219 are also formed along upper edges of the respective side surfaces ofthe skin components 220, 221, as per the previous example. Internal flanges may also be formed along upper edges of the interior surfaces of the skin components 220, 221.

[0184] In either of the examples of Figures 28 and 29, the outer skin 205 may be used as formwork in combination with a core 206 and grout, whereby the grout can be poured into voids formed between the core and the skin 205 and allowed to cure to effectively form the stringers, as discussed above.

[0185] Further details of specific implementation features of the beam will now be described.

[0186] In some embodiments, the beam will include a metal skin that is folded (for example as shown in Figures 28 and 29) to create a formwork for a lightweight core material, reinforcing steel and high strength grout, to thereby provide a composite beam.

[0187] The grout may be formed using a grout powder, which may be a proprietary pre-made material or a standard material available from suppliers. The grout powder may contain synthetic or metal fibres, or other additives to increase the tensile capacity and structural performance of the cured grout. [0188] The grout powder, when mixed with water, forms a slurry, which can be poured into the beam formwork and over time will cure and set hard. This hardened state of the slurry material will become the grout as discussed above, which will effectively define stringers of the composite beam.

[0189] Unfilled beams are a lightweight, pre-finished formwork system that are easy to carry and install with minimal or no propping. Lengths can easily be modified to suit on-site measurements. Filled beams can be made to order and delivered to site pre-filled, craned into position and fixed into place using pre-installed fixing points.

[0190] This approach to forming a composite beam can have a range of associated advantages, as outlined below.

[0191] The composite beam can be pre-finished, meaning it doesn’t need to be painted, sheeted, blocked and sheeted or covered in any way.

[0192] It provides a combination of metal sheet materials, reinforcing, grout, and lightweight void forming materials, all of which can be located strategically to form a long spanning structural composite beam with desirable strength and weight characteristics.

[0193] To help these materials achieve enhanced composite action, a grit or similar material may be applied on the inside faces of the metal form. This can create a mechanical/frictional bond between the metal skin and the grout, which can then act as one synergistic, cooperative combination, rather than two separate materials.

[0194] The metal skin can be folded to form beam shaped profiles of the desired sizes. For example, 70mm wide and 250mm high, or 90mm wide and 300mm high. The metal sheet can be Zincalume, Colourbond, Stainless Steel, depending upon the required application and finish.

[0195] End caps of the same material can be fitted at each end of the beam, and can support captive nuts and other fitments to facilitate connections from the beam to the supporting structure. [0196] A lightweight core material of polystyrene, cork or compressed plant material, such as straw (Durra Panel or similar), may be assembled to support the reinforcing elements in the preferred configuration.

[0197] In addition to supporting the reinforcing elements, the lightweight core material forms voids between it and the metal skin formwork. For example, the lightweight core material may form voids at the top and bottom of the formwork (chords) and vertically or diagonally (struts and braces) to connect the top void with the bottom void. These voids may contain reinforcing elements and later the grout that will be poured into the formwork when required. This lightweight core material may also restrain the metal skin formwork from bulging with bursting pressures that occur when the grout is poured.

[0198] The reinforcing elements may be steel, fibre glass or carbon fibre elements in the top and bottom voids (chords), connected by similar elements through the vertical and or diagonal voids (struts and braces).

[0199] The lightweight core material and the reinforcing elements may be assembled as one unit prior to placing into the metal form. Adhesive elements may be applied to the faces of the lightweight core material, which is then placed inside the metal skin formwork. Then pressure may be applied until the adhesive has cured.

[0200] Once the adhesive has cured, the end caps with their fitments are attached to the formwork and engaged with the reinforcing. To adjust the length of the beam, prior to pouring the grout, one of these end caps can be removed, and the form work together with the reinforcing elements can be cut to the desired length. The removed end cap and fitments can be refitted, installed and fixed in place, ready for pouring the grout.

[0201] The beams can be filled with grout at any time after assembly. That could be at the place of manufacture or on the work site. The grout is high strength and high slump and can be mixed in a bucket with a drill powered mixer. This grout can be poured or pumped into the top of the formwork, and flows into all the voids and around the reinforcing. [0202] Additional fixings like captive nuts or threaded studs can be installed to the top of the beam, during manufacture or as the grout is being poured. These fixings can be used to connect other structural elements, like joists, top plates or trusses to the beam.

[0203] Beams can be built into a structure or exposed as a finished element. In some examples, Colourbond sheeting may be used to form the metal skin form work. The Colourbond sheeting has a protective membrane, and when peeled off reveals a high-quality durable finish in a variety pre-finished colour or pattern options.

[0204] In some examples, beams formed with stainless steel could contain glass or carbon fibre reinforcing, with stainless steel fitments making them suitable for extreme marine environmental applications.

[0205] An example of a composite beam 300 as discussed above is shown in Figures 30A to 30J. In this example, the outer skin 305 is similar to the example of Figure 28, being formed by a U-shaped sheet metal component with an open top and inwardly turned flanges as previously discussed.

[0206] Elements of the core can be seen in the cross section of Figure 30A. The core includes infills 306 formed from a lightweight material, reinforcements, which in this case include plate reinforcements 308 and angle reinforcements 309, inserts, such as threaded end connectors 310, threaded top connectors 311 and sleeves 313, and grout 307, which fills the internal volume of the skin 305 that is otherwise not filled by the other core elements.

[0207] As can be seen in the Figure 30B, an end cap 312 is used to form a closure with the skin 305 at the end of the beam 300, to thereby retain the grout and to provide a mating surface within which threaded end connectors 310 are provided. The end cap 312 is typically formed from folded sheet metal, similar to the skin 305. With regard to Figure 30C, which shows the reinforcements of the beam 300, the plate reinforcements 308 are formed from stamped metal plates, and opposed pairs of the angle reinforcements 309 are attached to edges of the plate reinforcements. This attachment may be by welding, riveting or any other suitable attachment method. [0208] Turning to Figure 30D, the infills 306 are arranged on either side of the plate reinforcements 308, and as seen Figure 30A, the infills 306 are nested between the plate reinforcements 308 and the skin 305. In this example, the infills 306 have a trapezium-shaped cross section. The inserts, including the threaded connectors 310, 311 and the sleeves 313 are provided to allow the beam 300 to be connected to other structural elements, including other beams 300. These inserts may be attached to the reinforcements, such as by welding, or may be retained relative to the core elements in any other suitable manner. As can be seen in Figure 30E, the end cap 312 is positioned so that the threaded connectors 310 and the sleeves 313 align with holes defined in the end cap 312.

[0209] Figure 30F shows that the skin 305 extends the full length of the beam 300, which in this case is 6000 mm long and 250 mm deep. Figure 30G shows the same beam 300 with the skin 305 and grout 307 hidden, revealing the infills 306 that extend along the beam 300. Figure 30H shows the beam 300 with the infills 306 also hidden, revealing the reinforcing plates 308, which have stamped cutouts to reduce the reinforcement weight.

[0210] One of the end caps 312 is hidden in Figure 30G and a detailed view of this end of the beam 300 at Detail A is shown in Figure 301. This illustrates the positioning of the threaded connectors 310, 311 and the sleeves 313 relative to the reinforcements 308, 309 and the infills 306. The top view of Figure 30J also illustrates how the threaded connectors 310, 311 and the sleeves 313 are positioned relative to the skin 305.

[0211] As mentioned earlier, the threaded connectors 310, 311 and the sleeves 313 can allow the beam 300 to be connected to other structural elements. In this regard, Figures 31 A and 3 IB show two of the beams 300 connected together at their ends, at right angles. The beams 300 may be connected using threaded rods or bolts which are inserted through sleeves 313 of one of the beams 300 and screwed into threaded end connectors in the other one of the beams 300. Figure 31A also shows the grout 307 exposed at the top surface of the beams 300.

[0212] The examples of Figures 32A to 32C and Figures 33A to 33C illustrate some variations to the arrangements of core elements that may be used in alternative embodiments of the beam 300, which will now be described. [0213] The example of Figures 32A to 32C shares many common features with the previous example of Figures 30A to 30J, although the pairs of angle reinforcements of the previous example have been replaced with upper and lower reinforcement bars 314, which are typically welded to edges of the reinforcement plates 308. It is also noted that the infdls 306 have a rectangle-shaped cross section in this case, in contrast to the trapezium-shaped cross section of the previous example. Otherwise, this example provides similar configurations of the skin 305, the end cap 312 and the inserts including the threaded connectors 310, 311 and the sleeves 313.

[0214] In the example of Figures 33A to 33C, upper and lower reinforcement bars 314 are attached to a U-bar 315 at each end of the beam 300, which effectively removes the need for the reinforcement plates 308 as used in the two earlier examples. Reinforcement ligatures 316 are fitted around the upper and lower reinforcement bars 314 at spaced apart intervals along the beam 300 to create a rigid cage-like reinforcement structure within this example of the beam 300. In this example, the infills 306 are provided as plywood boards that are positioned outside of the reinforcement ligatures 316, against the sides of the skin 305.

[0215] It will be appreciated that the example of Figures 33A to 33C may utilise standard reinforcing bars/rods that can be formed into the required shapes using techniques that will be familiar to those skilled in the art of preparing reinforced cast concrete structures.

[0216] However, this example once again provides similar configurations of the skin 305, the end cap 312 and the inserts including the threaded connectors 310, 311 and the sleeves 313.

[0217] In the foregoing description of preferred embodiments, specific terminology has been resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as “front” and “rear”, “inner” and “outer”, “above” and “below” and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.

[0218] Throughout this specification and claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers. As used herein and unless otherwise stated, the term “approximately” means ±20%.

[0219] Persons skilled in the art will appreciate that numerous variations and modifications will become apparent. All such variations and modifications which become apparent to persons skilled in the art, should be considered to fall within the spirit and scope that the invention broadly appearing before described.