WO1998005835A1

WO1998005835A1 - A flat structure, a method for manufacturing flat structures, an interconnecting element for flat composite structures, as well as a method for erecting structures

Info

Publication number: WO1998005835A1
Application number: PCT/FI1997/000456
Authority: WO
Inventors: Edgar Gudmundsson
Original assignee: Geca Ehf; Eela, Harri
Priority date: 1996-08-07
Filing date: 1997-07-23
Publication date: 1998-02-12
Also published as: JP2000515446A; FI109222B; AU3446497A; CN1232522A; FI963109A; EP0917609A1; FI963109A0

Abstract

The invention relates to a flat composite construction, where a fibre board is placed at a distance from another fibre board and where fastening elements are arranged between the fibre boards. The invention relates also to a method for manufacturing such a composite construction and to a fastening element and to a method for erecting a building construction.

Description

A flat structure, a method for manufacturing flat structures, an interconnecting element for flat composite structures, as well as a method for erecting structures

The present invention relates to a method for manufacturing board-like essentially flat composite structures of a matrix material by subjecting said material to a consolidation process . The present invention also relates to such a structure comprising at least two opposite boards, each two of such boards being interconnected by an interconnecting element, respectively, opposite outer portions of this (these) intermediate element (s) being attached to the material of corresponding opposite boards. The invention further relates to an interconnecting element adapted to be arranged in an essentially board-like composite structure, between opposite boards and capable of lying essentially flat in a seam region between opposite inner board surfaces during the manufacturing of said structure. The invention also relates to a method for erecting essentially flat structures such as walls, floors, ceilings and the like, said structures comprising at least two opposite boards or the like elements, said boards being interconnected by at least one interconnecting element, opposite attachment portions of said interconnecting element being attached to the material of said boards, respectively.

In the house-building industry relatively light-weight structures like walls, ceilings, floors and the like often comprise opposite pairs of a board material interconnected by intermediate spaced posts, girders, beams or the like studs (hereafter called studs) . Said board material may comprise wood boards, plywood, wood-chip boards, boards comprising an inorganic bonding agent, etc. Traditionally such studs were made of wood, but in modern building they are sometimes replaced by studs made of sheet metal . According to prior art said studs are arranged at the intended location of a wall, ceiling, floor and the like, whereafter opposite layers of said board material are fixed to said studs using nails, screws, glue or the like. Depending on the intended use of said structure the intermediate space between opposite board layers may be filled with an insulation material, and often said space is also used for concealing piping, electricity wiring or the like.

The assembling of such flat structures is a major task in building industry. Traditional assembling methods constitute a very laborious phase of the construction work, which must be performed prior to any subsequent installation and finishing work. Structures raised in the traditional manner also represent relatively fixed portions of a building, and thus such structures are not fitted for use of a temporary nature. For temporary use there are quite a lot of special arrangements which, however, usually are less fitted for use of a more permanent nature .

Traditionally a board material which is intended for use in such stud-and-board structures has two essentially smooth surfaces, one of which, however, is turned towards the interior space of said structure, and thus said surface may actually be of a less finished nature. In order to facilitate the attaching of said board material to sa d studs the board material must, however, m all cases have an exact sectional dimension. In the production of sheet boards made of a compressed matrix material like wood chips or the like this demand for exact dimensions constitutes a major problem, especially n developing countries, where it can be difficult to meet the very stringent tolerances typical for modern board industry.

In the present invention this problem is considered from a quite new point of view. In a finished wall or the like structure actually only the outermost surfaces of the sheet boards used must necessarily have a smooth even surface, to satisfy the future use of the finished structure. An exact dimension between opposite inner sides is necessitated only by the fact that said boards are attached to studs of a pre-defined dimension. If the dimensions of said studs could be made to vary slightly in accordance with the dimensions of said opposite boards one could achieve a lower demand for exact dimensions . A problem, however, arises since such studs usually must be arranged at locations where two adjacent boards are interconnected. The other problem is the practical arrangement of studs having dimensions adapted for the actual dimensions of said boards, while still making the outer surfaces even to comply with the intended use.

The first of said problems may be solved by arranging, at adjacent edges of adjacent boards, a groove-and-tongue formation, which is known per se. Regarding the dimensional problem the present invention gives a quite new concept, the characteristics of which are evident from the appended independent claims and especially the characterizing portions thereof. The main inventive concept comprises substituting the studs of the prior art by arranging intermediate essentially flat interconnecting elements between opposite boards during the manufacture or assembly of the composite board structure. The flat interconnecting elements are preferably arranged between at least two opposite boards already during the step of manufacturing the boards. The boards initially lie closely adjacent to each other with the interconnecting element flat between them, but in use the boards are detached from each other and pulled apart to the extent allowed by the interconnecting element thereby forming the finished structure such as a wall, ceiling, floor or the like. In such a composite structure variations in the thickness of the board and a resulting uneven inner surface is of lesser importance.

In practice the invention can be accomplished using interconnecting "stud" elements made of a relatively thin de- formable material, the ends of which extend into the matrix material of said boards and are firmly fixed therein. The ends of the interconnecting elements are preferably attached to the matrix material in an embedded manner, by which term is understood that at least attachment protions of said elements are embedded into the matrix material during the production of the board while the matrix material is still soft, i.e. prior to the consolidation thereof. A method for fixing devices in consolidating boards is decribed in the same applicant's co- pending Finnish patent application FI- 962943 by the same inventor. Said application discloses a method for attaching fasteners to compressed structures, wherein separate means for attaching such boards to external structures or for attaching external structures to said boards comprises tongue-like means which are embedded into the matrix material already during the production of said board. The disclosure of said FI patent application is considered enclosed herein by reference. It w ll be understood by those skilled in the art that the embedded attachment thus provided will be decisively more firm than the attachment provided by pushing, nailing, screwing, glueing or the like prior art attaching methods. However, the present invention should not be considered limited only to embedded attachment structures, and it is evident that the invention provides benefits also with the prior art attaching methods .

More exactly, the present inventive manufacturing method comprises the steps of a) distributing a first layer of said matrix material over at least one first forming area, for generating a first board- like structure body, b) providing at least one separate interconnecting element of a deformable material, said element comprising an intermediate web portion and, connected thereto, at opposite outer portions thereof, attachment means including attachment portions which at least at one of said outer portions are diverted from said web portion, c) arranging on a surface of said distributed matrix material at least one layer of release material. In a further step d) said separate interconnecting element is arranged essentially flat at the surface of said first layer of matrix material so that said intermediate web portion is essentially parallel to said surface and said diverted attachment portion (s) at said at least one outer portion extend, in an embedded manner, into said first matrix material layer, the opposite attachment - portion (s) being adapted to extend into a second layer of matrix material constituting a second structure body of said composite structure, whereafter in step e) said matrix material and said embedded attachment portion are subjected to said consolidation process. Here is to observe that in this context the term embedded manner is intended to define that said embedment takes place prior to a consolidation of said matrix material .

In an essentially flat structure according to a preferred embodiment of the invention at least one second one of opposite boards is cast directly against at least one layer of release material arranged at a surface of a first one of said opposite boards, at least a web portion of said intermediate element (s) extending, during the manufacture of said structure, essentially in the direction of a seam region provided by said release material between said opposite boards. Opposite outer portions of said intermediate element comprise attachment means attached, respectively, to adjacent opposite inner surfaces of said opposite boards at said seam region, said opposite boards being adapted to mutual detachment by increasing the spacing therebetween, said detachment being limited by the extent of said intermediate web portion.

In an interconnecting element according to the invention, which element in the final structure is used as a post, girder, stud or the like means which gives the structure dimensional and structural rigidity, said interconnecting element, which is intended to be arranged essentially flat at at least one of said opposite inner surfaces of said structures, comprises an essentially flat intermediate web portion and, at two outer portions thereof, attachment means comprising attachment portions adapted to divert, at said outer portions respectively, in opposite and essentially transversal directions with respect to said intermediate web portion. Said interconnecting element is manufactured of deformable material and is adapted to bend, in the vicinity of said attachment means and after consolidation of said matrix material into a direction which is essentially transverse to said opposite inner surfaces of said boards.

In the method for erecting structures according to the invention interconnecting elements are provided to extend flat in the direction of a seam region between adjacent board elements. Adjacent opposite boards are forced to mutually depart at said seam region, thereby forcing said interconnecting element or intermediate portions thereof to bend and to extend essentially transversely to said seam region.

The invention will now be described in more detail with reference to the appended drawings, which are, however, to be considered as examples only and which in no way are intended to limit the invention. In said drawings

Figure 1 is a side section disclosing a structure according to one embodiment of the invention,

Figure 2 shows a section of a flat structure which is assembled of structures according to Figure 1, opposite boards of which being forced apart in a seam region,

Figure 3 in section and in more detail shows a compression arrangement according to one embodiment the invention,

Figure 4 shows a portion of an interconnecting element according to one embodiment of the invention, Figure 5 shows a portion of an interconnecting element according to another embodiment of the invention,

Figure 6 in section shows a portion of a compression arrangement for manufacturing a structure according to another embodiment of the invention,

Figure 7 shows the assembling of a structure to yet another embodiment of the invention, and

Figure 8 in section and more in detail shows an example of a portion of a wall and a floor structure in a building, both manufactured using embodiments of the invention.

Referring to Figure 1 the general structure according to the invention comprises at least two opposite board-like essentially flat structures 1, la made of a material having the property of being capable of facilitating the embedment of essentially tongue- and/or finger-like attachment portions 2, 2a arranged to extend, in opposite directions, from a flat intermediate web portion 3 of an interconnecting element generally referred to as 4. The board material may comprise any suitable matrix material into which said attachment portions 2, 2a can be attached in a firm manner. Said intermediate web portion 3 extends essentially in a seam region 5 arranged between said opposite board- like structures 1, la. Said seam region 5 is adapted to facilitate the separation of said opposite boards 1, la from each other. Said seam is preferably obtained by providing at least one layer of release material in said seam region 5, said release material essentially preventing a mutual attachment of the inner portions of said opposite boards 1, la.

According to a preferred embodiment of the invention said matrix material comprises a fibre material like wood chips or the like, and a consolidating component, said matrix material being compressed between press element, in a process known per se , to form a chip board, wherein said attachment portions 2 , 2a will be embedded. In another embodiment said matrix material comprises a settable material which consolidates, even without any essential compression and which is cast between forming elements. In the forming process said attachment portions 2, 2a- will be embedded in the matrix material. As such said materials, as well as said setting components, may comprise gypsum, concrete or the like hardening materials, as well as materials based on settable resins or the like organic glues or other semi-liquid materials. For release material one or several layers any known suitable material can be used, including plastics, preferably well oiled paper or the like sheet-like material, or any suitable fluid based e.g. on Teflon (R) , silicon or the like material preventing a mutual attachment between said matrix material in said seam region 5.

According to the inventive method for erecting structures said opposite board-like structures 1, la are forced to depart, m said seam region 5, using wedge means, clamping means, suction or the like known mechanical or other impac . In Figure 2 this procedure is disclosed by an arrow "A" showing the relative movement of one board 1 with respect to an opposite one la. During the forcing operation an intermediate space 6 is formed in said seam region 5, which space 6 can be used for insulation purposes and/or for arranging piping, electricity and the like. During said operation each of said interconnecting elements 4 will bend, normally at least at a root portion 7 in the vicinity of the inner surface 8 of said board 1, la. Said forcing operation will continue until the distance between the outer surfaces 9 of said boards 1, la corresponds to the desired dimensions of the structure. The intermediate web portion 3 will usually extend, in a manner corresponding to the web in a traditional sheet metal stud, essentially ortho^¬ gonally with respect to said opposite boards 1, la. In certain cases (not shown) said intermediate web may extend in an in- clined or folded manner, which facilitates the adaptation e.g. to an existing wall having a sectional dimension which differs from the maximum thickness of the inventive structure.

In the embodiment shown in Figure 2 a double -structured wall, ceiling or the like structure having essentially smooth outer surfaces 9 has been achieved. Since the inner surfaces 8 of opposite boards 1, la in said structure face said intermediate space 6, which normally cannot be seen from the outside, said inner surfaces may be of a generally rough finish provided by casting and/or compressing said opposite boards 1, la against each other, only with a thin release material separating said boards and preventing an intermixing of the matrix materials of said boards 1, la The materials of the boards 1, la may even be of different materials, if desired

In practice successive ones of such double-structured wall portions will be fitted to form a continuous structure, a portion of which is disclosed in Figure 2 For this purpose said opposite boards 1, la preferably have especially trimmed edges, suitably the interconnecting portions of a groove-and- tongue joint or the like, which m Figure 2 is generally referred to as 10. In this case it is suggested that several boards are manufactured in a parallel manner, whereafter the individual elements are cut out from a larger board prior to trimming the edges. In an other embodiment said edge formation 10 is made directly during the forming process of said boards 1, la, or as a separate trimming step in a later process. In the embodiments shown in Figures 1 and 2 said joints 10 are located in a displaced manner, which gives a good sound and fire insulation.

Figure 3 shows in more detail how interconnecting means 4 are attached by attachment portions 2 to a matrix material 11 distributed on a base plate 12, which in certain favorable embodiments (see also Figure 6) may be a prefabricated board already having other interconnecting elements 4 attached there- to. At least one layer of release material 13, 13a is provided upon the surface 14 of said matrix material 11. Said release material may comprise, as indicated above, any material having the capability of separating opposite layers of matrix material 11, 11a and constituting said seam region between said opposite boards 1, la. According to one preferred embodiment of the invention said interconnecting elements 4 are prearranged between opposite sheets 13, 13a of a sheet-like release material such as oiled paper, suitable plastic films or the like, to form a band-like means which as such is arranged upon the first layer of matrix material. In this case said attachment portions of said interconnecting elements suitably extend through said release material sheets 13, 13a.

A second layer of matrix material 11a will now be provided upon said layer (s) of release material 13, 13a. The attachment portions 2, 2a of said interconnecting element 4 will now extend into a respective one of adjacent layers of matrix material 11, 11a, an intermediate web portion 3 of said interconnecting means 4 extending along a seam region 5 between said material layers 11, 11a.

In the embodiment shown in Figure 3 an upper press plate 12a is now arranged upon said second layer of matrix material 11a. In practice said upper press plate 12a may constitute the lower press plate 12 for a second pair of two matrix material layers and so on, in which case many structures can be stacked and be manufactured in one process. As indicated above said press plates 12, 12a, or at least intermediate press plates m a stack of several structures can, in certain cases, be replaced with prefabricated boards 1 having interconnecting elements 4 embedded in at least one surface thereof.

In accordance with one preferred embodiment of the invention said matrix material 11, 11a comprises a fibre material and a bonding component, said matrix material being compressed, during the manufacture of said boards, to about 1/2 to 1/10 of the dimension of the original matrix material . This procedure is more closely described in said co-pending patent application FI-962943. During such a compression step the attachment portions 2 will be embedded in the matrix material which will provide an especially firm fixation of the interconnecting element 4 to the consolidated board 1. In Figure 3 the compression is generally referred to by arrows B, B'. In another embodiment of the present invention said matrix material is consolidated as such, without any specific compression stage, to form said boards. This may especially be the case when using a concrete or gypsum material for said matrix material . The matrix material may be vibrated in order to achieve a more compact structure, and reinforcement may be arranged e.g. during the distribution process or in a separate step, as known per se .

Figures 4 and 5 show examples of favorable arrangements of said interconnecting elements 4. In the embodiment according to Figure 4 said element 4 comprises an intermediate web portion 3 with attachment means at the outer ends thereof. The attachment means are provided by tongue- or finger- like protrusions being arranged in groups or pairs and extending generally in opposite orthogonal directions, so as to form said attachment portions 2, 2a. As shown in Figure 4 the direction of said protrusions 2, 2a preferably, at least in each respective end portion, slightly divert from the right angle and suitably in opposite directions. A pressing operation will force said portions 2, 2a to slightly bend in said matrix material 11, 11a to extend in different directions therein. Since said intermediate portion 3 will perform the function of a web portion in a conventional stud, said portion 3 should be dimensioned in an according manner, bearing in mind that said portion 3 later will be forced to bend, at least in the area 15 where said attachment portions 2, 2a connect to said intermediate portion 3. Said portion 3 may further comprise apertures 16 or the like, as well as special portions 17 comprising e.g. a different material, for obtaining desired fire- or sound-protection or the like properties.

Figure 5, correspondingly, shows an embodiment wherein said tongue- or finger-like attachment portions comprise tongues 2, 2a which are punched out in a flange- like attachment means 18, which in the finished structure will remain essentially flat against an inner surface of a respective one of said opposite boards. In order to facilitate the bending up of said intermediate portion 3 and for ascertaining that said bending takes place in a defined and desired manner, successive preferably elongated apertures and/or other indentations 19 or the like formations can be arranged in said element 4 at the border between the web portion 3 and the attachment means 18. In the embodiment shown in Figure 5 the tongues or fingers 2 on one side are more numerous than those at the other side. This type of interconnecting element 4 fulfills a double purpose. First said elements 4 will act as interconnecting means in accordance with the invention. A second purpose is to arrange, especially in structures used for bottom floors, roofs or the like, where expansion differences due e.g. to different humidity conditions may appear, provisions such that these matters can be coped with using said flange 18 and said tongues 2 connected thereto also as an element which in a "stressed-skin" element manner takes deflection forces due to said humidity conditions.

Figure 6 shows an embodiment wherein more than two layers of matrix material are arranged for forming boards 1, la, lb, said boards 1, la, lb being interconnected in pairs by interconnecting elements 4, 4a. In this embodiment a structure is achieved which comprises two outer boards 1 and la as well as an intermediate board lb. Figure 7 shows how such a structure may be arranged for providing a three- layer wall having an inner wall board 1 and an outermost wall board la. The outermost surfaces 9 of both boards have the intended surface pro^¬ perties of the constructional wall. Between said outermost boards 1, la there is arranged a third board lb which provides two separate spaces 6, 6a between said boards 1, la and lb. The inner one 6 of said spaces is used, in a conventional manner, for insulation 20 or the like, and here said boards 1 and lb preferably comprise only one interconnecting element 4. This enables slightly bending out said board 1 (shown in phantom) which facilitates the application of an insulation material 8 in said space 6 between said boards 1 and lb.

Referring to Figure 6 a further advantage is gained when the appropriate release material in this embodiment simultaneously provides a vapor barrier, in which case said material suitably comprises a plastic film 13b. Said vapor barrier 13b will suitably be clamped between the inner surface of said board 1 and optional reinforcement elements 21 (see Figure 7) running in a transversal direction in relation to said interconnecting elements 4. In most cases the matrix material 11, lla, lib in each layer will be essentially identical, but in some embodiments the materials in different layers is adapted for the special purpose of the respective layer. Thus, e.g. the innermost layer 11 may be of a material giving an appropriate resistance to vapor penetration, fire or the like, e.g. a board based on an impermeable resin material, concrete or the like. Other layers, e.g. board lb may act as a windboard permitting humidity to pass from said insulation 20 to said space 6a between said board lb and said outermost board la which, in turn, may act as a pure rain barrier. Here said space 6a will act for ventilation purposes in a manner known per se . Thus, said boards may comprise different matrix materials suitable for achieving the desired properties in the finished structure .

Further, referring to Figure 7 there is shown an arrangement wherein said boards la, lb actually are forced apart in an essentially parallel manner, and here any intermediate element 4a will be of a construction permitting a bending or folding also at a central line 22. This line favorably comprises one or several rows of said apertures 19, imprints or the like formation facilitating the bending at an appropriate point. In this embodiment said interconnecting element 4 initially is folded along said line so that said tongue- or finger- like attachment portions will be located essentially opposite with respect to each other.

Figure 8 shows the use of the inventive structure in a building. Here a floor structure 22 comprises upper and lower boards 1, la interconnected by an interconnecting element 4 having a perforated web portion 3. At both edges of said web portion attachment flanges 18 are arranged, said flanges 18 including rows of tongues 2 suitably punched out from each flange 18 to extend into said boards 1, la. The lower one of said flanges 18 preferably has an increased number of tongues 2 in order to reinforce the floor structure against deflection due e.g. to different moisture conditions inside and outside the building. The floor structure may further comprise separate reinforcing flanges 21 attached in the same manner as said interconnecting elements 4, which flanges 21 are bent up and fixed using any appropriate fixing means 23 such as screws or the like. A wall portion, e.g. a structure as shown in Figures 6 and 7 is then attached to said floor portion using e.g. fastening means 24 attached to appropriate wall boards 1, lb in a corresponding manner.

In general terms the invention gives a quite new type of structure which is easy to manufacture also using simple technology, which saves labor and which, due to a very firm attachment between the boards and the interconnecting element, acts as a stud or the like. Due to this firm attachment where, considered from a constructor's point of view, the applicable forces highly exceed the attachment forces possible e.g. in a conventional screw attachment, a considerable amount of material may also be saved, in comparison with the prior art. Thus, the interconnecting elements 4 may be made of sheet material, e.g. steel or the like, which is thinner than in conventional studs. The respective intermediate web portion 3 may further comprise holes 16 or the like, which reduces heat and/or sound transfer and also facilitate the arrangement of pipings or the like in addition to saving material. On the other hand, if an arrangement according to the invention is used as a permanent formwork, the space between the boards 1, la may be filled with concrete, while the outer surfaces may serve as the final- wall surface. Here holes in the intermediate web portion will permit the insertion of reinforcement bars (not shown) used for reinforcing the concrete. In addition to the above favorable features the inventive structure is especially easy to assemble. It can also easily be disassembled and stored.

Above some favorable embodiments have been disclosed as examples only, and it should be understood that the invention can be altered in many other ways within the scope of the appended claims.

Claims

1. A method for manufacturing board-like essentially flat composite structures of a matrix material by subjecting said material to a consolidation process, c h a r a c t e r i z e d in said method further comprising the steps of a) distributing a first layer (11) of said matrix material over at least one first forming area (12), for generating a first board- like structure body (1) b) providing at least one separate interconnecting element (4, 4a) of a deformable material, said element (4, 4a) comprising an intermediate web portion (3) and, connected thereto at outer portions thereof, attachment means including attachment portions (2, 2a) which at least at one of said outer portions are diverted from the direction of said web portion c) arranging on a surface of said distributed matrix material at least one layer of release material (13, 13a, 13b) d) arranging said separate interconnecting element (4, 4a) essentially flat at the surface of said first layer (11) of matrix material so that said intermediate web portion (3) is essentially parallel to said surface and said diverted attachment portion (s) (2, 2a) at said at least one outer portion extend, in an embedded manner, into said first matrix material layer (11) , the opposite attachment portio (s) being adapted to extend into a second layer

(11a) of matrix material constituting a second structure body (la, lb) of said composite structure, and e) subjecting said matrix material (11, 11a) and said embedded attachment portion to said consolidation process.

2. A method as defined in claim 1, c h a r a c t e r i z e d in casting said second layer (11a) of matrix material over said first layer (11) of matrix material and said inter^¬ connecting element (4, 4a), said opposite attachment portions

(2, 2a) of said element being diverted from said web portion (3) and extending into said second layer (11a) of matrix material, said release material (13, 13a, 13b) constituting a seam region (5) between said first and second layers (11 and 11a, respectively) of matrix material, and consolidating said second layer (11a) of matrix material suitably simultaneously with the consolidation of said first layer (11) of matrix material.

3. A method as defined in claim 1 or 2, c h a r a c t e r i z e d in casting several matrix material layers (11, 11a, lib) and consolidating at least some of said layers simultaneously, an interconnecting element (4, 4a) being arranged between each of said layers (11, 11a, lib) and corresponding release material (13, 13a, 13b) being arranged to constitute a respective seam region (5) between each of said matrix material layers (11, 11a, lib).

4. A method as defined in any one claims 1 to 3, c h a r a c t e r i z e d in consolidating at least one of said matrix material layers (11, 11a, lib) as a separate process, interconnecting means (4, 4a) and preferably also release material

(13, 13a, 13b) being arranged at at least one surface thereof.

5. A method as defined in any one of claims 1 to 4 , c h a r a c t e r i z e d in said consolidation process including the compressing of a matrix material comprising at least one fibre component and at least one setting component, said setting component being subjected to a hardening process.

6. An essentially flat composite structure comprising at least two opposite boards (1, la, lb) , each two of such boards being interconnected by an interconnecting element (4, 4a), respectively, outer portions (2, 2a) of said interconnecting element (s) (4, 4a) being attached to the matrix material (11, 11a, lib) of corresponding opposite boards (1, la, lb), c h a r a c t e r i z e d in that at least a web portion (3) of said interconnecting element (s) (4, 4a) extending, during the manufacture of said composite structure, essentially in the direction of a seam region (5) provided between closely adjacent opposite boards (1, la, lb), said outer portions of said interconnecting element (s) (4, 4a) comprising attachment means (2, 2a) attached, respectively, to adjacent opposite inner surfaces (8) of said opposite boards (1, la, lb) at said seam region (5) , said opposite boards (1, la, lb) being adapted to mutual detachment by increasing the spacing therebetween, said detachment being limited by the extent of said web portion (3) .

7. A structure as defined in claim 6, c h a r a c t e r i z e d in that at least one second one (la, lb) of said opposite boards (1, la, lb) being cast directly against at least one layer of release material (13, 13a, 13b) arranged at a surface (8) of a first one (1, lb) of said opposite boards (1, la, lb) .

8. A structure as defined in claims 6 or 7, c h a r a c t e r i z e d in that essentially tongue- or finger-like attachment portions (2, 2a) of said attachment means extend essentially transversely with respect to said seam region (5) and in opposite directions at said outer portions, respectively, thus extending through said inner surfaces (8) in an embedded manner into the matrix material (11, 11a, lib) of said opposite boards (1, la, lb) .

9. A structure as defined in any one of claims 6 to 8 , c h a - r a c t e r i z e d in at least one of said opposite boards (1, la, lb) comprising a compressed fibre structure.

10. A structure as defined in any one of claim 6 to 9, c h a r a c t e r i z e d in at least one layer of said release material (13b) constituting a vapor barrier or the like struc^¬ tural element in the final structure.

11. A structure as defined in claims 6 to 10, c h a r a c t e r i z e d in that at least one of said opposite boards (1, la, lb) comprise opposite especially finished edges (10) , preferably the parts of a groove-and-tongue joint.

12. An interconnecting element (4, 4a) adapted to be arranged in an essentially -board-like composite structure, between opposite boards (1, la, lb) and capable of lying essentially flat in a seam region (5) provided between opposite inner board surfaces (8) during the manufacturing of said structure, c h a r a c t e r i z e d in that said interconnecting element (4, 4a) comprises an essentially flat intermediate web portion (3) and, at two outer portions thereof, attachment means comprising attachment portions (2, 2a) adapted to divert, at said outer portions respectively, in opposite and essentially transversal directions with respect to said intermediate web portion (3), said interconnecting element (4, 4a) being manufactured of deformable material and adapted to bend, in the vicinity of said attachment means and after inclusion of said attachment portions (2, 2a) into the matrix material (11, 11a, lib) of said structure, into a direction which is essentially transverse to said opposite inner surfaces (8) of said boards (1, la, lb) .

13. An element as defined in claim 12, c h a r a c t e r i z e d in said intermediate web portion (3) having an elongated shape of a preferably sheet-like general configuration and having successive attachment portions, suitably groups or pairs of tongue- or finger-like means (2, 2a) arranged in said attachment means, the tongue- or finger- like means (2, 2a) in each such group or pair suitably being capable of diverting in slightly different directions.

14. An element as defined in claim 12 or 13, c h a r a c t e r i z e d in said web portion (3) comprising preferably elongated apertures (18) and/or thinned portions to facilitate said bending.

15. An element as defined in claim 12 to 14, for use preferably in connection with a manufacturing process including consolidation of matrix material (11, 11a, lib) constituting said boards (1, la, lb) , c h a r a c t e r i z e d in that said interconnecting element (4, 4a) further comprises a sheet - like release material (13, 13a, 13b), preferably paper, plastic or the like, arranged at at least one side of said interconnecting element (4, 4a), said attachment portion(s) (2, 2a) of said attachment means extending through said release material (13, 13a, 13b).

16. A method for erecting essentially flat structures such as walls, floors, ceilings and the like, said structures comprising at least two opposite boards (1, la, lb) or the like elements being interconnected by at least one interconnecting element (4, 4a), opposite attachment portions (2, 2a) of said interconnecting element being attached in the material of said boards (1, la, lb) , respectively, c h a r a c t e r i z e d in providing said interconnecting element (4, 4a) to extend in the direction of a seam region (5) between adjacent board elements (1, la, lb), forcing said adjacent opposite boards (1, la, lb) to mutually depart at said seam region (5), thereby forcing said interconnecting element (s) (4, 4a) or intermediate portions (3) thereof to bend and to extend essentially transversely to said seam region (5) .

17. A method as defined in claim 16, c h a r a c t e r i z e d in attaching at least some of said board elements (1, la) to adjacent such elements (1, la) and/or to external structures.