GB2605789A

GB2605789A - Apparatus and methods for installing paving

Info

Publication number: GB2605789A
Application number: GB2105175.0A
Authority: GB
Inventors: Alexander Oldham Jake
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-04-12
Filing date: 2021-04-12
Publication date: 2022-10-19
Also published as: GB202105175D0

Abstract

An interlockable base panel 100 for supporting a paving slab, the base panel comprising two opposed main surfaces 102, 104, comprising a slab bearing surface and a ground facing surface and one or more interlockable edges 108, 110 for enabling the base panel to be interlocked with other such base panels in use. Wherein the slab bearing surface comprises means 112 for locating a paving slab in a defined position on the slab bearing surface. Further disclosed is a method of installing paving, comprising the steps of preparing a ground surface, laying a plurality of interlockable base panels onto the ground surface, wherein the ground facing surface of each base panel faces the ground surface and wherein the base panels are interlocked with one another and providing or forming at least one paving slab on the slab bearing surface of each interlockable base panel, using the respective means for locating.

Description

APPARATUS AND METHODS FOR INSTALLING PAVING

The present invention relates to apparatus and methods for installing paving. Merely by way of example, possible applications include laying a patio, terrace, path or driveway, or a paved area in a municipal, commercial or educational setting. The present invention is particularly applicable, but by no means limited, for use with paving slabs formed partly or wholly of resin-bound aggregate.

Background

Conventionally, laying paving slabs to produce a robust paved surface in which the slabs are laid in an even and uniformly-spaced manner is a skilled task, that can be difficult and time consuming for inexperienced installers (such as do-it-yourself or "DIY" enthusiasts) to do well. Even for experienced or professional installers, it can at times be a challenging process.

For instance, conventionally, the preparation of a suitable surface on which to lay the slabs, that is both level and firm (i.e. that does not give way or subside over time), may require deep excavations to be prepared, and a relatively thick base of compacted hardcore or other foundation material to be laid. Irregularities in such a base can lead to unevenness in the final paved surface.

Moreover, it can be difficult to ensure that the slabs are laid such that they are uniformly spaced from one another and correctly aligned and positioned relative to each other. Typically, once an array of slabs has been laid, the gaps between slabs are then filled (i.e. grouted, pointed or jointed) by a substance such as a sand/cement mix, or some other jointing compound. If the slabs are not laid in a uniformly spaced manner, the resulting lines of filler/grout will be of irregular width, which is generally undesirable and usually considered unsatisfactory. Furthermore, if the slabs are not correctly aligned and positioned relative to each other, the resulting pattern of slabs will look irregular and visually unappealing.

In practice, the above issues can result in substandard paving and/or dissatisfied customers or property owners Consequently the paving may have to be taken up and relaid, which is wasteful in terms of materials, time and money, and potentially damaging to the installer's reputation Additional problems may be encountered with resin-bound paving slabs. Resin-bound paving slabs are formed of aggregate particles embedded in a resin such as polyurethane resin. Such paving slabs may be formed by mixing and bonding aggregate particles of various sizes (or of a predetermined size or size range) with a resin within a suitable mould. The aggregate may be stone, granite, marble, or any other suitable material.

Such resin-bound slabs suffer from a number of disadvantages, including that they can be fragile and brittle. Moreover, there is a desire for laid resin-bound surfaces to be sufficiently water permeable -for example, "SuDS" (Sustainable Drainage System) compliant. Whilst resin-bound aggregate is inherently water permeable (due to the presence of small gaps between the aggregate particles through which water can pass), to enable good drainage of the finished surface requires the resin-bound aggregate to be laid upon a sufficiently water permeable base. In practice, forming a sufficiently water permeable base upon which to lay the resin-bound aggregate can be problematic, especially if concrete is used to form the base, as concrete has a relatively low degree of water permeability.

There is therefore a desire to address at least some of the above problems.

Summary

According to a first aspect of the present invention there is provided an interlockable base panel for supporting a paving slab, the base panel comprising-two opposed main surfaces, comprising a slab bearing surface and a ground facing surface; and one or more interlockable edges for enabling the base panel to be interlocked with other such base panels in use; wherein the slab bearing surface comprises means for locating a paving slab in a defined position on the slab bearing surface.

The expression "defined position" as used herein should be interpreted to refer to a specific fixed position that the respective paving slab is constrained into adopting relative to the base panel itself By virtue of such means for locating a paving slab in a defined position, and the interlockable nature of the base panel, once a plurality of such base panels have been laid and interlocked with one another in a regular (repeating or periodic) manner, paving slabs laid on (or provided on) the base panels can easily achieve uniform spacing and correct alignment and position relative to each other.

In use, the interlocked base panels also readily provide a level and firm surface for the slabs laid thereon. The base panels may also reduce the groundworks required for the installation of paving, potentially removing the need for deep excavation and only requiring a minimal base. A further advantage is that mortar may not be required between the ground and the slabs.

Moreover, the slab bearing surface of the base panel advantageously provides support to the respective slab laid thereon, across the full extent of the slab. Consequently, a material that may otherwise be insufficiently strong for paving, or prone to breaking, may now be used to form paving slabs, laid on and supported by the present base panels. For example, a paving slab that would otherwise be too brittle and/or fragile, such as an unsupported resin-bound aggregate slab, may be sufficiently strengthened by placement on the slab bearing surface of the base panel to result in a reliable and robust paved surface.

According to certain embodiments, the means for locating a paving slab may comprise one or more slab retaining members protruding from the slab bearing surface. Such slab retaining members may be integrally formed with the slab bearing surface, or may be subsequently fitted to the slab bearing surface (either at the point of manufacture or during installation).

Alternatively, the means for locating a paving slab may comprise one or more fixture points to which respective slab retaining members may be fitted in use. Such fixture points may comprise one or more slots, holes or recesses for receiving the slab retaining members. Such slots, holes or recesses advantageously provide the installer with flexibility to position slab retaining members where required for laying a desired array or pattern of slabs. Moreover, in the event that such a slot, hole or recess is not used to receive a respective slab retaining member, the slab bearing surface in that position effectively remains flat, such that a paving slab can be laid over the slot, hole or recess without becoming unevenly supported.

In certain embodiments, the slab retaining members may comprise one or more upstanding corners and/or one or more upstanding edges. Upstanding corners are well suited to constraining the position of a rectangular or square paving slab. On the other hand, upstanding edges may advantageously be used to receive and retain wet/uncured slab material, enabling the base panel to function as a mould in which a slab may be formed in-situ.

Alternatively, or in addition, the means for locating a paving slab may comprise a slab-receiving recess in the slab bearing surface. Such a recess may enable less material to be used to form the base panel; may remove the need for additional upstanding corner or edge parts (although they may nevertheless be used as well); and may also enable the base panel to function as a mould in which a slab may be formed in-situ at the time of installation, or alternatively to enable a slab to be formed as part of the manufacturing process of the base panel.

The means for locating may be adapted to receive a pre-made slab in use.

Alternatively, the means for locating may form a mould for receiving wet/uncured (e.g. poured or shovelled) slab mix in use, to enable a slab to be formed in-situ at the time of installation, or alternatively to enable a slab to be formed as part of the manufacturing process of the base panel.

Preferably, the interlockable base panel further comprises one or more drainage holes for draining liquid from the slab engaging surface through to the ground facing surface. By virtue of the one or more drainage holes, water (e.g. rainwater) may flow through the interlockable base panel, and a sufficiently high degree of drainage may be achieved to avoid pooling and promote infiltration of water into the ground. Accordingly, the resulting paved surface may be Sustainable Drainage System ("SuDS") compliant.

The interlockable base panel may be formed of a polymer material, for example by injection moulding or blow moulding For example, the interlockable base panel may be formed of high-density polyethylene, although those skilled in the art will appreciate that other suitable materials may be used instead Optionally, one or both of the opposed main surfaces may comprise one or more frangible lines (i.e. lines of preferential weakness) by which the panel may be divided apart.

Advantageously, this enables the panel to be used as a single panel or as one or more separate smaller panels, to fit the region being paved. This feature may function synergistically with the provision of one or more slots, holes or recesses in the slab bearing surface for receiving slab retaining members, as the divided panels may then be equipped with respective slab retaining members as required.

The interlockable base panel may further comprise one or more strengthening struts oriented parallel to the main surfaces, thereby enhancing the rigidity and strength of the base panel and improving its resistance to bending or other deformation in use. The struts may be integrally formed with the rest of the base panel, or may be separate components (e.g. metal rods or bars) that are introduced into the base panel during manufacture.

Optionally, the or each interlockable edge may comprise one or more tabs and/or one or more complementary sockets, to enable such edges of adjacent base panels to be interlockably engaged with one another. For example, the tabs and sockets may be shaped and configured to essentially form dovetail joints when connected, although other shapes of interlockable tabs and sockets are also possible. Engagement of the tabs and sockets is preferably reversable, to enable the installer to remove a panel if necessary, e.g. if placed in an incorrect position by mistake. The or each socket may comprise a tab-retaining base, to constrain the depth to which a respective tab may travel in the socket, such that the panels align flush with one other (in a vertical sense) once connected together.

Optionally, the interlockable base panel may further comprise a paving slab. That is to say, the interlockable base panel may be supplied with a paving slab already in place on the slab bearing surface.

According to a second aspect of the present invention there is provided a base structure comprising a plurality of base panels according to the first aspect of the invention, interlocked (i.e. interconnected) with one another.

According to a third aspect of the present invention there is provided a paved surface comprising the base structure according to the second aspect of the invention, and paving thereon.

According to a fourth aspect of the present invention there is provided a kit comprising: one or more interlockable base panels according to the first aspect of the invention; and one or more paving slabs.

The kit may further comprise a plurality of slab retaining members (e.g. upstanding corners or upstanding edges) for fitting to the base panels, thereby giving the installer flexibility to configure the base panels as required Alternatively, slab retaining members may be supplied separately.

Optionally, the or each paving slab may comprise at least a surface layer formed of resin-bound aggregate Moreover, the or each paving slab may be entirely formed of resin-bound aggregate Other materials may be used instead for the paving slabs According to a fifth aspect of the present invention there is provided a paving slab comprising at least a surface layer formed of resin-bound aggregate, adapted for use with an interlocking base panel according to the first aspect of the invention. Optionally the paving slab may be entirely formed of resin-bound aggregate According to a sixth aspect of the present invention there is provided a method of forming a paving slab comprising pouring slab mix onto the slab bearing surface of an interlockable base panel according to the first aspect of the invention.

According to a seventh aspect of the present invention there is provided a method of installing paving comprising the steps of': a) preparing a ground surface, b) laying a plurality of interlockable base panels according to the first aspect of the invention onto the ground surface, wherein the ground facing surface of each base panel faces the ground surface, and wherein the base panels are interlocked with one another; and c) providing or forming at least one paving slab on the slab bearing surface of each interlockable base panel, using the respective means for locating.

Optionally, the step of preparing the ground surface may comprise compacting (and levelling if necessary) any of bare earth, gravel, sand, aggregate, hardcore, recycled concrete, slag, topsoil or ballast.

The step of providing or forming at least one paving slab on the slab bearing surface may comprise placing a pre-made solid paving slab onto the slab bearing surface. Alternatively this step may comprise introducing wet/uncured slab mix onto the slab bearing surface, if the slab is to be formed in-situ The step of providing or forming at least one paving slab may further comprise applying a suitable adhesive to the slab bearing surface and/or the solid paving slab, before placing the solid paving slab onto the slab bearing surface, or before introducing the slab mix onto the slab bearing surface. Such an adhesive may be PVA (polyvinyl acetate), for example, although other adhesives are also possible The method may further comprise filling spaces between the paving slabs with a filler. Such a filler may comprise, for example, any of grout, mortar, resin-bound aggregate, jointing compound, or concrete. Other fillers are also possible.

Brief Description of the Drawings

Embodiments of the disclosure will now be described, by way of example only, and with reference to the drawings in which: Figure 1 schematically illustrates an interlockable base panel having upstanding corners which serve as slab retaining members, and interlockable edges comprising complementary tabs and sockets; Figure 2 schematically illustrates an interlockable base panel having fixture points in the form of slots for receiving corner-shaped slab retaining members, and an optional frangible line;

S

Figure 3 schematically illustrates an interlockable base panel having upstanding edges which serve as slab retaining members; Figure 4 schematically illustrates an interlockable base panel having fixture points in the form of elongate slots for receiving slab retaining members, and an optional frangible line; Figure 5 schematically illustrates an interlockable base panel having a recess in the slab bearing surface for receiving a paving slab, Figure 6 schematically illustrates an interlockable base panel in which the interlockable panel includes a tab-retaining base; Figures 7a to 7c schematically illustrate paving slabs having a concrete support layer or substrate, and a surface formed of resin-bound aggregate, suitable for use with the present interlockable base panels; Figures 8a and 8b schematically illustrate an interlockable base panel having a paving slab in place; Figure 9 schematically illustrates an interlockable base panel incorporating a plurality of strengthening struts; Figure 10 schematically illustrates an alternative interlockable base panel having a different configuration of interlockable edges, with a paving slab in place; Figure 11 schematically illustrates an alternative interlockable base panel having a different configuration of interlockable edges, with a paving slab in place; Figure 12 schematically illustrates the installation of paving using interlockable base panels according to the present disclosure, onto which pre-made paving slabs are placed on site; Figure 13 schematically illustrates the installation of paving using interlockable base panels according to the present disclosure, onto which wet/uncured slab mix is introduced on site; and Figures 14a to 14c schematically illustrate a series of patterns in which interlockable base panels according to the present disclosure may be arranged.

In the figures, like elements are indicated by like reference numerals throughout.

Detailed Description

The embodiments disclosed herein represent the best ways known to the Applicant of putting the invention into practice However, they are not the only ways in which this can be achieved.

interlockable base panels Referring initially to the embodiment shown in Figure 1, there is provided an interlockable base panel 100 for supporting a paving slab (not shown in this figure). In use, an interconnected plurality of such panels 100, forming an overall base structure (400 in Figures 12 and 13), may be located underneath a paved surface made up of a plurality of paving slabs On a driveway or patio, for example), to improve the strength of the paved surface and to facilitate easy, level and uniform installation of the paving slabs.

The interlockable base panel 100 comprises two opposed main surfaces, namely a slab bearing surface 102 and a ground facing surface 103.

The slab bearing surface 102 may, as in the embodiment of Figure 1, comprise a substantially planar surface on which a paving slab may be located, formed and/or adhered.

The slab bearing surface 102 may also comprise a rough or roughened surface for improving the purchase of a paving slab on the slab bearing surface 102 and/or improving the performance of an intervening adhesive for adhering such a paving slab to the slab bearing surface 102. For example, such surface roughening of the slab bearing surface 102 may increase the contact surface area between the slab bearing surface 102 and the paving slab or intervening adhesive, and/or may enable keying of adhesive into the slab bearing surface 102.

The ground facing surface 103 is located on a side of the interlockable base panel 100 opposed to the slab bearing surface 102. In use, the ground facing surface 103 may be placed directly on the ground (not shown) or on one or more sublayers (e.g of compacted hardcore, not shown) laid on top of the ground, to provide further support, stability and/or drainage to the paved surface (not shown).

The interlockable base panel 100 may also comprise, as in the embodiment shown in Figure 1, one or more drainage holes 106 for draining liquid, such as rainwater, from the slab engaging surface 102 through to the ground facing surface 103 Rainwater falling on -1 0 -or flowing over the paved surface (not shown) may thereby be readily drained into the ground beneath the base panel 100 when installed By promoting infiltration of water into the ground, the resulting paved surface may be Sustainable Drainage System ("SuDS") compliant.

The interlockable base panel 100 of Figure 1 comprises four interlockable edges 104 which enable the panel 100 to be interlocked with other such panels when in use. Such other panels may be identical to the interlockable base panel 100 shown in Figure 1, or may be different sizes, and in use may be arranged adjacent to the interlockable base panel 100 of Figure 1. Such adjacent interlockable panels (not shown) may comprise corresponding interlockable edges to mutually engage one or more of the interlockable edges of the base panel 100 of Figure 1.

In the embodiments shown in Figures Ito 6, 8b, 9, 11, 12 and 13, each interlockable edge 104 comprises a series of tabs 108 and complementary sockets 110. It will be appreciated that the long interlockable edges 104 of each base panel are complementary to one another, and likewise the short interlockable edges 104 of each panel are complementary to one another, thereby enabling similar adjacent panels to be interlocked along the long edges and/or the short edges 104, by engaging the tabs 108 within the sockets 110.

Advantageously, the tabs 108 and sockets 110 may be shaped and configured to essentially form dovetail joints when connected, thereby preventing the tabs 108 from being pulled out of the sockets 110 sideways. However, other shapes of interlockable tabs and sockets are also possible. Preferably the tabs 108 and the sockets 110 (or other such interlockable features of the interlockable edges 104, some examples of which are described below) are integrally formed with the rest of the base panel 100.

By interlocking several interlockable panels 100 in the manner described above, an overall base structure (400 in Figures 12 and 13) having a strong, stable and planar surface may be quickly and readily installed, without requiring significant skill, and on which a paving surface may be laid.

The slab bearing surface 102 of the embodiment depicted in Figure 1 further comprises means for locating a paving slab in a defined position on the slab bearing surface In the particular embodiment shown in Figure 1, the means for locating a paving slab comprises four slab retaining members 112 protruding from the slab bearing surface 102 Such slab retaining members 112 may be integral to the slab bearing surface 102, or may be fitted separately.

In the embodiment shown in Figure 1, such slab retaining members 112 are provided in the form of four upstanding corners 112 which may serve to locate and retain a paving slab therebetween Such upstanding corners 112 may protrude from the slab bearing surface 102 to a height lower than the height of a paving slab located therebetween when in use. Consequently, the upstanding corners 112 may be hidden from view by subsequently introducing filler/grout between the slabs.

Such means for locating a paving slab serve to assist in accurately and readily installing paving slabs on the slab bearing surface 102 of the interlocking panel 100.

The interlockable base panel 100 shown in Figure 1 (and likewise the other embodiments and variants described below) may be formed of a polymer material, for example by injection moulding or blow moulding. In particular, the interlockable base panel 100 may be formed of high-density polyethylene (HDPE), which is also known as polyethylene high-density (PEHD). In particular, the interlockable base panel 100 may be formed of recycled HDPE.

Recycled HDPE is readily available and formed, and has structural properties suitable for the intended use of the interlockable base panel 100. Further, in use, the interlockable base panel 100 is generally not visible from the surface of the paving, and therefore any surface irregularities sometimes associated with recycled HDPE are immaterial.

In alternative embodiments, the means for locating a paving slab may comprise one or more fixture points to which respective slab retaining members may be fitted in use. For instance, referring now to Figure 2, an alternative embodiment is provided in which the fixture points comprise eight corner-shaped slots 113 for receiving corner-shaped slab retaining members 112' which, when fitted, resemble the upstanding corners 112 of the embodiment illustrated in Figure 1 The embodiment shown in Figure 2 further differs from that of Figure 1 in that eight fixture points (corner-shaped slots 113) are provided. This enables the interlockable base panel 100 to be used in a number of ways.

More particularly, the interlockable base panel 100 of Figure 2 may be used in a similar fashion to that of Figure 1 in that four corner-shaped slab retaining members 112' may be fitted into the four outermost corner-shaped slots 113 in use. Thus, a paving slab may be located onto the slab bearing surface 102 with the edges of the slab being close to the edges of the base panel 100 -i.e. with the slab occupying substantially all the surface area of the base panel 100.

Alternatively, any suitable number of corner-shaped slab retaining members 112' may be fitted into the corner-shaped slots 113 in a number of combinations such that one or more paving slabs (potentially of a variety of sizes) may be located on the slab bearing surface 102, potentially such that they traverse at least one edge of the base panel 100. That is to say, paving slab(s) may be laid such that they span across onto one or more adjacent base panel(s) in use, whilst still retained by the slab retaining members.

Alternatively, eight corner-shaped slab retaining members 112' may be fitted into all the illustrated corner-shaped slots 113 such that two smaller (substantially half size) paving slabs may be located on the slab bearing surface 102 of the base panel 100.

The slab bearing surface 102 of the interlockable base panel 100 illustrated in Figure 2 further comprises an optional frangible line 121 (i.e. a line of preferential weakness) by which the panel 100 may be divided (e.g. snapped or cut) apart. The frangible line 121 may extend fully or only partly through the thickness of the base panel 100. Such a frangible line 121 allows the base panel 100 to be split into two pieces, such that each part can be located separate from one another and can receive a smaller (substantially half size) paving slab, e.g. according to the geometry of the site to be paved and/or the pattern of slabs to be laid.

It will be appreciated that the feature of the frangible line 121 may function synergistically with the provision of the corner-shaped slots 113, as the divided panels may then be equipped with respective slab retaining members 112' as required.

Referring now to Figure 3, the illustrated embodiment of the interlockable base panel 100 provides an alternative type of slab retaining member 114 to those shown in Figures 1 and 2. More particularly, in the embodiment shown in Figure 3, the slab retaining members comprise four upstanding edges 114 Such upstanding edges 114 may provide means for locating not only a pre-made paving slab, but may also accommodate a paying slab introduced in the form of poured (i.e. wet/uncured) slab mix that is subsequently allowed to cure. Thereby, the upstanding edges 114 may form a mould for receiving poured slab mix.

Such upstanding edges 114 may be integral with the slab bearing surface 102, or may be fitted separately.

If used to retain a pre-made slab, such upstanding edges 114 may protrude from the slab bearing surface 102 to a height lower than the height of the slab. Consequently, the upstanding edges 114 may be hidden from view by subsequently introducing filler/grout between the slabs. On the other hand, if the upstanding edges 114 are to function as a mould for receiving poured slab mix, e.g. for casting a slab in-situ, then the upstanding edges 114 should be the height of the slab to be formed.

As noted above, in alternative embodiments, the means for locating a paving slab may comprise one or more fixture points to which respective slab retaining members may be fitted in use. For instance, referring now to Figure 4, an alternative embodiment to that of Figure 3 is provided in which the fixture points comprise eight elongate slots 115 for receiving elongate slab retaining members 114' which, when fitted, resemble the upstanding edges 114 of the embodiment illustrated in Figure 3.

In the embodiment shown in Figure 4, the eight elongate slots 115 are suitable for -14 -receiving four or eight elongate slab retaining members 114' (or any number that may sufficiently complete at least one quadrilateral shape) Thus, in use, the slab retaining members 114' may be arranged as desired, to define any of three quadrilateral regions on the slab bearing surface 102 -i.e. a single large region for receiving a large slab, or one or two smaller regions for receiving smaller (half size) slabs.

The embodiment shown in Figure 4 further differs from that of Figure 3 in that eight fixture points (elongate slots 115) are provided This enables the interlockable base panel 100 to be used in a number of ways.

More particularly, the interlockable base panel 100 of Figure 4 may be used in a similar fashion to that of Figure 3 in that four elongate slab retaining members 114' may be fitted into the outermost elongate slots 115 in use. Thus, a paving slab may be located onto the slab bearing surface 102 with the edges of the slab being close to the edges of the base panel 100-i.e with the slab occupying substantially all the surface area of the base panel Alternatively, any suitable number of elongate slab retaining members 114' may be fitted into the elongate slots 115 in a number of combinations such that one or more paving slabs (potentially of a variety of sizes) may be located on the slab bearing surface 102, potentially such that they traverse at least one edge of the base panel 100. That is to say, paving slab(s) may be laid such that they span across onto one or more adjacent base panel(s) in use, whilst still retained by the slab retaining members.

Alternatively, eight elongate slab retaining members 114' may be fitted into all the illustrated elongate slots 115 such that two smaller (substantially half size) paving slabs may be located on to the slab bearing surface 102 of the base panel 100.

The slab bearing surface 102 of the interlockable panel illustrated in Figure 4 further comprises an optional frangible line 121 by which the panel may be divided (e.g. snapped or cut) apart. The frangible line 121 may extend fully or partly through the thickness of the base panel 100. Such a frangible line 121 allows the interlockable panel 100 to be split into two pieces, such that each part can be located separate from one another and can -15 -receive a smaller (substantially half size) paving slab, e.g. according to the geometry of the site to be paved and/or the pattern of slabs to be laid.

It will be appreciated that the feature of the frangible line 121 may function synergistically with the provision of the elongate slots 115, as the divided panels may then be equipped with respective slab retaining members 114' as required.

Whilst the elongate slab retaining members 114' may be provided as individual disconnected members, i.e. one for each side of a quadrilateral, the elongate slab retaining members 114' may alternatively be provided pre-joined in a quadrilateral shape, for fitting as one into correspondingly-positioned slots 115.

Slab retaining members according to any of the embodiments described herein (e.g. integral or insertable upstanding corners 112/112', or integral or insertable elongate edges 114/114') may be formed of a metal such as aluminium, or a rigid polymer, in order to provide a solid and stable edge to the slabs therein. This may result in a neater finish to the overall paving, and better defined edges to any slabs cast in-situ.

In Figure 5 there is provided a variation of the base panel 100 of the preceding embodiments, in which the means for locating a paving slab comprises a recess 123 in the slab bearing surface 102 for receiving one or more paving slabs. Such a recess 123 may enable less material to be used to form the base panel, may remove the need for additional upstanding corner or edge parts (although they may nevertheless be used as well, to provide additional means for locating), and may also enable the base panel 100 to function as a mould in which a slab may be formed in-situ or at the time of manufacture Such slab-receiving recesses 123 may be formed in different sizes or shapes, to suit different sizes or shapes of paving slabs. More than one such recess 123 may be formed in the slab bearing surface 102. Furthermore, multiple overlapping or concentric recesses 123, of different sizes or shapes, may be formed in a single slab bearing surface 102, potentially extending to different depths within the slab bearing surface 102.

Figure 6 illustrates a variant which differs from the embodiment of Figure 1 in that each -16 -socket 110 comprises a tab-retaining base 116 which may assist the tabs 108 to locate into the sockets 110 such that the top surface of the tabs 108 lines up flat and flush with the slab bearing surface 102 to create a flat and flush top surface across all of the interlocked panels. In turn, this results in a flat overall base structure that is formed by the plurality of interlocked base panels.

The tab-retaining base 116 may span only the base of each socket 110, or alternatively may span across the entirety of the ground facing surface 103.

In use, the tab-retaining base 116 may assist in preventing the base panel 100 from sinking into the surface beneath the base panel 100 further than desired, which may be particularly advantageous during periods or locations of heavy use. The tab-retaining base 116 may also add strength to the base panel 100 and rigidity to the tabs 108.

Figures 7a, 7b and 7c illustrate paving slabs 200 suitable for use with the present interlockable base panels 100. The paving slabs 200 comprise a surface layer formed of resin-bound aggregate 202 and a supporting layer or substrate comprising concrete 204.

More particularly, Figure 7a illustrates a cross-section of a paving slab 200 in which the surface layer formed of resin-bound aggregate 202 covers only one surface of the supporting layer 204 Figure 7b illustrates a perspective view of the same.

Figure 7c illustrates a cross-section of a variant of the paving slab 200 in which the surface layer formed of resin-bound aggregate 202 envelops the supporting layer 204, leaving only one surface of the supporting layer 204 exposed In the embodiment shown in Figure 7c, the surface of the supporting layer 204 left exposed is the surface that would face an interlockable base panel 100 in use. By being enveloped by the resin-bound aggregate, the slab 200 of Figure 7c is particularly suited for applications in which one or more sides of the slab will remain visible once installed -such as on steps, or on the edge of a raised terrace or patio, for example.

The paving slabs 200 illustrated in Figures 7a to 7c, or other slabs comprising only resin-bound aggregate, may be adapted for use with any of the interlocking base panels 100 described above.

Figures 8a and 8b illustrate an interlockable base panel 100, in this case as shown in Figure 1, comprising a paving slab 200, e.g. as shown in Figures 7a and 7b, in place on the slab bearing surface 102 of the base panel 100.

The paving slab 200 may be adhered to the interlockable base panel 100 during manufacture, or the base panel 100 and the slab 200 may be manufactured integrally together (e.g. by casting the slab 200 on the base panel 100), thereby forming what is in effect an interlockable paving slab 300. Thus, an interlockable base panel 100 already comprising a paving slab 200 may be supplied and installed as a single entity.

As can be seen from Figure 8b, the paving slab 200 may protrude from the slab bearing surface to a greater height than the means for locating (e.g. upstanding corners 112).

Figure 9 illustrates an embodiment in which the interlockable base panel 100 further comprises one or more strengthening struts 118 oriented parallel to the main surfaces. In the embodiment shown in Figure 9, the strengthening struts 118 are arranged in a grid pattern, the plane of which is parallel with the main surfaces of the base panel 100 In the embodiment shown in Figure 9 the strengthening struts 118 are located on or in the slab bearing surface 102. However, such strengthening struts 118 may be located on or in the ground facing surface 103, and/or they may be located inside the base panel 100 between the ground facing surface 103 and the slab bearing surface 102.

Preferably the strengthening struts 118 are integrally formed with the rest of the base panel 100, including the slab bearing surface 102, the ground facing surface 103, and the interlockable features (e.g. tabs 108 and complementary sockets 110) of the interlockable edges 104. In particular, the entire base panel 100, including the strengthening struts 118, made be formed in a unitary manner from a polymer material, for example by injection moulding, blow moulding or a similar technique, thereby eliminating additional steps in the manufacturing process and reducing the overall production costs.

Figure 10 illustrates an alternative interlockable base panel 100 (shown with a paving slab 200 in place), in which the interlockable edges 104, 104' of the base panel 100 comprise one or more teeth 104b and one or more complementary apertures 104a.

More particularly, in the embodiment illustrated in Figure 10, the interlockable edges 104 comprise a series of apertures 104a facing upwards, whereas the interlockable edges 104' comprise a series of complementary teeth 104b facing downwards. The apertures 104a and teeth 104b are arranged such that, when an interlockable edge 104' comprising teeth 104b is laid on top of an interlockable edge 104 comprising apertures 104a, the interlockable edges 104, 104' interlock, by the teeth 104b engaging within the apertures 104a. As illustrated, the interlockable edges 104 preferably extend outward, perpendicular to the side of the base panel 100, to permit the interlockable edges 104' to be brought down upon them.

Further, in the embodiment illustrated in Figure 10, the interlockable edges 104' comprising one or more teeth 104b may simultaneously serve as upstanding edges for locating a paving slab 200 As illustrated, the upstanding edges provided by the interlockable edges 104' may extend the entire thickness of the slab 200. Consequently, the top surface of each of the upstanding edges 104' may remain visible in the finished paving, separating the slabs 200 instead of lines of grout or filler.

Referring now to Figure 11, in an alternative embodiment of an interlockable base panel 100 the interlockable edges 104 comprise one or more sideways-extending tabs 104b (effectively in the form of tenons) and/or one or more complementary sockets 104a (effectively in the form of mortises) Two interlockable panels 100 according to the embodiment shown in Figure 11 may be interlocked by sliding an interlockable edge comprising one or more tabs/tenons 104b up against an interlockable edge comprising one or more sockets/mortices 104a, engaging the tabs/tenons 104b within the sockets/mortises 104a. By virtue of the sideways engagement of the tabs 104b and sockets 104a, effectively in the manner of mortise-and-tenon joints, adjacent panels 100 may be connected in such a manner that the slabs 200 thereon have minimal gaps between them, such that filling or grouting of the gaps may not be necessary.

Methods of installation Figure 12 illustrates an array of paving slabs 200 being installed onto a three-by-three arrangement of interlocked base panels 100, each according to the embodiment illustrated in Figure 1 (i.e. having upstanding corners 112 as slab retaining members).

More particularly, after preparing the ground surface (for example by compacting bare earth using e.g. a vibrating plate), a plurality of interlockable panels 100 may be laid sideby-side on the compacted earth and interlockably engaged with one another. As shown in Figure 12, the interlockable panels 100 may be arranged in a grid type arrangement, thereby forming a base structure 400 (comprising the plurality of interlocked panels 100) on which the slabs 200 may be laid. In the illustrated example, the base structure 400 comprises nine interlocked panels 100 arranged in a three-by-three arrangement, with their respective ground facing surfaces 103 facing towards the compacted earth.

The installer 410 may then proceed to locate a respective paving slab 200 onto the slab bearing surface 102 of each of the nine interlocked base panels 100. The slabs 200 may be laid once all the base panels have been interlocked, or each slab 200 may be laid immediately following the placement of its respective base panel 100. As shown in Figure 12, the installer 410 is assisted in accurately locating the paving slabs 200 by the upstanding corners 112 of the slab bearing surfaces 102. Adhesive (e.g. PVA) may be applied between each paving slab 200 and its respective base panel 100, to securely hold the slabs 200 in place.

To complete the paving, the spaces between the paving slabs 200 may then be filled with a filler. The filler may for example comprise any of grout, mortar, resin-bound aggregate, jointing compound, or concrete.

Figure 13 illustrates an array of paving slabs 200 being installed onto a three-by-three arrangement of interlocked base panels 100, each according to the embodiment illustrated in Figure 3 (i.e. having upstanding edges 114 as slab retaining members). The installation method illustrated in this Figure corresponds to that of Figure 12 in terms of the preparation of the ground and the formation of the base structure 400 comprising a plurality of interlocked panels 100.

-20 -However, the installation method illustrated in this Figure differs from that of Figure 12 in that, rather than laying pre-made slabs, the installer 410 introduces (e.g. pours or shovels) paving slab mix 206 onto the slab bearing surface 102 of each of the nine interlocked panels 100. The user is assisted in doing this by the upstanding edges 114 of the slab bearing surfaces 102 effectively forming moulds to retain the slab mix 206 until it cures to form solid paving slabs 200.

The paving slab mix may comprise aggregate mixed within a liquid resin, such that resulting paving slabs 200 comprise cured resin-bound aggregate. Alternatively, the paving slab mix may comprise concrete, tarmac, or any other suitable material.

In variants of the above methods, the step of preparing the ground surface may comprise compacting any of: gravel, sand, aggregate, hardcore, recycled concrete, slag, topsoil or ballast, prior to laying the interlocking base panels 100.

Figures Na to 14c schematically illustrate, by way of example only, plan views of three different patterns in which interlocked base panels 100 according to embodiments of the present disclosure may be arranged. More particularly, Figure 14a illustrates a "stack bond" grid type arrangement, Figure 14b illustrates an offset "running bond" arrangement, and Figure 14c illustrates a herringbone arrangement. Advantageously, the slabs 200 that are laid upon these base panels 100 may adopt a corresponding pattern, but this need not necessarily be the case (since slabs may be smaller than the base panels on which they are laid, and/or slabs may span across adjacent base panels). Kits

The elements of any of the embodiments described herein may be provided as kits, to facilitate implementation of the present invention Thus, such a kit may comprise one or more interlockable base panels 100 according to any of the embodiments described herein, and one or more paving slabs 200 as described herein.

Such a kit may further comprise a plurality of slab retaining members 112/114' for fitting to the interlockable base panel(s) 100 Optionally such a kit may comprise multiple sizes of paving slabs 200 and interlockable base panels 100.

Modifications and alternatives Detailed embodiments and some possible alternatives have been described above. As those skilled in the art will appreciate, a number of modifications and further alternatives can be made to the above embodiments whilst still benefiting from the inventions embodied therein.

It will be appreciated that the expressions "slab bearing surface" and ground facing surface", as used herein with respect to the two opposed main surfaces 102 and 103, relate to the base panel 100 as in use. Variants of certain embodiments (for example those of Figures 2, 4 and 5) may be envisaged in which the features of the slab bearing surface 102 (e.g. slots 113 or 115, or recess 123) are also present on the opposing surface 103 of the panel 100, either in the same configuration as on the surface 102 or in a different configuration, thus enabling such base panels to be used either way up.

Furthermore, combinations of corner-shaped slots 113 and/or elongate slots 115 and/or slab-receiving recesses 123 may be incorporated within the surface 102, and likewise within the opposing surface 103, to give the installer greater flexibility as to whether (and where) to use corner-shaped slab retaining members 112' or elongate slab retaining members 114' (or a combination of the two), or to make use of the slab-receiving recesses 123, as appropriate for the installation in question For example, one variant of the base panel may have a plurality of corner-shaped slots 113 on the surface 102, and a plurality of elongate slots 115 on the surface 103, such that the panel may be used either way up, depending on whether corner-shaped slab retaining members 112' or elongate slab retaining members 114' are to be fitted. Similarly, a second variant may have a plurality of corner-shaped slots 113 on the surface 102, and one or more slab-receiving recesses 123 on the surface 103. A third variant may have a plurality -22 -of elongate slots 115 on the surface 102, and one or more slab-receiving recesses 123 on the surface 103. A fourth variant may have a combination of corner-shaped slots 113 and elongate slots 115 on the surface 102, and one or more slab-receiving recesses 123 on the surface 103. Other combinations of corner-shaped slots 113 and/or elongate slots 115 and/or slab-receiving recesses 123 are possible in either surface 102 or surface 103.

The various base panels 100 disclosed herein may be made of solid material, or may comprise one or more cavities (e.g. in a grid formation) on the ground facing surface 103, which may reduce the weight and reduce material use of the base panel 100, and may also help to maximise water flow.

Optionally, during installation, one or more ground anchors (e.g. elongate metal spikes) may be used to secure a base panel 100 to the ground, to prevent sideways movement of the base panel 100 during the installation process (and subsequently), and thereby enhance the stability of the overall base structure 400 that is formed, and the stability of the resulting paving. A ground anchor may for example be inserted through a drainage hole 106. Alternatively, dedicated holes may be provided in the base panels 100 for receiving such ground anchors.

As illustrated in Figures 7a-7c, the paving slabs 200 for use with the present interlocking base panels 100 may have a concrete support layer or substrate, and a surface formed of resin-bound aggregate However, the paving slabs 200 may alternatively be formed of any other suitable material In particular, the paving slabs 200 may be entirely formed of resin-bound aggregate, with strength being afforded to such slabs by the underlying slab bearing surface 102 of the base panels 100 If resin-bound aggregate slabs are to be cast in-situ on the interlockable base panels 100, the drainage holes 106 should be a maximum of 3mm in diameter, to prevent the resin-bound aggregate from passing through the holes. However, if pre-made slabs 200 are to be used (e.g. made of Indian sandstone, concrete, porcelain, or any other suitable material), the drainage holes 106 may be larger.

The aggregate size within the resin-bound aggregate may vary from lmm in diameter up to -23 -lOmm in diameter and may depend on the style and/or purpose of the paving. For example, a paving slab may have aggregate of 1 mm to 5mm in diameter for a tighter finish. A paving slab for use in a driveway may have aggregate ranging from lmm up to lOmm in diameter for a stronger paving.

Grouting the paving after the installation of the paving slabs 200 onto the base panels 100 may be done with the same material as the surface layer of the paving slabs 200, such as with resin-bound aggregate. Accordingly, a matching surface may be achieved, to give a uniform overall appearance to the paved surface. Alternatively, a different colour of resin-bound aggregate may be used for the grouting, to give the grout lines a contrasting appearance.

Paving slabs 200 of different sizes may be used with corresponding differently-sized interlockable base panels 100 However, the paving slabs may or may not match the size of the interlockable panels.

The paving slabs 200 and the interlockable base panels 100 may be any desired shape and size. For example, the paving slabs may measure 300mm by 300mm, or 600mm by 300mm, or 600mm by 600mm, or 600mm by 900mm, or any other appropriate size. When supplied in kit form, a kit may comprise, for example, four or five differently-sized slabs 200, with four or five corresponding differently-sized interlockable base panels 100, for use in forming various patterns.

If desired, an anti-slip surface may be applied to the paving slabs during manufacture and/or during installation, to provide additional slip resistance

Claims

-24 -CLAIMSAn interlockable base panel for supporting a paving slab, the base panel comprising: two opposed main surfaces, comprising a slab bearing surface and a ground facing surface; and one or more interlockable edges for enabling the base panel to be interlocked with other such base panels in use; wherein the slab bearing surface comprises means for locating a paving slab in a defined position on the slab bearing surface.
2. An interlockable base panel according to claim 1, wherein the means for locating a paving slab comprises one or more slab retaining members protruding from the slab bearing surface.
3. An interlockable base panel according to claim I, wherein the means for locating a paving slab comprises one or more fixture points to which respective slab retaining members may be fitted in use.
4 An interlockable base panel according to claim 3, wherein the one or more fixture points comprises one or more slots, holes or recesses for receiving the slab retaining members.
5. An interlockable base panel according to any of claims 2 to 4, wherein the slab retaining members comprise one or more upstanding corners
6. An interlockable base panel according to any of claims 2 to 5, wherein the slab retaining members comprise one or more upstanding edges.
7. An interlockable base panel according to any preceding claim, wherein the means for locating a paving slab comprises a slab-receiving recess in the slab bearing surface. -25 -
8. An interlockable base panel according to any preceding claim, wherein the means for locating is adapted to receive a pre-made slab in use
9. An interlockable base panel according to any of claims 1 to 7, wherein the means for locating form a mould for receiving wet/uncured slab mix in use
10. An interlockable base panel according to any preceding claim, further comprising one or more drainage holes for draining liquid from the slab engaging surface through to the ground facing surface.
11. An interlockable base panel according to any preceding claim, being formed of a polymer material.
12. An interlockable base panel according to claim 11, being formed of high-density polyethylene.
13. An interlockable base panel according to any preceding claim, wherein one or both of the opposed main surfaces comprise one or more frangible lines by which the panel may be divided apart.
14. An interlockable base panel according to any preceding claim, further comprising one or more strengthening struts oriented parallel to the main surfaces.
15. An interlockable base panel according to any preceding claim, wherein the or each interlockable edge comprises one or more tabs and/or one or more complementary sockets
16. An interlockable base panel according to claim 15, wherein the or each socket comprises a tab-retaining base.
17. An interlockable base panel according to any preceding claim, further comprising a paying slab.-26 -
18. A base structure comprising a plurality of the interlockable base panels according to any preceding claim, interlocked with one another.
19. A paved surface comprising the base structure according to claim 18, and paving 5 thereon.
20. A kit comprising: one or more interlockable base panels according to any of claims 1 to 16; and one or more paying slabs.
21. A kit according to claim 20 when dependent on any of claims 3 to 6, further comprising a plurality of slab retaining members for fitting to the base panels.
22 An interlockable base panel according to claim 17, or a kit according to claim 20 or claim 21, wherein the or each paving slab comprises at least a surface layer formed of resin-bound aggregate.
23. An interlockable base panel according to claim 17, or a kit according to claim 20 or claim 21, wherein the or each paving slab is entirely formed of resin-bound aggregate
24. A paying slab comprising a surface layer formed of resin-bound aggregate, adapted for use with an interlocking base panel according to any of claims 1 to 16; optionally wherein the paying slab is entirely formed of resin-bound aggregate.
25 A method of forming a paying slab comprising pouring slab mix onto the slab bearing surface of an interlockable panel according to any of claims 1 to 16.
26. A method of installing paying comprising the steps of: a) preparing a ground surface; b) laying a plurality of interlockable base panels according to any of claims 1 to 17 or claim 22 or claim 23 onto the ground surface, wherein the ground facing surface of each base panel faces the ground surface, and wherein the base panels are interlocked with one another; and -27 -c) providing or forming at least one paving slab on the slab bearing surface of each interlockable base panel, using the respective means for locating
27. A method according to claim 26, wherein the step of preparing the ground surface comprises compacting any of: bare earth, gravel, sand, aggregate, hardcore, recycled concrete, slag, topsoil or ballast.
28. A method according to claim 26 or claim 27, wherein the step of providing or forming at least one paving slab on the slab bearing surface comprises placing a solid paving slab onto the slab bearing surface, or introducing wet/uncured slab mix onto the slab bearing surface.
29. A method according to claim 28, wherein the solid paving slab comprises a surface layer formed of resin-bound aggregate, or is entirely formed of resin-bound aggregate; or wherein the paving slab mix comprises aggregate mixed within a liquid resin.
30. A method according to claim 28 or claim 29, wherein the step of providing or forming at least one paving slab further comprises applying a suitable adhesive to the slab bearing surface and/or the solid paving slab, before placing the solid paving slab onto the slab bearing surface, or before introducing the slab mix onto the slab bearing surface.
31. A method according to any of claims 26 to 30, further comprising filling spaces between the paving slabs with a filler.
32. A method according to claim 31, wherein the filler comprises any of: grout, mortar, resin-bound aggregate, jointing compound, or concrete.