GB2357104A - Plastic screed rail - Google Patents

Abstract

A plastic screed rail [1] for use in the laying of concrete or other flowable material floors comprises a base [2] which supports a vertical member [5]. The member [5] is a snap-fit into the groove [4], in the base [2], formed by the ridge [3]. Slots [11] or apertures are provided for the location of concrete reinforcement mesh. In another embodiment, the base [2] and vertical member [5] are formed in one piece.

Description

2357104 A SHUTTERING DEVICE The present invention relates to a shuttering

device or formwork for use in laying concrete or other material floors which may be used as a levelling device for concrete or other material floors.

It is known when laying a domestic concrete floor, for example, for a sub-floor of hardcore to be first laid and compacted with a vibrating plate compacting device wherein it is attempted to get such hardcore layer as level as reasonably possible. If the floor is being laid in a hous, ''initially the hardcore may be laid to the level of a course of bricks although there is no guarantee that such bricks will necessarily be horizontal as settling may have occurred. Subsequently, a layer of sand is laid thereover to protect a subsequently laid water impervious membrane against damage which membrane is laid on top of the sand and folded upwardly at the edges and joins the walls at the damp course level or above. Subsequently, concrete is laid thereover but in order to contain the concrete and enable the upper surface to be levelled or flattened, short strips of wood are arranged in substantially parallel disposition and held in position by small mounds of sand or cement or formed as a frame and the concrete filled generally to the level of the upper surfaces thereof and then a levelling beam or crosspiece moved thereacross and the concrete tamped to remove air bubbles and to level the surface of the concrete to the upper surfaces of the strips of wood. Once done and the concrete is set or hardened a little, the strips of wood then have to be removed (as they would otherwise rot) and are relocated in an extension of their former position in mounds of concrete or the like and the levelling and tamping operation continued. It is not possible to drive securing wedges or pegs into the sub-floor or hardcore layer because such would penetrate the membrane and destroy the integrity of the waterproofing.

2 It will be appreciated that once an area of floor has been laid and tamped and the wood strips removed, it is not then possible to return to such region or to cross such until the concrete is set and hard. Also, considerable variations in thickness of concrete laid in this manner result which also results in an unevenness and an excessive use of material is some cases which is uneconomic.

Considerable labour is involved in the process and inaccuracies result and also increased costs arise from the unnecessary thicknesses of concrete level.

With domestic floors, a polystyrene insulation layer of perhaps 50 mrn will be provided above the membrane and then concrete of perhaps a mm, be located thereabove. For industrial floors, however, no insulation is required and the concrete is laid directly on the membrane and a steel reinforcing mesh may be located in the concrete spaced above the membrane.

According to the present invention a shuttering or levelling device for use in the laying of concrete or other flowable material floors comprises a base means which supports or is capable of supporting an elongate member or portion in an upwardly extending manner such that, in use, said member or portion may retain concrete or other material; the upper surface of said elongate member or portion being for supporting a concrete tamping crosspiece or levelling beam to be also supported on a similar parallel device; said base means and elongate means being formed of plastics material or other non-degradable or non-rotting material.

Preferably the shuttering or levelling device will be integrally formed or one piece although for ease of transport/storage such may be formed from two interconnectable parts and detachably dismantlable for storage/transport.

3 Preferably detent or other catch or snap-fit means will be provided to keep the parts together in use.

Preferably the base means will be of a width (transverse to the direction of elongate extension and to the upwardly extending member) such as to provide stable support for said upwardly extending member even when the space between adjacent pairs of devices is filled with concrete. For example, preferably the width of the base means will be at least equal to the height of the elongate member.

For example, the base means may comprise an elongate plank-like member with a groove or channel or other apertured means running centrally along the length for receiving an upwardly extending elongate linear plank like, wall-forming member and preferably such base means and wall-forming member will be of plastics material or other non-degradable material so that it can be left in the concrete after the use and set therein. The base means and upwardly extending member may be apertured in any manner as desired to save weight and/or material but will have to be sufficiently rigid and stable for the laying operation.

In use, at least two shuttering or levelling devices are arranged in horizontal disposition onfop of a water impervious membrane in parallel disposition and across the width of the floor to be laid. Normally more than two of such shuttering or levelling devices will be provided and aligned in line and possibly provided with interconnections forming the line. Concrete will be laid between each pair of parallel devices possibly first with the provision of thermal insulating slabs for domestic use and the concrete will be laid to approximately the upper surface of the wall-like upward elongate member whereupon a levelling beam will be used moving along the members in known manner. After use, the shuttering or levelling devices are left in situ in the concrete and can also be used to provide the support for cross planks e.g. to 4 provide for further access or for further levelling or surfacing operations even prior to setting of the concrete.

Preferably, the shuttering or levelling device is one piece and of inverted T- or I-cross section and where storage and transport is no problem, preferably an integrally-formed member. Preferably, the upwardly extending elongate wall-like portion will have slots or other apertures spaced for receiving the ends or parts of reinforcing mesh.

The shuttering or levelling device has to be sufficiently rigid to take the necessary loads and may be of lengths of say 4 to 5 metres.

In a preferred embodiment water impervious membrane will be provided in strips between adjacent pairs of levelling devices and may be located by means of adhesive and may be provided in a double thickness layer to reduce any risk of capillary action. Preferably double-sided self adhesive tape is provided on the upper surfaces of the webs of the inverted T piece.

It is possible that when laying a floor, a pair of such shuttering or levelling devices may be adjacently located to provide a ducting within the floor in which case no concrete will be provided in the region therebetween.

Preferably, the upwardly extending wall-like member will be a press fit or otherwise securable or connectable to the base means.

Caps may be provided for the upper ends of slots when extending to the upper surface of the elongate member to enable the tamping or levelling beam to be moved thereover without falling therein or catching thereon.

Also according to the present invention a method of laying a concrete floor comprises providing a hardcore or other generally flat supporting layer of material, standing at least two or a pair of shuttering or levelling devices of plastics material or other non-degradable material, in parallel or substantially parallel disposition, feeding concrete to the space between the devices and tamping the concrete with a tamping board or crosspiece laid across the devices and allowing the concrete to set with the devices in position.

Preferably, a plurality of pairs of parallel devices are located in position and aligned. Preferably a reinforcing mesh is located and held suspended between the top of the device and its base prior to feeding of the concrete or other partial feed.

The present invention provides a device which enables the user to obtain a level and flat floor, to gain access to ail areas of floor whilst concrete/screed is still wet. The invention also allows for final trowel finish, by hand or power float, and also enables the use of earlier concreted floor to be retained for access and may be used in both domestic and industrial situations. Also the device of the invention is adapted so as to be able to incorporate reinforcings for industrial use and insulation in domestic use.

Additionally, the invention may facilitate laying both internally and externally e.g. driveways, footpaths, lawns etc., and is highly suitable for D.I.Y. market.

The device may be used for purposes other than laying concrete floors, e. g.

as path edgings or like in gardens.

The invention will be described further, by way of example, with reference to the accompany drawings, in which:- Fig. I is a perspective view from one end of a preferred embodiment of shuttering or levelling device; Fig. 1A is a view of a short length of a device similar to that of Fig. 1 with fixing peg; Fig. 1 B is an end elevation of the device of Fig. 1A; Fig. 2 is a schematic elevation of two levelling devices in situ in concrete and a levelling crosspiece or tamping board supported thereby; 6 Fig. 3 is a schematic part cut-away view of an intermediate stage in laying a concrete floor including insulation panels and prior to location of any reinforcement mesh and prior to pouring-in the concrete, Fig. 4 is a fragmentary perspective view of the levelling device showing the location of a reinforcement mesh; and Fig. 5 is a schematic section through a laid concrete floor illustrating two of the levelling devices and the thermal insulation.

In Figs. 1-3 a preferred embodiment of a concrete floor shuttering or levelling device 1 is illustrated and comprises an elongate base means or member 2 of non-degradable plastics material of somewhat plank-like outline and of perhaps 4 to 5 metres length and of a width of, for example, 15 cm to provide stability and a thickness of, for example, 8 mm. A central elongate ridge 3 is provided running the length of the base means 2 and forming a channel 4 in which the lower edge of an upwardly extending elongate wall like member 5 is securedly locatable in press-fit manner and retainable therein. The member 5, in the example, is 15 cm high and 8 mm thick. The base means 2 thus has two lateral parts 6,7, of approximately 7.5 cm, which stabley support the elongate wall member 5 and may each have adhesive applied thereto for securing of strips of impervious membrane 17 therealong e.g. by means of a double sided tape 6'. The elongate member 5 extends along the length of the base means 2 and preferably vertically therefrom and of a height e.g. 15 cm selected compatible with the intended depth of concrete.

The upper edge 8 of elongate wall member 5 is straight and normally disposed generally horizontally and planar and along which a tamping board 9 with handles 10 is displaceable to tamp the concrete when located between a pair of devices.

Sometimes it is desired to reinforce the concrete by means of a steel mesh 12 in the middle of the concrete layer and this can be achieved with the 7 device 1 of the invention by providing a plurality of slots 11 (only one shown in Fig. 1) spaced corresponding to the mesh pieces (e.g. at 20 cm centres as illustrated in Fig. 1A) and generally into half the height of member 5 so as to support the mesh between two or more members 5. Non-degradable fixing pegs 11 may be provided for securing the reinforcing mesh parts which are cut to length to finish flush with the floor slabs or top of member 5. Caps may, alternatively, be provided (not shown) e.g. as inverted U-shaped members, to close off the upper ends of the slots once the mesh is located or otherwise, to ensure there is no obstruction to the tamping board. It is also envisaged where no mesh is being used, the member 5 may be inverted so that the edge 8 locates in channel 4 and edge 8' is at the top.

Normally a plurality of devices 1 will be arranged in parallel straight lines as indicated in Fig. 3 prior to laying of the concrete 15.

In use, a hardcore layer 15 is laid and compacted and then where a water impervious membrane 17 is being used, a "blinding" layer of sand 18 is laid and levelled to protect the membrane 17 from projections of the hardcore 16. The membrane 17 is then laid thereover unless, as in Figs. 3 and 5, it is preferred for the devices 1 to be laid on the sand and strips of membrane laid between the devices and secured by double-sided adhesive tape onto the parts 6,7 and preferably with doubled layers extending up the members 5 to prevent any compulsion action. The parallel rows of aligned devices 1 are initially laid end to end, possibly interconnected at their adjacent ends by means (not shown).

In domestic or other situations, a thermal insulation layer 19 e.g.

polystyrene thermal insulation slabs such as sold under the name "Jabolite", may optionally be provided between devices 1 of perhaps 5 cm height and then concrete 15 laid thereover and tamped to a layer of approximately 10 cm with board 9. Alternatively, the mesh 12 may first be located supported by members 5 and the concrete then poured in prior to tamping.

8 It will be appreciated that, unlike hitherto, the shuttering devices 1 are intended to be left in place after setting.

- -1 9

Claims (23)

1 A shuttering device for use in the laying of concrete or other flowable material floors comprises a base means which supports or is capable of supporting an elongate member or portion in an upwardly extending manner so as, in use, said member or portion retains concrete or other material; the upper surface of said elongate member or portion being for supporting a tamping crosspiece or levelling beam to be also supported in use on a similar, parallel device; said base means and elongate means being. formed of plastics material or other non-degradable material.

2. A device as claimed in claim 1, which is integrally formed or one piece.

3. A device as claimed in claim 1, in which, for ease of transport/storage said device is formed from two interconnectable parts comprising said base means of said elongate member which are detachably dismantlable for storage/transport.

4. A device as claimed in claim 3, in which a detent or other catch or snap-fit means are provided to keep the parts together in use.

5. A device as claimed in at least claim 1, in which the base means comprises an elongate plank-like member with a groove or channel or other apertured means for receiving the elongate member which is a linear, plank like wall-forming member.

6. A device as claimed in claim 5, in which said base means and wall forming member are of plastics material or other non-degradable material so that such can be left in the concrete after the use and set therein.

7. A device as claimed in any of claims 1 to 6, in which the base means and upwardly extending elongate member are apertured in any manner as desired to save weight andlor material whilst remaining sufficiently rigid and stable for the laying operation.

8. A device as claimed in any of claims 1 to 7, which is of inverted Tcross section or I-cross section.

9. A device as claimed in any of claims 1 to 8, in which the upwardly extending elongate wall-like member or portion has slots or other apertures for receiving the ends or parts of a concrete floor reinforcing mesh.

10. A device as claimed in any of claims 1 to 9, which is of a length of the region of 4 to 5 metres.

11. A device as claimed in any of claims 1 to 10, in which the height of the elongate member is in the region of 15 centimetres and the width of the base in the region of 15 centimetres.

12. A device as claimed in any of claims 1 to 11, in which strips of water impervious membrane are provided such that in use they may be laid in strips between adjacent pairs of levelling devices.

13. A device as claimed in claim 12, in which the strips may be located by means of adhesive.

14. A device as claimed in claims 12 or 13, in which the strips are provided in a double thickness layer to reduce any risk of capillary action.

15. A device as claimed in claim 14, in which a double-sided self adhesive tape is provided on the upper surfaces of base means on either side of the elongate member,

16. A device as claimed in any of claims 1 to 15, in which the upwardly extending wall-like member is a press fit or is otherwise securable or connectable to the base means.

17. A device as claimed in any of claims 1 to 16, in which the elongate upwardly extending member has apertures or slots extending from one side and spaced such as to receive and support parts of a mesh for reinforcing the concrete.

18. A device as claimed in claim 17, in which caps are provided for the slots when extending to the upper surface of the elongate member to enable the tamping or levelling beams to be moved thereover without failing therein or catching thereon.

19. A method of laying a concrete floor comprises providing a hardcore or other generally flat supporting layer of material, standing at least two or a pair of shuttering or levelling devices of plastics material or other non- degradable material, in parallel or substantially parallel disposition, feeding concrete to the space between the devices and tamping the concrete with a tamping board or crosspiece laid across the devices and allowing the concrete to set with the devices in position.

20. A method as claimed in claim 19, in which a plurality of pairs of parallel devices are located in position and aligned.

21. A method as claimed in claim 20, in which a reinforcing mesh is located and held suspended between the upper surface of the device and its base prior to feeding of the concrete or other partial feed.

22. A device substantially as herein described with reference to the accompanying drawings.

12

23. The use of at least two shuttering devices as claimed in any previous claim in laying a concrete floor.