GB2367308A - Prefabricated form for constructing walls - Google Patents

Abstract

A prefabricated form for use in the construction of poured concrete walls comprises opposed sheets of extruded foamed polystyrene forming internal and external insulating panels <B>4, 5</B>. The panels <B>4, 5</B> are held in spaced relation by wall ties <B>10</B> comprising Z-shaped strips of galvanised mild steel having end flanges <B>10b</B> bounding a central web <B>10a</B>. The ties are slotted vertically into upper and lower horizontal edges of the panels <B>4, 5</B> and the web <B>10a</B> extend in opposite directions to form a triangulated space frame in combination with the panels <B>4, 5</B>. The webs <B>10a</B> may be interconnected horizontally and vertically by reinforcing rods or wires to provide a form as a complete, prefabricated, transportable wall section ready to receive poured concrete.

Description

2367308 IMPROVEMENTS IN AND RELATING TO BUILDING CONSTRUCTIONS, AND

BUILDING ELEMENTS FOR USE THEREIN This invention concerns improvements in and relating to building constructions, and building elements for use there in.

In the construction of modem buildings, it is becoming increasingly necessary to save time and cost by reducing to a minimum the fabrication required on-site in relation to the construction of elements such as the walls of a building.

It has, for example, being proposed to form a building with walls of cast concrete, by providing concrete shuttering that comprises building elements of an insulating material that will remain in place following the casting of the concrete wall, in order to form insulating layers that become interposed between the concrete wall and any external cladding, or decorative finish applied to the internal wall.

In one known construction, for example, form work into which concrete is to be poured is constructed from blocks of expanded polystyrene that are held in spaced relation by ties formed of injection moulded synthetic plastics material, the ties being inserted into slots preformed in the expanded polystyrene blocks, in order to hold the latter in the required position during pouring of the concrete. Upon setting of the concrete wall the plastic ties present exposed surfaces that can be used to receive fastenings for securing external cladding over the wall surface presented by the expanded polystyrene blocks between which the concrete has been poured.

The prior arrangements present a number of disadvantages, however, and there is a requirement for a building system that would enable concrete form work to be delivered to the building site as prefabricated elements, possibly in the form of complete prefabricated wall sections that are fully prepared to receive poured concrete.

In accordance with one aspect of the invention, a tie for use in securing moulding forms in spaced parallel relationship comprises an angle section of suitable I sheet metal and includes a central web bounded by two end-flanges that preferably extend in parallel planes.

Moulding forms comprising sheets of suitably rigid insulating material can then be held in spaced relation by providing, at edges of the sheets, angled slots that extend partially through the thickness of the sheet material in such a manner that an end flange of the sheet metal tie can be slotted into an edge of the sheet material at a point between its opposite faces, with the central web of the tie extending from one face of the sheet via another adjoining slot.

By slotting the angled sheet metal ties vertically into slots at upper and lower edges of spaced parallel sheets of material, the resulting unit can be made to form a substantially rigid self supporting space frame incorporating the two parallel sheets of insulating material in positions that are aligned in a suitable manner to receive poured concrete.

In one preferred embodiment of the invention, the insulating sheets are formed of extruded closed-cell foamed polystyrene that is of known type conventionally available for use as insulating sheets in the building industry. Such sheets are available in tongued and grooved form for interengagement with one another to cover a surface area larger than the individual sheets.

It has been found that by utilising sheets of extruded foamed polystyrene and ties of galvanised mild steel sheet, the ties become frictionally engaged in the slots pre-cut in the polystyrene sheets sufficiently to hold the components together as a self supporting structure.

Preferably the sheet metal ties are of Z-shaped construction. with the end flanges extending parallel to the planes of the polystyrene sheets and the central web of the ties extending obliquely between the spaced parallel sheets. By inserting ties in anti-symnietrical manner, a triangulated or trapezoidal structure is formed, that is particularly rigid for storage and transport.

The sheet metal ties may serve for the attachment of metal reinforcing rods or wires that are to be embedded in the concrete wall, and by welding reinforcing rods between metal ties of separately-fonned space- frame elements, a complete and self supporting wall may be constructed from stacked panels, so that forms for complete building walls may be delivered to a site as a single unit. Such wall units may be prefabricated with ready-made openings for incorporation of doors and windows, and the sheet metal ties in the region of door and window openings may serve to support reinforcing rods that are welded in place in the region of the lintels of the doors and windows, to avoid the need for fabrication of separate lintels during the building process.

The invention is illustrated by way of example in the accompanying drawings, in which:

Figure I is a sectional elevation illustrating the section of a wall of a building constructed in accordance with the invention; Figure 2 is a horizontal section through a comer of a building constructed with walls in accordance with the present invention, illustrating the positions of wall-ties; Figure 3 is a plan view of a sheet metal tie in accordance with the invention; Figure 4 is a side elevation of the tie of Fig. 3, taken in the direction of the arrow X of Fig. 3; Figure 5 is a side elevation of a wall tie as shown in Figs. 3 and 4, with attached reinforcing rods; and Figure 6 is a plan view of the arrangement shown in Fig. 5.

Referring to the drawings, there is shown in Fig. I a section of a building wall comprising a footing (1) upon which is supported a building wall (2) which is formed from cast concrete (3) that has been poured between form work provided by opposed internal and external insulating panels (4 and 5) held in place by wall ties (not shown) to define the space into which the concrete is poured. As shown in the drawing the internal and external surfaces of the insulating panels (4 and 5) are provided with suitable cladding (6).

3 As also shown in Fig. 1, the form work for reception of the poured concrete is provided by a series of stacked panels that inter-engage one another by means of tongue and groove connections. The panels are a proprietary tongued and grooved insulation board formed of extruded closed-cell foamed polystyrene, and are conventionally available in the building industry.

Referring to Fig. 2, in which the same reference numerals indicate the same components as in Fig. 1, it will be seen that the internal and external panels (4 and 5) are held in spaced relationship by means of wall ties (10) to be described in more detail below. Each wall tie comprises a Z-shaped strip of galvanised mild steel comprising a central web (10a) bounded by two end flanges (10b). A series of slots corresponding in shape to the profile of the tie (10) are cut vertically into the horizontal edges of the panels (4 and 5), one slot extending obliquely through the thickness of the panel from an internal face thereof, and terminating at a point intermediate the opposite faces of the panel, an d a second slot extending from the internal end of the first slot and in the plane of the panel.

Thus, individual building elements formed by two opposed panels (4 and 5) can be prepared by slotting a series of the sheet metal ties (10) into the horizontal edges of aligned panels, so that the central web (I Oa) and the end flanges (I Ob) make frictional engagement in the slots of the panels, with the ties (10) located at the upper and lower horizontal edges of the panels.

As can be seen from Fig. 2, ties (10) are arranged above one another at the upper and lower edges of each pair of panels, but are located in antisymmetrical arrangement, so that the webs (10a) of the lower panel extend as shown in broken lines in Fig. 2. This arrangement has the advantage that the oblique webs of the upper and lower wall ties effectively form a triangulated space frame that holds the opposed panels from moving relatively to one another in their own plane. The spaces defined between the webs of the upper and lower ties also serve, conveniently, to locate reinforcing rods that may extend vertically within the space between the panels.

Referring to Figs. 3 and 4, the form of an individual wall tie (10) can be seen in more detail, and it will be seen that the edges of the web (10a) may be provided 4 with a series of recesses (I Oc) that may serve to receive concrete reinforcing rods (12) to be embedded in poured concrete. The reinforcing rods may optionally either be welded to the webs (10a), or merely rested in the corresponding recesses (10c) at the time when concrete is poured. The reinforcing rods (12) are particularly appropriate at positions where lintels are to be formed at doors or windows. Apertures (10d) may optionally be provided in the webs (I Oa), as shown in Fig. 4.

Referring to Figs. 5 and 6, there is shown a composite element formed by a sheet metal tie (10) and pair of reinforcing rods (14) welded to the web (10a) of the tie. As shown in Fig. 5, the upper ends (14a) of the reinforcing rods (14) extend above the upper edge of the web (10a) for the purpose to be described below. The reinforcing rods (14) are also slightly splayed in the downward direction, as shown in the drawing.

In the production of an individual form work element according to the invention, insulating panels (4 and 5) are located in spaced relation, and individual sheet metal ties as shown in Figs. 3 and 4 are slotted into the lower edges of the spaced panels in the manner shown in Fig. 2. Composite elements as shown in Figs. 5 and 6 are then slotted into the upper edges of the panels in such a manner that the reinforcing rods (14) extend downwardly and engage around the webs (10a) of ties (10) located directly below the upper ties but extending in anti-symmetrical relationship thereto as described above. The splayed arrangement of the reinforcing rods (14) ensures that the free ends thereof engage upon the connect sides of the flange of the lower tie, and the reinforcing rods (14) are then welded to the lower ties in order to lock the upper and lower ties (10) into the upper and lower edges of the insulation panels. A complete unit is thus fon-ned.

In order to build a complete prefabricated wall section, the insulating panels (4 and 5) can be stacked one above the other as shown in Fig. I in which case the upper ends (14a) of reinforcing rods located in each lower panel are then welded to the flanges (10a) of ties at the lower edge of the panel above, in order to secure the complete structure together as a unit. Horizontally arranged panels can also be located relatively to one another by welding horizontally reinforcing rods across the edges of ties in adjacent panels, the reinforcing rods being located as shown in Fig. 4.

An arrangement in accordance with the invention, has significant advantages over known building arrangements. The selection of sheet metal ties for slotted insertion into the edges of insulation panels of extruded foamed polystyrene provides a particularly attractive construction, although, of course, other equivalent materials could be used for a similar construction. The, fact that the sheet metal ties do not extend fully through the thickness of the insulation panels avoids the formation of cold spots as there is no bridge for the conduction of heat between the inner and outer surfaces of the wall. Nevertheless, the end flanges (I Ob) of the tie that are embedded within the insulation material conveniently form attachment points for receiving fastening screws that may be used to secure cladding to the faces of the insulating panels.

The capability of securing reinforcing rods to the sheet metal ties by welding also enables the construction of prefabricated form work of larger size than has previously been feasible, thus enabling a prefabrication of complete wall-sections offsite.

Tbus, a novel and significantly improved building system is provided.

It will be appreciated that various modifications may be made to the system as described without departing from the scope of the invention. In particular, the metal tie (10) can have shapes other than the Z-shape illustrated, and the insulation panels (4 and 5) may be made of materials other than foamed polystyrene, provided that the physical characteristics of the material are suitable for the purpose. The reinforcing rods (14) may be replaced by wires in appropriate circumstances.

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Claims (13)

1 A method for the construction of building elements, such as walls, by pouring castable material into formwork or shuttering comprised of spaced apart sheets of synthetic plastics insulating material said sheets being located in spaced relationship by means of ties, characterised in that said ties are provided in the form of angled sheet metal elements including a central web bounded by two end flanges, that said sheets of insulating material are provided, at edges thereof with angled slots that extend partially through the thickness of the sheet material and that said sheets are secured in spaced relation by slotting said elements into said angled slots whereby said end flanges each extend within one of said sheets and said central web extends between said sheets to retain them in spaced relation.

2. For use in the method of claim 1 a tie for securing moulding forms in spaced relation and comprising an angled sheet metal element including a central web bounded by two end flanges.

3. For use in the method of claim 1 a prefabricated moulding form comprising two opposed sheets of synthetic plastics insulating material held in spaced relation by means of metal ties in the form of angled sheet metal elements each comprising a central web bounded by two end flanges, a plurality of said metal ties engaging in slots formed in each of two opposite edges of each of said sheets, whereby respective edges of the two opposed sheets are held in spaced relation by the central webs of said ties said end flanges being accommodated within the thickness of said sheets.

4. A method, a tie or a prefabricated moulding form according to any one of claims 1-3, wherein the or each said angled sheet metal element is of Z-shaped section, comprising two spaced parallel end flanges arranged in facing relationship and interconnected by a central web extending from one edge of one end flange diagonally to the remote edge of the other end flange.

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5. A method according to claim 1 or 4, or a moulding form according to claim 3 or 4, wherein said Z-shaped metal elements are slotted vertically into upper and lower edges of said spaced insulating sheets, with the angled central webs of said elements extending in opposite directions such that the moulding form is reinforced in the manner of a triangulated or trapezoidal space frame.

6. A prefabricated moulding form according to any one of claims 3-5, wherein the central webs of ties at opposite edges of the form are interconnected by rods or wires to retain the ties in engagement with the respective edges of the said insulating sheets.

7. A prefabricated moulding form assembly comprising a plurality of moulding forms according to any one of claims 4-6, stacked vertically, the central webs of ties of the respective stacked forms being interconnected by rods or wires to retain the assembly as an integral unit.

8. A prefabricated moulding form assembly comprising a plurality of forms or assemblies according to any one of claims 4-7 located horizontally adjacent one another and interconnected by horizontally extending rods or wires secured to central webs of ties of adjacent forms or assemblies.

9. A prefabricated moulding form assembly according to claim 8 as appended to claim 7, wherein one or more apertures are provided to receive doors or windows, reinforcing rods being arranged to extend horizontally across ties of the assembly adjacent an aperture to provide reinforcement for a lintel.

10. A method according to any one of claims 1, 4 or 5 or a moulding form or moulding assembly according to any one of claims 3-9, wherein said sheets of insulating material comprise closed cell extruded polystyrene.

11. A method as claimed in claim 1, substantially as described herein.

12. A tie for use in the method of claim 1, substantially as described herein with reference to Fig. 3, Fig. 4 or Figs. 5 and 6 of the accompanying drawings.

8 13. A prefabricated moulding form substantially as described herein with reference to Figs. 1 and 2, Figs.

1-3, Figs. 1-4, or Figs. 1-6 of the accompanying drawings.

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