GB2560741B

GB2560741B - Drainage apparatus

Info

Publication number: GB2560741B
Application number: GB1704603.8A
Authority: GB
Inventors: Ellis Howden Robert
Original assignee: GRASS CONCRETE Ltd
Current assignee: GRASS CONCRETE Ltd
Priority date: 2017-03-23
Filing date: 2017-03-23
Publication date: 2019-08-14
Anticipated expiration: 2037-03-23
Also published as: EP3601675A1; GB201704603D0; EP3601675B1; WO2018172778A1; GB2560741A

Description

Drainage apparatus

Technical Field of the Invention

The present invention relates to drainage apparatus and in particular apparatus for improving drainage in solid concrete paving.

Background to the Invention

Increasingly, regulation requires sustainable drainage systems (SuDS) to be installed, in order to reduce surface water run-off and thereby reduce the risk of flooding. This can be attained by using special solutions that deliberately have apertures in, through which grass can grow (for example the Grasscrete® line of products available from Grass Concrete Limited of West Yorkshire, UK).

Alternatively, more traditional paving (not intended to allow grass to grow through it) can be obtained by forming paving from relatively small blocks (say around 500cm2 in surface area) with relatively large gaps in between them. However, this solution is not suitable where concrete slabs, rather than smaller blocks, are used. Typical concrete slabs have a surface area in excess of 3000 cm2, being formed in sizes such as 60cm x 60cm (x 5cm depth), or 90cm x 60cm (x 5cm depth). In consequence large gaps are required, and still stormwater is concentrated in a relatively small area between the slabs.

Of course, this issue of surface water run-off is exacerbated further when even larger concrete slabs which may have dimensions ranging from around 500 x 500cm to 1000cm x 1000cm or more are cast on-site. At the edges of paving formed from such large concrete slabs that are cast on-site, dedicated drainage is typically provided, to collect surface water run-off and direct it to a sewer. Alternatively, or additionally, “slot drainage products” or “slot drains” are provided at intervals where concrete slabs meet, in order to collect surface run-off and direct it to a sewer. Large concrete slabs of this type, which are cast on-site, have a tendency to expand and contract with changes in temperature. In consequence, where the slabs meet, they are connected by expansion joints. These can for example be formed by flexible (compressible) board placed between the joints and covered with a sealant.

The present invention seeks to provide an improved drainage apparatus for concrete slabs.

Summary of the Invention

According to a first aspect of the invention, there is provided a kit of parts according to claim 1. The slot drain of the kit, being configured to expand and contract, is thus able to expand and contract in response to contraction and expansion of one or more adjacent concrete slabs.

Such a slot drain that effectively also comprises an expansion joint is capable of providing a synergistic dual function, operating both to allow expansion/contraction of concrete slab, and to collect surface run-off and direct it elsewhere.

The slot drain has a channel delimited by two opposing channel walls, the channel walls being resiliently biased apart. Each channel is located in use along the edge of a concrete slab, and the resilient bias allows the channel to expand and contract with the slab. The expansion joint has an expanded state when the adjacent concrete slab is contracted and a contracted state when the adjacent concrete slab is expanded.

The resilient bias may be provided by one or more resilient components arranged between the channel walls. Opposing resilient components may be provided on (the inside surfaces of) each channel wall, so as to abut one another. A plurality of resilient components may be spaced along each opposing channel wall. Each resilient component may be a pad formed of or comprising a resilient compressible material such as a synthetic rubber; a suitable type of which is Nitrile Butadiene. Each resilient component may be resiliently compressible by at least 1mm, at least 2mm or at least 2.5mm.

The slot drain may have a cover, having one or more apertures therein, for example a plurality of slits, or a grid of apertures, through which water can drain into the channel. The cover may be provided with further apertures for connection to the channel walls.

The cover may be provided in a rebate. The rebate may be provided in head pieces attached to the channel walls, or may be integral with the channel walls.

The rebate may be sized to provide a recess that supports the cover, but has edges that are wider than the cover in the expanded state (of the slot drain) and edges that are closer together, optionally touching the edges of the cover, in the contracted state (of the slot drain). The rebate may be sized to support the cover whilst expanding by at least 1mm, preferably at least 2mm. This would accommodate typical levels of expansion, even in quite large slabs. Even more preferably, the recess may be sized to support the cover over at least 3mm, at least 4mm, or at least 5mm of expansion/contraction.

The head pieces may be each associated with respective channel walls and may be provided with one or more resilient components arranged between them.

Each head piece may comprise connection means for connecting to a respective channel wall. Connection means may comprise a groove, into which the channel wall may engage. Opposing resilient components may be provided on each head piece, so as to abut one another. A plurality of resilient components may be spaced along each opposing head piece. Again, each resilient component may be a nitrile butadiene pad and each resilient component may be resiliently compressible by at least 1mm, at least 2mm or at least 2.5mm.

The slot drain may comprise a filter. This can prevent the slot drain from silting up. The filter may be provided underneath the cover. The filter may be supported on ledges on opposing channel walls, or ledges extending from opposing surfaces of each head piece.

Resilient components may be arranged beneath the flanges on the head pieces.

The filter may be provided with one or more lifting eyes. This can allow easy removal.

The slot drain may comprise end plates at each end of the channel. Each end plate may be attached to one or both channel walls and/or one or both head pieces by a resilient connection, for example double sided neoprene sponge tape. Alternatively, the end plates could be loosely fixed, for example by a loosely tightened screw, or screwed through slots, rather than holes.

The slot drain is provided with a plurality of apertures for connection to a plurality of pipes. The apertures are provided in one or both channel walls. A plurality of pipes may be attached to the slot drain, such that water may drain out of the slot drain into the pipes. The plurality of pipes may be arranged at the base of the slot drain and may be arranged to extend between downwardly depending portions of concrete slab. The plurality of pipes may be arranged on one or both sides of the slot drain.

The plurality of pipes may be spaced, optionally equally spaced, along the length of the slot drain. At least three, four or five pipes may be provided. The pipes may be attached by solvent welding, adhesives, or any other known techniques.

Each pipe may be perforated, such that water may drain out of the pipe directly beneath a concrete slab. This provides a much more sustainable drainage system, as the water is directed across a larger area beneath, not just beside, the concrete slab. Alternatively, the pipes may not be perforated, in which case they may be plumbed to a water harvesting system.

Each slot drain may comprise engagement means for engaging with a “former” or mould.

The engagement means may comprise a platform on which the mould may be arranged, and optionally adhered to, for example fixed by double sided tape.

The engagement means may be arranged towards the base of the slot drain, but above the apertures for the pipes.

The engagement means may be arranged on both sides of the slot drain. The engagement means may extend outwards from an outside surface of one or both channel walls.

According to another aspect of the invention, there is provided a concrete slab according to claim 18. The concrete slab may be provided with downwardly depending portions, between which pipes extend.

The mould may be formed of moulded plastics.

The mould is provided with recesses to define downwardly depending portions of concrete. The recesses are so arranged as to extend between apertures in, and/or pipes extending from the slot drain.

The recesses may be arranged in a grid. Each recess may be substantially square. Each substantially square recess may have substantially straight edges at the top and may have straight edges at the base. Alternatively it may have curved edges at the base. Each curved edge may curve inward (i.e. to be closer to the centre of the recess in the middle, than at the corners). This curvature can provide some stiffness to resist live concrete load on the side walls of the formers. The sides of the recesses may be corrugated. Corrugation would further aid stiffness. On the other hand, if the additional stiffening can be dispensed with and the recesses provided with no corrugations and no curves, a greater percentage of concrete will be in contact with the base.

Each recess may be at least 20mm deep, more preferably at least 40mm deep, for example at least 50mm deep.

The slot drain may be at least 50cm long, more preferably at least 75 cm long and more preferably still at least lm long.

The kit may further comprise sleeves (e.g. rubber or elastomeric sleeves) to join a plurality of moulds.

The kit of parts may comprise a plurality of slot drains according to the invention (optionally including any optional features or any combination of optional features) and a plurality of moulds for moulding at least the base of concrete slabs.

According to another aspect of the invention, there is provided a method of forming concrete paving according to claim 24.

The method may comprise arranging the slot drain between concrete slabs.

The method may further comprise arranging a mould (or “former”) adjacent to the slot drain and pouring concrete into the mould to form a concrete slab. The method may further comprise arranging a plurality of formers adjacent to the slot drain and pouring concrete into the mould to form concrete slab.

The method may further comprise providing a reinforcement, such as a metal mesh on the mould. The method may further comprise spacing the metal mesh from the mould with spacers.

The method may comprise pouring the concrete to create a slab having a depth of at least 100mm from the base of the mould, or at least 100mm from the top of the mould. Alternatively the method may comprise pouring the concrete to create a slab having a depth of at least 150mm, 200mm, or 250mm from the base of the mould, or at least 150mm, 200mm, or 250mm from the top of the mould.

Detailed Description of the Invention

In order that the invention may be more clearly understood an embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows a perspective view of a slot drain according to the invention;

Figure 2 shows a lateral cross section through the slot drain of figure 1;

Figure 3 shows a side view of the slot drain of figures 1 and 2;

Figure 4 shows a plan view of the slot drain of figures 1 to 3;

Figure 5 shows an end-section view of a slot drain of figures 1 to 4 in use with a mould and a concrete slab;

Figure 6 shows an isometric top-down section view of the slot drain, mould and concrete slab of figure 5;

Figure 7 shows an isometric bottom-up section view of the slot drain mould and concrete slab of figures 1 to 6;

Figure 8a shows a lateral cross section through the slot drain of figures 1 to 5 in the compressed condition;

Figure 8b shows a lateral cross section through the slot drain of figures 1 to 5 in the expanded condition;

Figure 9a shows an isometric view of the outside of a channel wall of the slot drain of figures 1 to 5;

Figure 9b shows an isometric view of the inside of a channel wall of the slot drain of figures 1 to 5;

Figure 10a shows an isometric view of the inside of a head piece of the slot drain of figures 1 to 5;

Figure 10b shows an isometric view of the outside of a head piece of the slot drain of figures 1 to 5;

Figure 11 shows an isometric view of an end cap of the slot drain of figures 1 to 5;

Figure 12 shows an isometric view of the filter of the slot drain of figures 1 to 5;

Figure 13 shows a plan view of the cover of the slot drain of figures 1 to 5;

Figure 14a shows a plan view of the mould of figures 5 to 7;

Figure 14b shows an isometric view of the mould of figures 5 to 7;

Figure 14c shows a side elevation of the mould of figures 5 to 7;

Figure 15a shows a cross section through a sleeve for joining a plurality of moulds of figures Mato 14c;

Figure 15b shows an isometric view of the sleeve of figure 15a;

Figure 15c shows a side elevation of the sleeve of figures 15a and 15b; and

Figure 15d shows a plan view of the sleeve of figures 15a to d.

Referring to the drawings, in particular figures 1 to 7, a drainage apparatus, in the form of a slot drain 1 is shown. The slot drain 1 is formed from a number of components assembled together.

The slot drain 1 comprises a pair of channel walls 2, arranged opposite one another so as to form a long channel therebetween. Each channel wall 2 in this embodiment is lm long and 185mm in height and formed (for example by injection moulding or extrusion) from a plastic or composite material. Each channel wall 2 is substantially planar, formed largely as a plate having a depth of about 6mm, but with various formations extending from the plate-like form. The channel walls 2 each have inside and outside surfaces, the inside surfaces opposing one another and being separated from one another by approximately 30mm in this embodiment. Thus, in the present embodiment, a channel between the channel walls 2 is defined with a width of approximately 30mm and a length of about 1000mm, but of course this can be varied.

On the inside surface of each channel wall 2 (see figure 9b) beading 3 extends along the length, near to the base of the channel wall 2; the beading 3 of this embodiment being set at about 60mm from the base of the channel wall 2 and having a depth of about 2mm.

The beading 3 serves as a means for aligning a plurality of resilient components, in the form of resilient pads 4, which are spaced along the length of the channel wall 2. In this embodiment, four resilient pads 4 are equally spaced along each inside surface of each channel wall, so as to oppose corresponding resilient pads 4 on the opposing wall. The resilient pads 4 bias the channel walls 2 away from each other, into an expanded condition of the slot drain 1. Each pad may for example be around 50mm long, 20mm high and 15mm in depth and may be formed of (or comprise) nitrile butadiene (or other synthetic rubbers).

The beading 3 can also serve to support a temporary pin (not shown) for holding the channel walls 2 apart, before the slot drain 1 is put into use.

Extending through the channel walls 2 beneath the level of the beading 3 and resilient pads 4 are a plurality of apertures 5. In this embodiment five apertures 5 of about 19mm diameter are provided, equally spaced along the length of the channel walls 2. The channel walls 2 are so-moulded that the apertures 5 meet spigots 6 extending outward from the outside surfaces of the walls. Each spigot 6 has a bore through it, so that the aperture 5 extends through to the end of the spigot 6. In the present, exemplary, embodiment, each spigot has a length of 22mm and an O/D of 21.5mm, so as to fit into pipe/tube with a corresponding I/D.

At the base of each channel wall 2, extending from its outer surface all the way along its length, a base flange 7 is formed, so as to provide a foot, enabling the slot drain 1, when placed on a horizontal flat surface to stand upright, such that the channel extends perpendicular to the surface. In this particular embodiment, each flange 7 extends approximately 50mm from the inside edge of the channel wall 2 and tapers from a thickness of 5mm adjacent the planar surface of the wall 2, to 3mm at its tip. Of course, as with all the measurements, those skilled in the art will be able to make suitable adaptations to the dimensions, in light of this description.

Above the spigots 6, and in this embodiment approximately 50mm from the base of each channel wall 2, a platform 8 extends from the outside surface, along the length of the channel wall 2. The platform 8 of this particular embodiment extends approximately 20mm from the outer surface of the channel wall. As with the flange 7, the platform in this embodiment tapers from a thickness of 5mm adjacent the planar surface of the wall 2, to 3mm at its tip. In contrast to the flange 7, which has its lower surface perpendicular to the wall 2, and the upper surface tapering towards the lower surface, the upper surface of the platform 8 is perpendicular with the wall 2, whilst its lower surface is angled upwards, to form the taper.

Finally, in terms of features of the channel walls 2, each channel wall 2 has on its outer surface a pair of longitudinal score lines 9, to act as cutting guides, such that the height of the channel walls 2 can be cut down, so as to provide a less deep slot drain (for a shallower concrete slab). The score lines 9 in this embodiment are arranged 50mm and 100mm from the top of the channel wall 2, but of course, as ever, in light of the present teaching, those skilled in the art may determine alternative dimensions.

Seated on top of each channel wall 2 is a head piece 10, which is shown in situ in figures 1 -8b and in isolation in figure 10b. Each head piece 10 is also manufactured from plastics/composite materials, for example by injection moulding or by extrusion. At the base of each head-piece, connection means is provided, to connect the head piece to a respective channel wall. The connection means consists of a groove 11 (vertical in normal use), into which the top end of the channel wall is inserted and attached, by snap fitting, adhesion or the like.

Each head piece 10 could be formed integrally with the channel wall 2. However, providing separate parts means that the height of the slot drain 1 can be adjusted by cutting down the height of the channel wall 2 before attaching the head piece 10 thereto.

Like the channel walls 2, the head pieces 10 are plate-like, being substantially planar, and having their primary plane in the vertical plane, in use. Each head piece 10 has an inner surface (visible in figure 10a) and an outer surface (visible in figure 10b), with the inner surfaces of the two head pieces 10 facing one another.

The main purpose of the head pieces 10 is to provide a support for a cover 12, which sits at the top of the slot drain and is provided with apertures/slits 13 to allow water to drain into the channel. The cover 12, shown in isolation in figure 13 is a unit which may normally be formed from metal (e.g. cast) or composite plastic according to the type of use, having slits arranged along its length, in the middle (so as to be above the channel in the slot-drain 1 in use) it is of the same length as the slot drain (lm in this embodiment), and in this embodiment has a width of 71mm and a depth of 9mm. the choice of size, number and arrangement of slits is a matter that can be adjusted by the skilled person as he/she sees fit, but in this particular embodiment, 49 slits 13 are provided, each having its long axis perpendicular to the length of the slot drain 1, each having a width of 10mm, a length of 21mm and being equally spaced along the length of the cover 12.

In consequence, at the top of each head piece 10, an outwardly extending extension is provided along the length of each head piece 10; in this embodiment each extension extends 19mm from the outer surface of the head piece 10 and each extension is provided with a longitudinal rebate 14, which together form a longitudinal recess in which the cover can sit. The longitudinal rebates in this example have a depth of 10mm and the cover 12 has a similar depth of 9mm. The rebates 14 extend along the entire length of the head pieces 10 and, in this embodiment have a width of 26mm. The cover 12 is loosely fastened to the head pieces 10 (in the recess provided by the rebates 14), so as to allow relative horizontal movement between the cover 12 and the head pieces 10, but restrain the cover 12 in the vertical (in use) direction. In one example, this is achieved by screwing screws (not shown) into holes 16 in the upper surface of the rebate 14, through specially shaped holes 17 in the cover. The holes 17 in the cover 12 may for example be cross-shaped, to allow lateral movement of the cover 12 relative to the screws.

The rebates 14 are sized to provide a recess that supports the cover 12, but has vertical edges 18 that are wider than the cover in the expanded state (of the slot drain) and edges that are closer together, optionally touching the edges of the cover, in the contracted state (of the slot drain). The rebates 14 in this embodiment are sized to support the cover 12 whilst expanding by at least 2.5mm on each side of the cover which accommodates typical levels of expansion, even in quite large slabs of concrete.

The images, in general, show the slot drain in the expanded condition, but figures 8a and 8b show exaggerated images of the contracted condition (in figure 8a) and the expanded condition (in figure 8b).

Apart from its main function supporting the cover 12, whilst allowing for relative movement of the channel walls 2 and the inside surfaces of the head pieces 10 towards and away from each other, the head piece 10 also supports a filter 19, arranged beneath the cover 12.

The filter 19 (shown in isolation in figure 12) is a broadly planar perforated device, with perforations smaller and more numerous than the slits 13 in the cover 12. The filter 19 can be formed simply from rigid plastic material and prevents the channel below the filter 19 from becoming over-silted. To allow easy removal (to clean off the detritus caught by the filter 19, it is provided with lifting eyes 20 on stalks 21, which in use extend upward, terminating just below the cover 12.

To support the filter 19, the inside surface of each head piece 10 is provided with an inwardly extending ledge 23. In the present embodiment each ledge 23 is arranged to extend 6mm inward, providing a total surface of 12mm to support the filter (6mm on each side). The relative dimensions (width) of the filter 19 and the cover 12 are such that (as shown in figure 8a) when the slot drain 1 is fully compressed, the vertical edges 18 of the rebates 14 abut the edges of the cover 12, and the inside surfaces of the head piece 10 abut the filter 19. Then, in the expanded condition (of figure 8b) the ledges 23 can still support the filter 19.

Below the ledges 23, further resilient components 24 of the same type as the resilient pads 4 are provided. Again, the resilient components 24 are spaced along the length of the inside surface of the head piece 10. In this embodiment, once again, four resilient components 24 are equally spaced and arranged so as to oppose corresponding resilient components 24 on the opposing inside head piece 10. The resilient components 24 bias the head pieces 10 and the channel walls 2 to which they are connected away from each other, into an expanded condition of the slot drain 1. Each resilient component 24 may again, for example, be around 50mm long and 20mm high.

However, each head piece 10 is thicker than the channel walls 2, having a thickness of 12mm, so as to be able to form the groove 11 capable of accommodating the 6mm thick channel walls 2, and have a thickness of 3mm each side thereof. In consequence, the inside surfaces of the head piece 10, which face each other, are closer than the opposing inside surfaces of the channel walls 2. Accordingly, to accommodate the extra 3mm in thickness, the resilient components 24 are each 12mm, rather than and 15mm in depth (when not compressed). Both the resilient components 24 on the head piece 10, and those attached to the channel walls 2 are each resiliently compressible by at least 2.5mm.

Several slot drains 1 may be arranged end-to-end next to one another to provide an appropriate length, equivalent to the length of the concrete slab (or slabs) for which they are providing the drainage and expansion function. However, those at each end, or at each end of the slot drain 1 if only one is used, have an end-plate 25. This is a simple plate, which is attached to the ends of the channel walls 2 and head pieces 10, for example by double sided neoprene tape or any other suitable means that allows for expansion and contraction of the slot drain 1.

Whilst the slot drain 1 could be used in the format discussed above, and water would drain directly out of apertures 5, it is preferred that the spigots 6 are connected (e.g. by solvent welding) to pipes 26, which extend beneath the concrete slab in use. These pipes 26 may be connected to collect and harvest the water entering the slot drain 1, or they may guide the water beneath the concrete for attenuated natural permeation. In particular, the pipes 26 may be perforated, in order to spread the area over which the water is discharged to produce a more sustainable system, providing drip-feed permeation into the sub-base.

It is contemplated that the slot drain 1 could be used with pre-formed concrete slabs, preferably specially formed pre-formed concrete slabs, having voids through which the pipes 26 can extend. However, it is preferred that the slot drain 1 is provided as a kit, together with one or more moulds (or “formers”) 27 into which concrete can be poured to form concrete slabs 28 in situ.

The moulds 27 are shown in isolation in figures 14a to 14c, and in combination with the slot drain 1 and concrete slab 28 in figures 5 to 7.

The moulds can be moulded (e.g. vacuum formed) from plastics or other materials that may also be bio-degradable and are provided with recesses 29 depending from a flat body 30. The recesses 29 are so arranged as to extend between apertures 5 in, and pipes 26 extending from the slot drain 1. Consequently, in this embodiment, the recesses 29 are arranged in a grid, each recess 29 spaced from its neighbour so as to provide a void therebetween, with the centres of adjacent voids arranged approximately 20mm apart (corresponding to the spacing between the centres of adjacent apertures 5. Each recess 29 is substantially square, with straight edges at the top (where it meets the body 30) and curved edges at the base. Each curved edge curves inward (i.e. to be closer to the centre of the recess in the middle, than at the corners. In this embodiment, the moulds 27 are 600mm x 600mm in area and formed from plastics material of 3mm thickness. The recesses 29 are 150mm x 150mm in area at the top, but at their minimum (where the curved sides are closest) at the bottom, they are just lOOxlOOmm. They have a depth of 50mm.

The recesses 29 are formed inboard of the periphery of the body 30, so as to leave a peripheral region 31 which can be joined to other moulds 27 using a rubber sleeve 32 of the type shown in figures 15a to 15d. This sleeve 32 is an essentially planar device, with long narrow openings 33 on each side, to accommodate the periphery of a mould 27. It is slid over the peripheral region of two adjacent moulds 27, to attach them to one another. The openings 33 are larger at the ends, to allow the peripheral regions 31 of the moulds 27 to easily slide in, before they are clamped between the lips 34 of the openings 33.

In use, the slot drains 1 are arranged along the edge of an area to be paved, after the usual preparation of the ground (e g. levelling and laying of an appropriate base course above the subgrade). A plurality of slot drains 1 may be connected together end-to end, each set on its flanges 7, so as to be perpendicular to the ground. End plates 25 are arranged at the outermost ends of the slot drains 1, and pipes 26 are connected to the spigots 6. These pipes 26 may be perforated, for drip-drainage, or may be connected to a water harvesting grid of pipes (not shown). Moulds 27 are then arranged, with their recesses 29 facing downwards, next to the slot drains 1.

The moulds 27 are set with a peripheral region 31 supported by the platform 8 of the slot drains, as shown in figures 5 and 6, preferably fixed thereto using doublesided tape, or other fixing means. As best seen in figure 7, the moulds 27 are arranged such that the pipes 26 extend along the voids between the recesses 29. Moulds 27 are connected to one another using the sleeves 32, so as to form a complete layer of the area required for formation of concrete slab 28. If, for example, a square area is prepared, slot drains 1 may be arranged all round the area where the slab 28 will be formed. In effect, forming a large, shallow open-topped cavity, the height of the slot drains 1 and the area of the moulds 27. A conventional mesh reinforcement 35 is then arranged on top of the moulds 27, spaced therefrom by spacers (not shown). Then, concrete is poured into the cavity up to or near to the height of the top of the head pieces lOand allowed to set. This creates concrete paving, having downwardly depending portions (in the recesses 29) with voids therebetween, into which surface water may run, via the slot drains 1. Expansion and contraction of the concrete will be allowed by the slot drains 1, which can contract and expand in response, owing to the resilient components between channel walls 2 and head pieces 10.

Slot drains 1 may, of course, be provided between two regions of concrete formed in this manner. Moreover, slot drains 1 may be prepared as set out above, but with pre-formed concrete slabs (having downwardly depending portions) spaced to fit between the pipes 26 put into place. Conceivably, conventional concrete slabs, without downwardly depending portions could be used, provided the base course was built up around the pipes 26 to the level of the platform 8, so that the slabs 28 do not bear on the pipes 26.

The above embodiment is described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.

Claims

1. A kit of parts comprising a slot drain for concrete slabs and a mould for moulding at least the base of a concrete slab; the slot drain being configured to expand and contract in response to contraction and expansion of one or more adjacent concrete slabs, the slot drain comprising a channel delimited by two opposing channel walls, the channel walls being resiliently biased apart, the slot drain being provided with a plurality of apertures provided in one or both channel walls for connection to a plurality of pipes; wherein the mould is provided with recesses to define downwardly depending portions of concrete; wherein the recesses are so arranged as to extend between apertures in, and/or pipes extending from, the slot drain.

2. A kit of parts according to claim 1 wherein the channel walls are resiliently biased apart by one or more resilient components arranged between the channel walls.

3. A kit of parts according to claim 1 or 2 further comprising a cover, having one or more apertures therein provided in a rebate.

4. A kit of parts according to claim 3 wherein the rebate is provided in head pieces attached to the channel walls and is sized to provide a recess that supports the cover, but has edges that are wider than the cover in the expanded state of the slot drain and edges that are closer together in the contracted state of the slot drain.

5. A kit of parts according to claim 3 or 4 wherein the rebate is sized to support the cover whilst expanding/contracting by at least 4mm.

6. A kit of parts according to claim 4 or 5 wherein the head pieces are each associated with respective channel walls and are provided with one or more resilient components arranged between them.

7. A kit of parts according to any of claims 4 to 6 wherein each head piece comprises a groove for connecting to a respective channel wall.

8. A kit of parts according to any of claims 3 to 7 comprising a filter underneath the cover, supported on ledges on opposing channel walls, or ledges extending from opposing surfaces of each head piece.

9. A kit of parts according to claim 8 wherein the filter is provided with one or more lifting eyes.

10. A kit of parts according to any preceding claim comprising an end plate at one or more ends of the channel, the or each end plate attached to one or both channel walls by a resilient connection or loosely fixed thereto.

11. A kit of parts according to any preceding claim further comprising a plurality of pipes attached thereto, such that water may drain out of the slot drain into the pipes.

12. A kit of parts according to claim 11 wherein the plurality of pipes are arranged at a base of the slot drain.

13. A kit of parts according to claim 11 or 12 wherein the plurality of pipes is spaced along the length of the slot drain.

14. A kit of parts according to claim 13 wherein the plurality of pipes is equally spaced along the length of the slot drain.

15. A kit of parts according to any of claims 12 to 14 wherein each pipe is perforated, such that water may drain out of the pipe directly beneath a concrete slab.

16. A kit of parts according to any preceding claim comprising a platform for engaging with a mould.

17. A kit of parts according to claim 16 when dependent on claim 12 or any claim dependent thereon wherein the platform is arranged towards the base of the slot drain, but above the apertures for the pipes.

18. A concrete slab provided with a kit of parts according to any preceding claim.

19. A concrete slab according to claim 18 provided with a kit of parts according to claim 11 or any claim dependent thereon, the concrete slab being provided with downwardly depending portions, between which pipes extend.

20. A kit of parts according to any of claims 1 to 17 wherein the recesses may be arranged in a grid each recess being substantially square and each substantially square recess having substantially straight edges at the top and curved edges at the base, the curved edges curving inward.

21. A kit of parts according to any of claims 1 to 17 and 20 wherein each recess is at least 40mm deep.

22. A kit of parts according to any of claims 1 to 17 and 20 or 21 further comprising sleeves to join a plurality of moulds.

23. A kit of parts according to any of claims 1 to 17 and 20 to 22 comprising a plurality of slot drains and a plurality of moulds for moulding at least the base of a concrete slab.

24. A method of forming concrete paving, comprising: providing the kit of parts according to any of claims 1 to 17 and 20 to 23, arranging the slot drain adjacent to one or more concrete slabs.

25. A method according to claim 24 comprising arranging the slot drain between concrete slabs.

26. A method according to claim 24 or 25 further comprising arranging the mould adjacent to the slot drain and pouring concrete into the mould comprising recesses to form a concrete slab.

27. A method according to any of claims 24 to 26 further comprising arranging a plurality of moulds adjacent to the slot drain, joining said moulds and pouring concrete into the mould to form concrete slab.

28. A method according to any of claims 24 to 27 further comprising pouring the concrete to create a slab having a depth of at least 150mm from the base of the mould, or at least 150mm from the top of the mould.