EP1365082B1

EP1365082B1 - Panel

Info

Publication number: EP1365082B1
Application number: EP03253224A
Authority: EP
Inventors: Rutherfoed William; Tedesco Dominic
Original assignee: Clydesdale Bank PLC
Current assignee: CLYDESDALE BANK PLC
Priority date: 2002-05-23
Filing date: 2003-05-23
Publication date: 2011-06-15
Anticipated expiration: 2023-05-23
Also published as: ATE513094T1; GB0211861D0; EP1365082A1

Abstract

This invention relates to a vapour-permeable structural panel (10) comprising a cellular panel member (12) and at least one reinforcing layer (18,20) defining a plurality of apertures (26) adhered to at least one surface of the cellular panel member (12). The invention also relates to a wall section (100, 200, 300, 400) comprising a frame (110, 210, 310, 410) forming a support structure and at least one vapour-permeable structural panel (10). <IMAGE>

Description

FIELD OF THE INVENTION

This invention relates to vapour-permeable panels and their use in the building and construction industry. This invention also relates to wall sections comprising vapour-permeable panels.

BACKGROUND OF THE INVENTION

Conventionally, the walls (i.e. shells) of the majority of residential property such as houses and flats, industrial property such as warehouses and factories, retail property such as shop units and shopping centres, and indeed any other type of building structure, have been constructed from bricks and/or building blocks such as breeze blocks. The bricks and/or building blocks are adhered to one another using cement. Constructing buildings in this manner is a time consuming process which significantly contributes to the cost of a building. A skilled tradesman is also required in the construction of a brick wall.
A brick wall also tends to have imperfections such as slight curvatures and distortions which leads to, for example, difficulties when applying an outer finish such as render.
Furthermore, on the completion of a brick wall, the wall goes through a 'drying-out' process whereupon there may be some shrinkage in the wall which may lead to cracking and a loss of structural integrity.
The building of a brick wall may also be affected by bad weather such as frost and heavy rain. Additionally, brick walls may also be susceptible to dampness as bricks and cement have a tendency to retain moisture.
Building brick walls has the further disadvantage that brick walls are relatively heavy and require deep foundations to support the weight of a formed building. If deep foundations are required, this significantly adds to the cost of a building.
GB2314526 relates to a noise attenuation panel. The attenuation panel has a facing sheet comprising apertures but a backing sheet with no perforations and Is therefore vapour impermeable.
It is an object of embodiments of the present invention to obviate or at least mitigate at least one or more of the aforementioned problems.
It is an object of embodiments of the present invention to provide a vapour-permeable panel which may be used in the construction of a building.
It is a further object of embodiments of the present invention to provide a wall section for efficiently and cost effectively constructing the framework of a building.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided vapour-permeable structural panel comprising:

a cellular panel member formed from a metal or alloy; and
reinforcing layers defining a plurality of apertures adhered to a first and second surface of the cellular panel member;
wherein the cellular panel member comprises a plurality of passageways which extend transversely through the cellular panel member and which, in use, allow vapour to permeate through the reinforcing layers from one side of the structural panel to the other; and
the cellular panel member defines a series of perforations which, in use, allow longitudinal vapour transmission.

The reinforcing layer provides additional strength to the cellular panel member while allowing vapour to permeate from one side of the structural panel to the other.
The cellular panel member may comprise a structural network with a plurality of interconnecting cell walls or edges. The interconnecting cell walls or edges may be welded or adhered together with, for example, a resin, glue or adhesive film.
Typically, the interconnecting cell walls have a thickness of between 0.007mm to 1mm.
The cellular panel member comprises a plurality of passageways which extend transversely through the cellular panel member and which, in use, allow vapour to permeate from one side of the structural panel to the other. The passageways may form a regular or an irregular pattern. Typically, there is only one shape of passageway. Alternatively, there may be a mixture of shapes of passageways.
The cellular panel member comprises a plurality of passageways the shape of which may be selected from any of the following: circular; elliptical; triangular; any type of tetragon such as a square, rectangle, parallelogram or rhombus; pentagonal; hexagonal (for example, in the form of a honeycomb); heptagonal; octagonal; nonagonal; decagonal or any other type of polygon.
Conveniently, the passageways in the cellular panel member have a cross-sectional area of between 0.1 to 5cm². Typically, the passageways have a cross-sectional area of about 1cm².
Preferably, the cellular panel member is formed from sheet aluminium alloy. The cellular panel member defines a series of perforations which, in use, allow longitudinal vapour transmission. The perforations may be substantially circular with a cross-sectional area of about 0.007mm² to 1mm². The perforations may be in a regular or an irregular pattern.
The cellular panel member may also be filled with an insulating material such as a foam. The foam fills the passageways in the cellular panel member. The foam may be a phenolic foam. Depending on the type of foam used, the foam may act as an insulating layer for thermal or sound transfer.
Preferably, the at least one reinforcing layer is formed from fibreglass, a fibreglass composite material, a fibreglass mat or chopped fibreglass strands.
The at least one reinforcing layer may have a thickness of between 0.01 to 5mm. Typically, the at least one reinforcing layer has a thickness of about 0.5mm.
Preferably, the at least one reinforcing layer comprises a woven structure of interlacing fibres. The interlacing fibres of the woven structure may be substantially perpendicularly oriented forming a mesh-like structure.
Typically, the apertures in the at least one reinforcing layer are formed in a substantially regular pattern, and may be in rows and columns between interlacing fibres of a woven structure.
Alternatively, the at least one reinforcing layer comprises a polymeric material.
Each aperture in the at least one reinforcing layer may have a cross-sectional area of about 0.01 to 0.5cm² and may be present in a density of 1 to 10 apertures per cm².
The vapour-permeahle structural panel may have a thickness of between 5mm and 50mm. Typically, the vapour-permeable structural panel has a thickness of about 10mm, 15mm or 20mm.
Typically, the vapour-permeable structural panel has a weight of about 1 to 3kg/m².
According to a second aspect of the present invention there is provided a method of forming a vapour-permeable structural panel comprising:

providing a cellular panel member formed from a metal or alloy; and
adhering reinforcing layers onto a first and second surface of the cellular panel member wherein the reinforcing layers define a plurality of apertures;
wherein the cellular panel member comprises a plurality of passageways which extend transversely through the cellular panel member and which, in use, allow vapour to permeate through the reinforcing layers from one side of the structural panel to the other; and
the cellular panel member defines a series of perforations which, in use, allow longitudinal vapour transmissions.

Conveniently, the cellular panel member is formed from sheet metal, polymeric material, alloy or wood pulp. Most preferably, the cellular panel member comprises sheet material.
Adhesive material such as resin may be applied in, for example, substantially parallel lines into the sheet material. The sheet material may then be cut and folded, or otherwise arranged, into layered sections so that the parallel lines of adhesive are staggered from one layer to another. The folded cut sections may then be heated under pressure. The folded cut sections may then be pulled apart to form the cellular panel member. The stretching may be electronically or manually controlled.
A form may be incorporated into the cellular panel member by pressing a foam material into the cellular panel member. The foam may be a phenolic foam.
Preferably, the at least one reinforcing layer is formed from woven fibreglass, a fibreglass composite, a fibreglass mat or chopped fibreglass strands. The fibres of the fibreglass , fibreglass composite, fibreglass mat or chopped fibreglass strands may be bound to other fibres of the fibreglass, fibreglass composite, fibreglass mat or chopped fibreglass and to the cellular panel member, with a resin or other settable material. The resin may be a polyester resin, epoxy resin, phenolic resin, polyreutamic resin or combinations thereof.
Preferably, the fibres of the fibreglass, fibreglass composite, fibreglass mat or chopped fibreglass strands are woven forming a layer with interlacing fibres separated by a plurality of apertures. The interlacing fibres may be substantially perpendicularly oriented.
Typically, the at least one reinforcing layer is applied to a surface of the cellular panel member with a heated roller. The heated rollers sets the resin in the reinforcing layer, binding the reinforcing layer to the cellular panel member. If required further heating steps to fully set the resin may be used.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective part cut-away view of a vapour-permeable structural panel according to a first embodiment of the present invention;
Figure 2 is a sectional part top view of the vapour-permeable structural panel shown in Figure 1;
Figure 3 is a perspective 'see-through' view of a cellular panel member of the vapour-permeable structural panel shown in Figure 1;
Figure 4 is a sectional side view of the vapour-permeable structural panel shown in Figure 1 illustrating vapour and air flow;
Figure 5 is a perspective part cut-away view of a wall section according to a second embodiment of the present invention;
Figure 6 is a sectional side view of a wall section according to a third embodiment of the present invention.
Figure 7 is a sectional side view of a wall section according to a fourth embodiment of the present invention;
Figure 8 is a sectional view of an insulating section used in the embodiment shown in Figure 7;
Figure 9 is a front view of the insulating section shown in Figure 8;
Figure 10 is a sectional side view of a wall section according to a fifth embodiment of the present invention;
Figure 11 is a perspective view of a drainage unit used in the embodiment shown in Figure 10; and
Figure 12 is a side view of the drainage unit shown in Figure 11.

DETAILED DESCRIPTION

Shown in Figure 1, there is a vapour-permeable structural panel generally designated 10 according to a first embodiment of the present invention. The vapour-permeable structural panel 10 comprises a cellular panel member 12 with front and back surfaces 14, 16. Reinforcing fibreglass layers 18, 20 are adhered to the front and back surfaces 14, 16 of the cellular panel member 12, respectively.
Figure 2 illustrates the form of the cellular panel member 12, that is a hexagonal honeycomb with a plurality of interconnecting walls 22 and edges 24 forming a plurality of passageways 26. The passageways 26 form a structural network and have a cross-sectional area of about 1cm².
Figure 3 shows that the passageways 26 in the cellular panel member 12 comprise a plurality of perforations 28 extending linearly along the centre of each wall 22. The perforations have a cross-sectional area of about 0.05mm² and enable vapour to permeate therethrough.
The reinforcing fibreglass layers 18, 20 on the front and back surfaces 14, 16 of the cellular panel member 12 provide additional strength to the panel 10 and are in the form of a woven structure with interlacing fibres substantially perpendicularly oriented. Between the interlacing fibres there is a plurality of apertures 30.
The cellular panel member 12 is formed by applying adhesive in parallel lines onto sheet aluminium alloy. The aluminium alloy is then perforated with needles, and cut and folded into layered sections so that the parallel lines of adhesive form a staggered pattern from one layer to another. The folded sections are then heated under pressure to set the adhesive, and then pulled apart to form the cellular panel member 12. Reinforcing fibreglass layers 18, 20 in a "wet form" are then applied using a heated set of rollers onto the front and back surfaces 14, 16 of the cellular panel member 12.
Figure 4 illustrates the function of the vapour-permeable structural panel 10 when used as part of a wall section for forming the framework of a building. Due to the apertures 30 in the reinforcing fibreglass layers 18, 20 and the passageways 26 in the cellular panel member 12, vapour may permeate from one side of the panel 10 to the other. Figure 4 also shows that if any vapour collects in the passageways 26 of the cellular panel member 12, the perforations 28 allow vapour transmission so that, in use, vapour permeates through the vapour-permeable structural panel 10. Figure 4 also shows that air flows up and down within the panel 10 which also helps to disperse any vapour.
A vapour-permeable structural panel 10 with a thickness of about 15mm is lightweight with an average weight of about 2kg/m². Panels 10 of up to about 1.2m x 3.1m may be manufactured.
The vapour-permeable structural panel 10 may be used in the construction of walls in buildings and may be fixed directly onto steel, timber or polymeric frames. The vapour-permeable structural panel 10 is highly breathable and prevents or minimises the formation of dampness in a building.
Figure 5 is a representation of a wall section, generally designated 100 according to an embodiment of the present invention. The wall section 100 comprises the following principal parts: a frame 110 forming a support structure; insulating sections 112 and plasterboard layers 114, 116 attached to a first and second face of the frame 110; and a vapour-permeable structural panel 10, as previously described, attached to the insulating sections 112.
The frame 110 includes a channel shaped top section 118, a series of channel shaped vertical support sections 120 and a channel shaped bottom section 122. As shown in Figure 5, the top and bottom channel shaped sections 118, 122 extend along the length of the wall section 100 and are similarly shaped. The vertical support sections 120 are shorter channel shaped sections. The top, vertical and bottom channel shaped sections 118, 120, 122 are about 140mm x 41mm x 1.2mm in dimension.
Figure 5 shows that the vertical support sections 120 are received inside the channel shaped top and bottom sections 118, 122. The vertical support sections 120 are initially slid into the channel shaped top and bottom sections 118, 122. When the vertical support sections 120 are in position they are secured to the channel shaped top and bottom sections 118, 122 using rivets.
The frame 110 forms at least one chamber which is open at the front and back. By using long lengths of top and bottom channel shaped sections 118, 122 and a plurality of vertical support sections 120 an extended frame 110 is formed which is used to form the wall section 100. The spacing of the vertical support sections is dependent on the loading requirements in a particular building.
Insulation material 124 such as blocks of 100mm thick glass wool are inserted into the open chamber in the frame 110.
The insulating sections 112 are attached to a first face of the frame 110 on the top, vertical and bottom sections 118, 120, 122 using screws and adhesive pads. The insulating sections 112 are about 15mm thick and are formed from extruded polystyrene. The insulating sections 112 attached to the top and bottom sections 118, 122 of the frame 110 feature vertical grooves (not shown). The vertical grooves enable any vapour to escape along the grooves and to exit through a drainage hole (not shown). The insulating sections 112 provide a thermal barrier between the metallic frame 110 and the vapour-permeable structural panel 10 minimising heat loss from a building.
The insulating sections 112 are also attached with screws and a top hat fixing with thermal cap 130 to the vapour-permeable structural panel 10. The vapour-permeable structural panel 10, as described before, has a cellular panel member 12 with reinforcing layers 18, 20 adhered thereto. The panel 10 is about 15mm thick. Any vapour formed in the cellular panel member 12 may permeate through the perforations 28 in the interconnecting walls 22 and exit through a drainage hole (not shown) or permeate through the passageways 30 in the reinforcing layers 18, 20.
On a second side of the frame 110 two layers of, for example, 12.5mm plasterboard 114, 116 are attached using self drilling screws or bonding. Plasterboard layer 114 has a vapour barrier coating 115 of polythene which prevents any moisture from entering a building. The plasterboard layers 114, 116 form the inside surface of a building. Between the plasterboard layers 114 , 116 and the insulation material 124 there is an air gap 132 which prevents or minimises any build up of condensation and may be used as an access point for any type of servicing and/or maintenance. Electric wiring may be run through the air gap 132.
Furthermore, as shown in Figure 5 a glass matting 134 embedded in resin is adhered to the vapour-permeable structural panel 10.
On top of the glass matting 134 embedded in resin there is a 3mm coating of acrylic render 138 which provides a weather resistant external surface.
Alternatively, on the outer surface of the vapour-permeable panel 10 a variety of different surfaces may be applied which may be selected from one or more of the following: traditional render; wet dash; acrylics; marble; terracotta; dry dash; tyrolean finishes; high build finishes; ceramics; timber and aluminium finished metal glass mirrors; stone; granite; and silicone based coatings.
The wall section 100 is wind and waterproof and will have a minimum life of at least 60 years.
Figure 6 is a representation of a wall section, generally designated 200 according to a further embodiment of the present invention. The wall section 200 is very similar to the wall section 100 shown in Figure 5. The wall section 200 comprises the following principal parts: a frame 210 forming a support structure; insulating sections 212 and plasterboard layers 214, 216 attached to first and second faces of the frame 210, respectively; and a vapour-permeable structural panel 10, as previously described, attached to the insulating sections 212.
In Figure 6, the wall section 200 is also shown to include insulation material 224, an air gap 232 and an acrylic and adhesive render system coating 238.
The main difference in wall section 200 is that the insulation material 224 is raised above the base of the wall section 200 with an inverted channel shaped metallic section 250. This helps to prevent or minimise any dampness forming in the wall section 200 by raising the insulation material 224 above any lying water.
The weight of the different parts of the wall section 200 are as follows: the frame 210 is about 11kg/m²; the insulation material 224 is about 11kg/m²; the insulating sections are about 0.11kg/m²; the vapour-permeable structural panel 10 is about 2kg/m²; and the acrylic and adhesive render system coating 238 is about 5kg/m². The total weight of the wall section 200 is about 29.11kg/m².
Figure 7 is a representation of a top part of a wall section, generally designated 300 according to a yet further embodiment of the present invention. The wall section 300 comprises the following principle parts: a frame 310 forming a support structure; insulating sections 312 and plasterboard layers 314, 316 attached to first and second faces of the frame 310, respectively; and a vapour-permeable structural panel 10, as previously described, attached to the insulating sections 312.
The wall section 300 shown in Figure 7 is very similar to that shown in Figure 6 and includes insulating material 324, an air gap 332 and an acrylic and adhesive render system coating 338. The wall section 300 also has a polythene vapour barrier 317 situated between the frame 310 and the plasterboard layer 314,316. Furthermore, and as shown in Figure 7, the insulating sections 312 along with the vapour-permeable structural panel 10 are attached to the frame 310 with a screw 350 with a top hat fixing 352.
The main difference in wall section 300 is that the insulating sections 312 are substantially 'T'-shaped and have a recess on the top of the 'T' which engages the frame 310. This enables the insulating sections 312 to snugly fit onto the horizontal and vertical sections of the frame 310.
Figure 8 is a sectional side view of an insulating section 312 and shows the respective dimensions in millimetres. Figure 8 also shows that the recess is tapered which enables the insulating section to grip onto the edge of the frame 310.
Figure 9 is a front view of the insulating section 312 which shows that there are vertical grooves 313 which are used to form drainage channels to enable any vapour or moisture to escape. The grooves are about 5mm X 5mm and are spaced apart by about 20 mm. As shown in Figure 7, drainage channels 315 are thus formed between the insulating section 312 and the vapour-permeable structural panel 10. The drainage channels 315 enable any moisture to drain away and any vapour to disperse.
The shape of the insulating sections 312 have the advantageous effect of surrounding the surface area of the metal frame 110. As the insulating sections 312 are made from extruded polystyrene (i.e. an insulator) this has the advantageous effect of providing good insulation and thereby preventing loss of heat. Such an arrangement is sometimes called a 'warm frame'.
Figure 10 represents a further wall section, generally designated 400 which is a sectional view of the bottom part of a wall section. The wall section 400 comprises the following principle parts: a frame 410 forming a support structure; insulating sections 412 and plasterboard layers 414, 416 attached to first and second faces of the frame 410, respectively; a polythene vapour barrier 417; a vapour-permeable structural panel 10, as previously described, attached to the insulating section 412; insulating material 424; an air gap 432; and an acrylic and adhesive render system coating 438.
The insulating sections 412 are secured to the frame 410 with a screw 450 with a top hat fixing 452.
As shown in Figure 10, wall section 400 is attached to a window unit 460 which has double glazed panels 462. Foam is injected into the gap 464 between the window unit 460 and the wall section 400. A mastic seal 466 and neoprene sealant tape 468 are used to seal the joint between the vapour-permeable structural panel 10 and the window unit 460. This provides good insulation for a building.
Furthermore, as shown in Figure 10 there is an 'L'-shaped cover bead 470 which has a channel 472 running along the length of the bottom section of the bead 470. The channel 472 has drainage holes 474 arranged at about 100 mm intervals to allow moisture to drain away.
Figure 11 is a perspective view of the 'L'-shaped cover bead 470 which clearly shows the channel 472 and the drainage holes 474.
Figure 12 shows the dimensions of the 'L'-shaped cover bead 470.
It will be clear to those of skill in the art, that the above described embodiments of the present invention are merely exemplary and that various modifications and improvements thereto may be made without departing from the scope of the present invention. For example, the cellular panel member 12 of the vapour-permeable structural panel 10 in the wall sections 100, 200, 300, 400 may have any of the following shapes of passageways 26: circular; elliptical; triangular; any type of tetragon such as a square, rectangle, parallelogram or rhombus; pentagonal; hexagonal (e.g. in the form of a honeycomb); heptagonal; octagonal; nonagonal; decagonal or any other type of polygon.
Any type of attachment or adhesion means may also be used to connect the different parts of the wall sections 100, 200, 300, 400.
The wall sections 100, 200, 300, 400 are quick and easy to construct with the result that the frame of a standard house may be built in a single day. As no cement is used the formed frame also does not need to go through a 'drying-out' process. The building process is also relatively unaffected by bad weather. A flat outer surface is also produced which makes it relatively easy to apply outer finishes.

Performance Test Results of Vapour-Permeable Structural Panel

A vapour-permeable structural panel 10 with a 15mm panel thickness of 9mm² honeycomb cells formed of aluminium alloy, and fibreglass reinforcing layers 18, 20 of 0.5mm underwent a series of performance tests as detailed below:

Fire Propagation Test: panel found to be fire resistant and has a Class 1 rating;
Surface Flame Spread Test: panel found to resist spread of flames and has a rating of 1.0 (British Standard 476);
Tensile Strength in Flatwise Panel: tests showed that the panel had an average maximum load of 5287N and an average tensile strength of 0.77N/mm²;
Flexural Strength (Castas Internal Procedure): the panel was shown to have an average flexural strength of 24.8MPa and an average modulus of elasticity of 3000MPa;
Axial Withdrawal of Fixing Insert (Castas Internal Procedure): the panel was shown to have an average load of 13.49kN;
Artificial Weathering Xenon Light Apparatus: tests showed that the panel was resistant to blistering, cracking, flaking and chalking;
Freeze/Thaw Resistance: panel showed no sign of cracking or flaking, the initial weight of the panel was also unchanged; and
Determination of Thermal Conductance: the thermal conductance of the panel was found to be 33W/m²-K and the thermal resistance was found to be 0.030m²K/W.

Claims

A vapour-permeable structural panel (10) comprising:
a cellular panel member (12) formed from a metal or alloy; and

reinforcing layers (18,20) defining a plurality of apertures (30) adhered to a first and second surface (14,16) of the cellular panel member (12);

wherein the cellular panel member (12) comprises a plurality of passageways (24) which extend transversely through the cellular panel member (12) and which, in use, allow vapour to permeate through the reinforcing layers (18,20) from one side of the structural panel (10) to the other; and

the cellular panel member (12) defines a series of perforations (28) which, in use, allow longitudinal vapour transmission.
A vapour-permeable structural panel according to claim 1, wherein the cellular panel member (12) comprises a structural network with a plurality of interconnecting cell walls (22) or edges (24) wherein the interconnecting cell walls or edges are welded or adhered together with resin, glue or adhesive film.
A vapour-permeable structural panel according to claim 2, wherein the interconnecting cell walls (22) have a thickness of between about 0.007mm to 1 mm.
A vapour-permeable structural panel according to claim 1, wherein the passageways (26) in the cellular panel member (12) have a cross-sectional area of between 0.1 to 5cm².
A vapour-permeable structural panel according to any preceding claim, wherein the cellular panel member (12) is filled with an insulating material such as foam.
A vapour-permeable structural panel according to any preceding claim, wherein the reinforcing layers (18,20) are formed from fibreglass, a fibreglass composite material, a fibreglass mat or chopped fibreglass strands.
A vapour-permeable structural panel according to any preceding claim, wherein the reinforcing layers (18,20) have a thickness of between about 0.01 to 5mm.
A vapour-permeable structural panel according to any preceding claim, wherein the reinforcing layers (18,20) comprise a woven structure of interlacing fibres wherein interlacing fibres of the woven structure are substantially perpendicularly oriented forming a mesh-like structure.
A vapour-permeable structural panel according to any preceding claim, wherein apertures (30) in the reinforcing layers (18,20) have a cross-sectional area of about 0.01 to 0.5cm² and are present in a density of 1 to 10 apertures per cm².
A vapour-permeable structural panel according to any preceding claim, wherein the vapour-permeable structural panel (10) has a thickness of between about 5mm and 50mm.
A method of forming a vapour-permeable structural panel (10) comprising:
providing a cellular panel member (12) formed from a metal or alloy; and

adhering reinforcing layers (18,20) onto a first and second surface (14,16) of the cellular panel member wherein the reinforcing layers (18,20) define a plurality of apertures (30);

wherein the cellular panel member (12) comprises a plurality of passageways (24) which extend transversely through the cellular panel member (12) and which, in use, allow vapour to permeate through the reinforcing layers (18,20) from one side of the structural panel (10) to the other; and

the cellular panel member (12) defines a series of perforations (28) which, in use, allow longitudinal vapour transmission.
A method according to claim 11, wherein adhesive material such as resin is applied in, for example, substantially parallel lines onto a sheet material; the sheet material is then cut and folded, or otherwise arranged, into layered sections so that the parallel lines of adhesive are staggered from one layer to another; the folded cut sections are then heated under pressure; the folded cut sections are then pulled apart to form the cellular panel member (12).
A method according to any of claims 11 or 12, wherein the reinforcing layers (18,20) are applied to a surface of the cellular panel member (12) with a heated roller, wherein the heated rollers set the resin in the reinforcing layer, binding the reinforcing layer to the cellular panel member.