GB2428432A

GB2428432A - Surface covering panels

Info

Publication number: GB2428432A
Application number: GB0514957A
Authority: GB
Inventors: Fergus Johnathan Ardern
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-07-21
Filing date: 2005-07-21
Publication date: 2007-01-31
Anticipated expiration: 2025-07-21
Also published as: WO2007010195A1; GB0514957D0; GB2428432B

Abstract

A surface covering panel for use in ground covering or decking or for other cladding or panelling has a complex shape in plan which allows the panel to be joined to a number of like panels to form a continuous array. The panel has a rectangular central section 13 and a pair of end sections 14, 15 extending from opposed end edges of the central section 13. Each end section has an isosceles trapezium 16, 17 part adjoining the central section 13 and a rectangular part 18, 19 adjoining the trapezium part 16, 17. The external edges of the panel are configured to allow interengagement with corresponding edges of like panels by means of a projecting section and a recessed section which comprise raised and lowered interlocking portions.

Description

SURFACE COVERING PANELS

Field of the Invention

The present invention relates to surface covering panels and in particular to such a panel that may be built into a planar array, wherein the individual panels are interconnected by a locking mechanism

Review of the Prior Art known to the Applicant

Examples of panels which interconnect at their edges to form a planar array may be found in the following patents, US3,500,606, US4,373,306 and in PCT application In the case of the present inventors earlier patent applications W097/18353 and W005035874, constructional panels are described wherein individual panels are connected together by interconnecting means which form at least some of the edges of the panels. The interconnecting of panels in this way, enables a planar array of panels to be built up, the array being suitable for use as temporary decking on soft ground, hard standing for aircraft, a temporary track way over ground, a temporary runway for aircraft, amongst other possible uses. By the use of appropriately sized panels, the array may he used to cover areas which are smaller in size, such as kitchens, bathrooms, tent floors and the like.

The later of these two disclosures, W005035874, discloses a constructional panel of a particularly beneficial shape, such that when panels of this shape are used to build an array of such panels and wherein the panels are interconnected at their adjacent edges, there are 110 linear lines of weakness extending across the array in any direction. The particular shape of panels disclosed therein is also described in detail herein.

The Panel disclosed in W005035874 is provided with a tongue and groove engagement/lock ing mechanism incorporated into some of the edges of the panel. There are problems associated with the use of such tongue and groove mechanisms as the fit between the tongue and groove must be tight in order to lock the panels together. As a result of this the panels may be difficult to fit together, the force required to abut the panels can result in damage to the tongue and groove mechanism. Additionally small bits of debris such as grit can make the fitting of panels together more difficult and/or result in small gaps between the upper surfaces of adjacent panels. Additionally, a manually engaged lock mechanism may be provided which enables the panels to be further locked to each other.

It is therefore a principal aim of the present invention to provide a surface covering panel suitable for building an array of like panels, wherein the panels are interconnected at their adjacent edges with no linear lines of weakness extending across the array, in any direction and to further provide a secondary locking mechanism which automatically locks tiles together when they are interconnected without the inherent problem of the tiles being difficult to fit together.

Summary of the Invention

According to tile present invention there is provided a surface covering panel conlprisillg a central section and two opposed end sections, the central sect ion being of generally rectangular forni with two parallel external side edges and two parallel end edges, each end section having all isosceles trapezium part conjoined to a rectangular part, the trapezium part having parallel long and short edges and a pair of external oblique edges, and the rectangular part having a pair of parallel first edges and a pair of external second edges, the short edge of the trapezium part conjoining an end edge of the central section and the long edge conjoining a first edge of the rectangular part, the other first edge of the rectangular part being external, and the length of the external side edges of the central part being substantially twice the length of either second edge of the rectangular parts, whereby a panel may be fitted together with other like panels in an array by engaging an oblique edge of an end section of one panel with an oblique edge of an end section of a second panel, a second edge of the rectangular part of the engaged end sections of each of the two panels engaging the respective side edge of the central section of the other panel, and a third panel is engaged with said two panels in a similar manner so that an end section thereof engages an end section of the one panel and the external first edge of said end section of the third panel engages the corresponding external first edges of the second panel, at least some of the external edges of the panel are configured for interengaging Connection to the corresponding edges of a second like panel by means of the external edges of the panel which further comprise a projecting section and a recessed section characterised in that said projecting section and recessed section have interlocking raised portion(s) and lowered portion(s), such that in use, when the projecting sections and recessed sections of two panels are engaged, the raised portion(s) interlock(s) with a corresponding lowered portion(s) on an adjacent panel to lock the panels together. The provision of the interlocking raised and lowered portions on the projecting and recessed sections gives a locking mechanism which locks interengaged panels together, the locking mechanism being autoniatically activated when the projecting and recessed sections of adjacent panels are interengaged with each other and giving rise to an array which is more rigidly locked together than an array which relies only on the interaction of simple projecting and recessed sections. There is thereibre no manual activation of the locking mechanism required and additionally the entire projecting and recessed region (tongue and groove equivalents) do not have to fit tightly to lock the panels together.

Preferably, the lowered portion comprises a groove. The manufacture of the lowered portion in the shape of a groove together with an appropriately shaped interlocking raised portion has been found to be particularly beneficial. The use of the groove shape allowing adjacent tiles to be slid together with the panels in essentially the same planar orientation.

Preferably the projecting section and recessed section each constitute approximately half of the engageable external edges of the panel. The use of projecting sections and recessed sections which each constitute approximately half of the engageable external edges of the panel when interengaged to form an array gives rise to an array wherein there are no gaps between adjacent panels through which water or water vapour readily pass.

Preferably the raised portion and the corresponding grooved portion are incorporated along the length of the projection section and corresponding recessed section as a single groove and correspondingly shaped raised portion. This combination of a projecting section and a recessed section, each of which constitute approximately half of the engageable external edges of the panel, which further comprises an interlocking grooved portion and correspondingly shaped raised portion, gives an array of panels which when engaged/locked together form a flooring arrangement that is substantially resistant to the passage of water or moisture between the engaged/locked panels.

Preferably the panel is made from a resiliently deformable material such as plastic material. The use of resiliently deformable materials such as plastic provides a panel which may be used on uneven ground and wherein, in use, when pressure is applied to the panel, the panel(s) can flex and thus contact the ground below the array at the point where the pressure is being applied rather than the panel dis-engaging from other adjacent panels.

Preferably the panel further comprises elevated areas on an upper planar surface and corresponding recessed sections on a lower planar surface, the recessed section being of larger cross-section in the plane of the surface than the corresponding elevated area. The position of elevated areas on the upper planar surface of the panel and recessed sections on the lower planar surface in this way give rise to a panel wherein some of the pressure applied by a user walking on the panel is dissipated by depression of the elevated areas on the upper plane in the direction of the corresponding recessed section.

Preferably the panel further comprises elongate indentations on a planar surface of the panel to facilitate the cutting of the panel into smaller sections. The provision of such depressions facilitates the cutting of sections off the panels such that the edge of the array that abuts walls and the like comprise a straight edge.

Preferably the shape of the raised portion(s) and lowered portion(s) enables the panels to be releasably engageable.

The use of an interlocking raised portion which has a semi-circular shaped cross-section and a correspondingly shaped lowered portion is particularly preferred for this purpose.

The semi-circular shape assisting the unlocking of the two portions. Additionally, if the lowered portion is an elongate groove that runs the majority of the length of the interengaging section, this provides a weakened point about which the panel will defbrm/bend during the disassembly of an array of panels, thus facilitating the disassembly.

Preferably the projecting section and the recessed Section further comprise a bevelled zone and a correspondingly shaped slot which abut each other when the panels are in use.

The provision of such a bevelled zone and correspondingly shaped slot on the projecting section and recessed section respectively aid the insertion of the projecting section into the recessed section during the assembly of an array of panels.

Preferably the projecting section further comprises a chamfer along the length of at least one of the joints where the external edge of the panel meets the projecting section. Such chamfered edges provides a pivot 1oint which further facilitates the disassembly of an array of panels.

According to a second broad aspect of the invention there is provided a method of building tip a substantially planar array of a Plurality of individual panels using panels according to any one of the previous panels wherein the second edge of one end sectioii of a first panel is brought into engagement with one side of the central section of a second panel, a second edge of an end section of the second panel simultaneously coming into engagement with a corresponding side edge of the central section of the first panel, said projecting section locating in the respective recessed section of the first and second panels, the two panels are moved relatively to bring the adjacent oblique edges of the respective end sections into engagement and the respective raised portion and grooved portion interlock to lock together the first and second panels, the external first edge of an end section of a third panel is brought into engagement with the first edge of the end section of the second panel already engaged with the first panel, the engaged lirst edges of the second and third panels are slid relatively to bring the second edge of the end section of the third panel into engagenlejit with the side edge of the central section of the first panel already engaged by the second panel, said projecting section locating in the respective recessed section of the first and third panels, and the respective raised portion and grooved portion interlocking to lock together the first and third panels thereafter to restrain relative separating movement between all three panels.

Preferably the projecting section and the recessed section each comprise approximately half of the engageable external edge of the panel and an appropriate waterproof sealant is used to seal points where adjacent tiles meet at the periphery of the array. The use of waterproof' sealant in this way prevents water tracking from the periphery of the array along the joints between adjacent panels into a centre of the array.

In this specification, the term surface covering panel' is used to refer to a generally planar panel the thickness of which is much smaller than the dimensions of the panel in its plane, and which may be used in the construction of one or more of a decorative, cladding, load-bearing or structural arrays of such panels. For example, the panel may be used with other like panels in constructing a temporary, semi-permanent or even essentially permanent area of flooring, ground_decking or hard-standing, or a pathway or track. The panel may instead he used in constructing cladding or panelling for a frame- work to form a space divider, screen or wall. The invention is not to be regarded as limited to these various uses, and may be used in many circumstances where an array of interconnected individual panels fulfils a demand. The panel may also be used on top of conventional wooden floors or concrete floors to provide an essentially waterproof flooring.

The surface covering panel of this invention has an overall external shape which is not a simple rectangle. Rather, the shape is somewhat complex but configured such that any one panel may he interconnected with a plurality of like panels, with no simple rectangular grid layout of lines of weakness between the interconnected panels. As such, the interconnected panels may form a particularly rigid array, allowing the panels to be used successfully to provide, for example, level grounddecki iig despite some unevenness in the ground on which the decking is laid. Alternatively, the panel may be flexible, depending upon the intended use.

The complex shape (in plan) of the panel of this invention includes an isosceles trapezium. Such a shape has two parallel sides of unequal length, and two further sides lying at the same angle (but in opposite senses) to each of those two parallel sides. In Anierican_Engljsh, such a geometric figure is normally referred to as an isosceles trapezoid, though the usual British-English term isosceles trapezium is used herein.

rief Description of the Drawings

Figure 1 is a schematic perspective view of an upper face of a panel according to the present invention.

Figure 2 is a schematic perspective view of a lower surfiice of a panel according to the present invention Figure 3 is an expanded view of a corner of a projecting section which fbrms part of the external edge of the panel in the direction of arrow A on figure I. Figure 4 is an expanded view of a corner showing a projecting section and an adjacent recessed section in profile in the direction of arrow B in figure 1.

Figure 5 shows three panels, each as shown in figure 1, being interlocked.

Figure 6 is a schematic perspective view of a metal insert designed to be embedded in a panel of the type shown in figure 1.

Figure 7 is a schematic view of a non-releasable locking mechanism for use with the present invent ion iscription of the Preferred Embodiment Referring initially to figure 1, there is shown a ground decking panel 10 manufactured principally from a plastics material by a moulding operation. The panel 10 has a patterned upper surface 72, to give the panel non- slip characteristics and various different patterns may he provided for this purpose. The panel is bound by several edges which are expressly configured to permit the panel to be connected to a plurality of like panels with the various edges interengaged and locked together. En order to fbrm a continuotis area of decking from an array of the panels, any one panel spaced from an edge of the continuous area will be interconnected with six like panels, as will be described hereinafter.

Conveniently, the panel may be divided into five notional sub-areas as shown by the long chain lines marked on figure 1. These areas comprise a central section 13, between chain lines 111 and IV, and two end sections 14 and 15, between chain lines land lIE and IV and VI respectively. Each end section is divided into a respective isosceles trapezium part 16 and 17, between chain lines 11 and HI and IV and V respectively, and a rectangular part 18, 19 between chain lines I and Hand V and VI respectively. Each of these sections will now he described in more detail.

The central section 13 is of rectangular oblong lbrrn, though it could be square, and has a pair of external side edges 21, 22 and a pair of end edges 23, 24.

Each trapezium part 16, 17 has parallel short and long edges 27, 28 and a pair of external oblique edges 29, 30 disposed at the same angles (hut in the opposite senses) to the respective parallel edges 27, 28. The short edges 27 of each trapezium part is in fact coincident with the respective end edge 23, 24 of the central section.

Each rectangular part 1 8, 19 has an internal first edge 33 which is coincident with long edge 28 of the respective rectangular part and an external first edge 34 parallel to internal first edge 33. Each rectangular part also has a pair of parallel external second edges 35, 36 extending at right angles to the first edges 33, 34.

Reference is now made to figure 2 of the drawings. l'he external edges of the panel are configured to enable interengaging connection to the corresponding edges of a second like panel, by the incorporation of a projecting section in the form of a tongue 51 and a recessed section 52 in the form of a channel.

The tongue S I and channel 52 each comprise approximately half of the external edge of the panel and are configured to allow the tongue SI and channel 52 of adjacent panels in an array of panels to interengage.

Reference is now made to figure 3 wherein it can be seen that the tongue 5 I further comprises elongate raised sections 53 on its upper face 58.

The outer edge 54 of the tongue has a bevelled (semi-circular) profile when viewed in cross-section. The tongue 51 further comprises chamfered sections between both the upper and lower planar faces of the tongue 51 and the vertical face of the external edge of the panel 57, one of the chamfered sections 56 is shown in figure 3 located between the upper planar face 58 of the tongue 51 and the vertical face of the external edge of the panel 57. An identical chamfered section is located between the lower planar face of the tongue 51 and the corresponding vertical face of the external edge of the panel.

Reference is now made to figure 4 of the drawings from which it can be seen that the cross-sectional profile of the recessed section 52 is of complementary shape to the overall profile of the tongue 51. The inner end of the recessed section 6! has a semi-circular shape when viewed in cross-section. An elongate groove 62 is incorporated along the length of the recessed section 52. The outer end of the recessed section 63 having a profile complementary to the chamfered sections 56 of the tongue 51.

Reference is now made to figure I, figure 3 and figure 4 of the drawings wherein the elevated areas 71 on the tipper surface 72 of the panel 10 can be seen.

Corresponding recessed areas 73 on the lower surface of the panel 74 can be seen on figure 2.

The elevated areas 71 on the upper surface 72 of the panel 10 have a cone shape with a flattened top 75 as shown in figure 4. The flattened top of the cone is of a smaller diameter than the diameter of the corresponding recessed area 73.

Figure 2 shows elongate indentations 81 on the lower surface of the panel 10 which facilitate the cutting of the panel into smaller sections with the use of appropriate cutting means such as knives. The panels 10 are preferentially made from resiliently deformable plastics material.

Figure 5 shows the interconnection of three panels 90, 9 1 and 92, with the connection between panels 90 and 91 completed and panel 92 in the process of being connected to the other two. As shown, panel 91 is engaged with the left hand upper part (in figure 5) of panel 90, and the panel 92 is being engaged with the right hand upper part of panel 90, as well as with the right hand external first edge 34A of panel 9 I. The right hand first edge 34 of panel 91 incorporates a tongue which is being engaged with a corresponding channel in the left hand edge 34B of panel 92.

Panel 91 has its second edge 36A of one rectangular parE 19 alongside half of the length of a side edge 21 of the central section 13 of panel 90, half the tongue of the side edge 21 being engaged with the corresponding channel of the second edge 36A of panel 91 such that the relevant groove and corresponding raised portion are interlocked. The oblique edges 29, 30 of the two interconnected trapezium parts 16, 17 of the two panels have their respective tongue and channel interengaged and thus their relevant groove and corresponding raised portion are interlocked to prevent relative movement in a direction normal to the plane of the panels. Ilalfofthe side edge 22 of the central section 13 of panel 91 is engaged with the second edge 35 of the rectangular part 18 of the first panel 90, the two panels have their respective tongue and channel interengaged and thus their relevant groove and corresponding raised portion are interlocked. As shown, panels 90 and 91 are locked together by use of the locking mechanism provided on the tongue and channels provided in the form of grooves and corresponding raised portions.

Panel 92 has its left hand external first edge 34B engaged with the right hand external first edge 34A of panel 91 with the respective tongue and channel partly fitted together. As such panel 92 is slidable with respect to panel 91 in the direction of the length of the engaged external first edges 34A and 34B. From the position shown in figure 5, the panel 92 may he slid towards panel 90 to take up the position between panels 90 and 91, with the respective tongue and channel interengaging such that the relevant grooves and correspondillg raised portion interlock to lock all three panel together. Further panels may he fitted to the panels 90, 91 and 92 in the same manner, thus building up a complete array of like panels, all interlocked together. As will be appreciated, there will be no continuous straight line extending along the junctions between the panels. As such, there will he no line of weakness or flexibility, so giving the assembled array of panels high strength and rigidity.

It will also be appreciated that cutting of the panels is facilitated by the provision of the elongate indentatjoiis 81 on the lower planar face of the panels. The cutting of panels 10 along the elongate indentations 81 provided on the lower side of the panels 10 gives sections of panels that can be used at the periphery of an array to give a straight edge to the array.

When the panels are produced from a resiliently deformabje plastics material such as PVC or polypropylene and the locking mechanism described herein is utilised, then the panels interlock to form an array which is effectively waterproof, i.e water and water vapour cannot pass through the array from below the lower face of the array to above the upper face either through the panels or through the joilits between the face panels forming the array. Additionally, a waterproof sealant, such as silicone, can be used to seal the points where adjacent tiles meet at the periphery of the array. This prevents water tracking from the edges of the array along the joints between adjacent tiles into the centre of the array.

The use of a resiliently deformable plastic to produce the panels allows an array of the panels to flex when pressure is applied to the panels when they are used on uneven surfaces, this helps to prevent individual panels becoming detached from each other in such circumstances Panels of this particular design are expected to prove especially useful in the production of floorings for marques and/or even small tents where the evaporation of water vapour from the ground into the enclosed area is undesirable, or alternatively the passage of materials spilt within the tent/marquee to the ground below such as oil, wine and other liquids is to be prevented. Additionally they are expected to prove especially useftul for the provision of waterproof flooring in bathrooms.

In order to separate panels from each other, a user lifts the tile to be removed from the periphery of the array while holding the adjacent panel in a stationary position and whilst simultaneously pulling the tile in a direction away from the centre of the array but in generally the same plane as the array. The production of the panel 10 from resiliently deformable material and the incorporation of the elongate groove 62 allows the section of the panel 95 beyond the groove 62 as shown in figure 41 to flex when the panel to be removed is lifted, thus assisting the separation of the panels to be separated from the neighbouring panels. The separation of the panel froni the periphery of the array is further assisted by the provision of the chamfer 56 which acts as a pivot point as the panel is lifted, thus further facilitating the separation of the panel from its neighbour(s) In an alternative embodiment, a metal insert 91, as shown in figure 6 of the drawings may be embedded within the panels, at the time of moulding thereof. This example of an insert is pre- fornied from metal strip, such as steel in order to have the same shape as the panel when viewed in plan, but of such size such that the insert will lie adjacent the various edges of the pane!, but will he covered with the plastics material to impart corrosion resistance to the insert. The insert 91 IS manufactured by welding together various strips pre- formed to have the required external shape, together with various reinforcing pieces 93 internally within that shape. Wheii such a metal insert 91 is used the panel is preferentially of sufficient thickness to allow the insert to be fully embedded.

The insert has four tubes 94 adjacent the corners of the central section and arranged with their axis parallel and normal to the main area of the panel. These tubes 94 may be used for the attachment of components to the panels by drilling through the plastics material or by blanking the plastics material from the tubes during moulding of a panel. When heavy loads are to he applied to sLlch reinforced panels it may be necessary to provide further means to maintain the relative position of adjacent panels, i.e. the secondary locking means disclosed in earlier application PCT/0B2004/004200 The insert may be made of other materials besides metal, eg. hard plastics material, carbon or glass reinforced plastics moulding. Rigid reinforced panels of this type may be particularly useful in situations where arrays of panels are to have large loads applied to the array, for instance, by the passage of vehicles such as lorries over a roadway made from an array of such panels.

It will he appreciated by those skilled in the art that various modifications niay he made to the invention without departing from the scope of the invention claimed herein.

The panels may be made from rigid material, such as hard plastic, wood, carbon fibre or glass fibre.

A mechanism may be used to lock the panels together such that they may only be disassembled by the destruction of the locking mechanism, as shown in figure 6.

Alternative shapes of raised and lowered portions may be used, for instance, circular or square shaped raised and lowered portions may he provided along the lengths of the projecting and recessed sections.

Claims

I. A surface covering panel comprising a central section and two opposed end sections, the central section being of generally rectangular form with two parallel external edges and two parallel end edges, each end section having an isosceles trapezium part conjoined to a rectangular part, the trapezium part having parallel long and short edges and a pair of external oblique edges, and the rectangular part having a pair of parallel first edges and a pair of external second edges, the short edge of the trapezium part conjoining an end edge of the central section and the long edge conjoining a first edge of the rectangular part, the other first edge of the rectangular part being external, and the length of either second edge of the rectangular parts, whereby a panel may be tilted together with other like panels in an array by engaging an oblique edge of an end section of one panel with an oblique edge of an end section of a second panel, a second edge of the rectangular part of the engaged end sections of each of' the two panels engaging the respective side edge of the central section of the other panel, and a third panel is engaged with said two panels in a similar manlier so that an end section thereof engages an end section of the one panel and the external flrst edge of said end section of the third panel engages the corresponding external first edge of the second panel, at least some of the external edges of the panel are configured for interengaging connection to the corresponding edges of a second like panel by means of the external edges of the panel which further comprise a projecting section and a recessed section characterised in that said projecting section and recessed section have interlocking raised portion(s) and lowered portion(s), such that in use, when the projecting sections and recessed sections of' two panels are engaged, the raised portion(s) interlock(s) with a corresponding lowered portion(s) on an adjacent panel to lock the panels together.
2. A panel as claimed in claim I wherein the lowered portion comprises a groove.
3. A panel as claimed in either one of claim 1 or claim 2 wherein the projecting section and recessed section each constitute approximately half of the engageabje external edges of the panel.
4. A panel as claimed in claim 3 of the preceding claims wherein the raised portion and the corresponding grooved portion are incorporated along the length of the projecting section and corresponding recessed section as a single groove and correspondingly shaped raised portion.
5. A panel as claimed in any one of the preceding claims, wherein the panel is made from a resiliently deformable material such as plastics material.
6. A panel as claimed in any preceding claim wherein the panel further comprises elevated areas on an tipper planar surface and corresponding recessed sections on a lower planar surface, the recessed section being of larger cross-section in the plane of the surface than the corresponding elevated area.
7. A panel as claimed in any preceding claim, wherein the panel further comprises elongate indentations on a planar surface of the panel to facilitate the cutting of the panel into smaller sections.
8. A panel as claimed in any preceding claim wherein the shape of the raised portion(s) and lowered portion(s) enables the panels to be releasably engageable.
9. A panel as claimed in any preceding claim, wherein the projecting section and the recessed section further comprise a bevelled zone and a correspondingly shaped slot which abut each other when the panels are in use.
10. A panel as claimed in any preceding claim, wherein the projecting section further comprises a chamfer along the length of at least one of the joints where the external edge olthe panel meets the projecting section.
11. A method of building up a substantially planar array of a plurality of individual panels using panels according to any one of the previous panels, wherein: - the second edge of one section of a first panel is brought into engagement with one side of the central section of a second panel, a second edge of an end section of the second panel simultaneously coming into engagement with a corresponding side edge of the central section of the first panel, said projecting section lOcating in the respective recessed section of the first and second panels; - the two panels are moved relatively to bring the adjacent oblique edges of the respective end sections into engagement and the respective raised portion and grooved portion interlock to lock together the first and second panels; - the extern first edge of an end section of a third panel is brought into engagement with the first edge of the end section of the second panel already engaged with the first panel; - the engaged first edges of the second and third panels are slid relatively to bring the second edge of the end section of the third panel into engagement with the side edge of the central section of the first panel already engaged by the second panel, said projectiiig section locating in the respective recessed section of the first and third panels; - the respective raised portion and grooved portion interlocking to lock together the first and third panels thereafter to restrain relative separating movement between all three panels.
12. A method of assembling an array of panels as claimed in claim 11, wherein the projecting section and the recessed section each comprise approximately half of the engageabje external edge of the panel and an appropriate waterproof sealant is used to seal points where adjacent tiles meet at the periphery of the array.