Structural underlayment support system for use with paving and flooring elements

BACKGROUND OF THE INVENTION

This invention relates in general to paver brick support systems. Discrete paving elements, such as bricks and stones, are used for outdoor patios and other similar structures. The pavers can provide a durable and aesthetically pleasing surface. Such a paving system is for example known from <patcit id="pcit0001" dnum="DE20119065U1"><text>DE 201 19 065 U1</text></patcit> disclosing a drainage composite board. The pavers are usually supported on a base layer to insure that the pavers provide a level surface when installed. These paved surfaces are susceptible to the environment and other forces that sometimes cause the supporting base of the pavers to shift or otherwise settle over time. When this happens, the paving elements may also shift, causing the surfaces to become uneven and difficult to traverse. Uneven surfaces can present difficulties for supporting objects in a stable condition.

Furthermore in the state of the art artificial turf systems of the type used in athletic fields, ornamental lawns and gardens, and playgrounds are known. For example <patcit id="pcit0002" dnum="US20080176010A1"><text>US 2008/0176010 A1</text></patcit> being directed to a base for a turf system discloses such a system.

It would be advantageous if there could be developed an improved structure and method for supporting and installing paving elements.

SUMMARY

This invention relates a paving system for paving or flooring with the features of claim 1, including a top layer of a plurality of paving elements, and an underlayment support layer of polymeric material in the form of panels, the panels being suitable to support the paving elements, the panels being made of a core with a top side and a bottom side. The top side has a plurality of spaced apart, upwardly oriented projections that define channels suitable for water flow along the top side of the core when the underlayment layer is positioned beneath the layer of paver elements and the bottom side includes a plurality of spaced apart, downwardly oriented projections that define channels suitable for water flow when the underlayment layer is positioned beneath the layer of paver elements.

There is also described a paving system for paving or flooring including a top layer of a plurality of paving elements, and an underlayment support layer of a polymeric material configured into panels, the panels being suitable to support the paving elements, the panels having a generally planar support surface and a recovery characteristic such that a deformation from a concentrated compressive load applied for a short duration returns the support surface to a generally planar condition.

There is also described a paving system for paving or flooring, the paving system including a top layer of a plurality of paving elements, and also including an underlayment support layer of a polymeric material configured into panels, the panels being suitable to support the paving elements, and the panels being porous to the flow of fluids.

According to this invention there is also provided a paving system comprising native soil, a layer of bedding sand, an underlayment support layer of a polymer material, and a layer of paving elements.

There is also described a method of installing a paving system, the method including excavating surface material and prepare a substantially level surface on native soil, applying a layer of bedding sand to the native soil, applying an underlayment support layer of polymer material to the bedding sand, and applying a layer of paving elements.

According to this invention there is also provided a paving system for paving or flooring, the paving system including a top layer of a plurality of paving elements, and an underlayment support layer of a polymeric material configured into panels, the panels being suitable to support the paving elements, and the panels being made of recyclable material.

Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

<ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Fig. 1</figref> is a perspective view of a paving system having an underlayment support layer.</li><li><figref idref="f0002">Fig. 2</figref> is an enlarged elevational view, in cross section, of a paving system not forming part of the present invention.</li><li><figref idref="f0002">Fig. 3</figref> is an elevational view of an alternative embodiment of the paving system not forming part of the present invention.</li><li><figref idref="f0003">Fig. 4A</figref> is a plan view of an underlayment support layer having interlocking sections.</li><li><figref idref="f0003">Fig. 4B</figref> is a plan view of an alternative embodiment an underlayment support layer having interlocking sections similar to <figref idref="f0003">Fig. 4A</figref>.</li><li><figref idref="f0003">Fig. 5</figref> is an elevational view of an embodiment of an underlayment support layer having a flanged interlocking structure.</li><li><figref idref="f0004">Fig. 6A</figref> is an enlarged elevational view of an underlayment support layer having a fused bead structure.</li><li><figref idref="f0004">Fig. 6B</figref> is a schematic view illustrating the substantially water impervious nature of the underlayment support layer.</li><li><figref idref="f0004">Fig. 7A</figref> is an enlarged elevational view of an underlayment layer having a bonded bead structure that includes interstitial spaces between the beads.</li><li><figref idref="f0004">Fig. 7B</figref> is an enlarged elevational view of an alternative embodiment of an underlayment support layer having a fused bead structure and further having drainage holes formed therethrough.</li><li><figref idref="f0004">Fig. 7C</figref> is a schematic view illustrating the porosity of the underlayment support layer.</li><li><figref idref="f0005">Fig. 8</figref> is an exploded perspective view, in partial cross section, of an alternative embodiment of a paving system, which is not part of the present invention, having an underlayment support layer.</li><li><figref idref="f0006">Fig. 9</figref> is a plan view of an underlayment support layer panel suitable for providing support for paving elements in a paving system.</li><li><figref idref="f0006">Fig. 10</figref> is an enlarged view of a portion of the panel of <figref idref="f0006">Fig. 9</figref>.</li><li><figref idref="f0007">Fig. 11</figref> is an elevational view of the panel of <figref idref="f0006">Fig. 9</figref>.</li><li><figref idref="f0007">Fig. 12</figref> is an enlarged view of an end portion of the panel shown in <figref idref="f0007">Fig. 11</figref>.</li><li><figref idref="f0008">Fig. 13</figref> is a perspective view of an alternate form of the underlayment support layer, which is not part of the present invention.</li></ul>

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, there is illustrated in <figref idref="f0001">Fig. 1</figref> a paving system, shown generally at 10. While described in the context of an exterior or outdoor structure, the paving system 10 may be applicable to interior systems as well, as will be explained below in detail. The paving system 10 includes a plurality of paving elements 12 having an exposed surface 12A that is suitable for activities requiring a supportive surface, such as pedestrian activities or vehicular activities. The paving system 10 may be, for example, a sidewalk, a patio, or a driveway. The paving elements 12 are illustrated as paving bricks, though other paving elements such as, for example, natural stones, flagstones, river rock, artificial stones, concrete tiles, and the like may be alternative equivalent elements. The paving elements 12 may be porous to the flow of water or other fluids, or may be impervious. The paving system 10 may alternatively be an interior support system where the paving elements 12 may alternatively be rubber or wooden blocks applied in an interior environment, such as is used in construction of factory floor systems.

As shown in <figref idref="f0001">Fig. 1</figref> an optional joint sand treatment 14 is applied to the paving elements 12. The joint sand treatment 14 is composed of sand, which may be loose or compacted. Alternatively, the joint sand treatment can be any natural of artificial medium such as, for example, ground rubber, clay, dirt, silica particulate, crushed glass, and the like. A mixture of sand and polymer material can be used, where the mixture is formulated to set up or harden into a hard component of the paving system 10. Alternatively, the paving elements 12 may be arranged so that the sides, or portions thereof, are touching such that the joint sand treatment 14 is not disposed between adjacent elements 12.

The paving elements 12 are installed above an underlayment support layer 16, which is comprised of a foamed material. More specifically, the underlayment layer 16 shown in <figref idref="f0001">Fig. 1</figref> is formed from a plurality of polymer beads 30 (shown in <figref idref="f0004">Fig. 7A</figref>) that are bonded together to form a unitary body or block. The polymer beads 30 may be formed from any material, but in various embodiments the beads are formed from polypropylene, polyethylene, or polystyrene, or mixtures of those materials. Methods of forming the foamed underlayment support layer 16 will be disclosed below. In a non claimed embodiment, the underlayment support layer 16 can be made of non-foamed polymeric material. While the paving system 10 is described with the underlayment support layer 16 in the form of separate panels, it is to be understood that the underlayment support layer 16 can just as well be applied in the form of a roll of the material. Accordingly, the term "panel" includes the material in the form of continuous material that can be unrolled to form the underlayment support layer 16.

The thickness of the underlayment layer 16 can vary, depending on the particular configuration of the support system 10 for which the underlayment layer is to be used. In one embodiment the thickness is in the range of from about 0.25 inches (6 mm) to about 1.25 inches (32 mm). In another embodiment, the underlayment layer 16 is a thin sheet with a thickness within the range of form about 0.0625 inch (1.6 mm) to about 0.25 inch (6 mm), and in particular about 0.125 inch (6 mm). In yet another embodiment, the underlayment layer is thicker than 1.25 inches (32 mm).

The paving system 10 rests on the underlying ground, referred to as the substrate layer 20. The substrate layer 20 may be dirt, sand, clay, concrete, crushed stone, and the like. The substrate layer 20 is according to the present invention native soil but in embodiments that are not part of the present invention it may be compacted native soil or may be a graded and/or compacted aggregate base layer. In one embodiment, a layer of leveling material, such as a thin layer of bedding sand (not shown in <figref idref="f0001">Fig. 1</figref>), can be applied to the substrate layer 20 before the underlayment support layer 16 is added.

As shown in <figref idref="f0001">Fig. 1</figref>, a layer of bedding sand 17 is applied to the underlayment support layer 16. This layer is optional, but if applied it provides a smooth, relatively level bed or surface on which the paving elements 12 are laid. The bedding sand layer 17 can optionally act as a filter layer that can trap contaminants passing through the paving system 10. Such a filter layer may further include piping to transfer effluent, whether filtered or not, away from the support system 10. The bedding sand layer 17 may alternatively include a biological organism capable of breaking down pollutants into harmless matter that may be further filtered out prior to introduction of drainage water into the water table. The bedding sand 17 can be of any suitable particulate material, such as the material used for the joint sand 14.

Optionally, a soil barrier layer 18 can applied between the underlayment layer 16 and the underlying soil or substrate 20. The soil barrier layer 18 may be a geo-textile material such as, for example, a woven or nonwoven fabric that is water permeable. The purpose of the geo-textile material is to substantially preclude the mixing of the material above and below the geotextile layer. For example, the layer can substantially preclude the mixing of a layer of bedding sand above the geotextile material with the sub-soil layer beneath the geotextile layer. In an embodiment not making part of the present invention the layer 18 may be made of a solid material that is water impervious. The desirability of having water flow through the various layers or having the water diverted to other locations may be partially dictated by the type and condition of the substrate layer 20.

As shown in <figref idref="f0004">Fig. 7B</figref>, the underlayment layer 116 of one embodiment is similar to the analogous layer 16 of <figref idref="f0001">Fig. 1</figref>. The underlayment support layer 116 is formed from beads 130, that are made of polymers such as polypropylene, polyethylene, and polystyrene, and the like. The fused beads 130 may alternatively be a mixture of polymer materials. The beads 130 are expanded to reduce their density. The beads 130 may be molded under heat and compression to bond the beads together, and to compress the beads to the extent sufficient to substantially remove the interstitial voids between the beads. Prior to the molding process, the fused beads 130 can be initially formed together by localized melting and fusing of the adjacent surfaces, although other bonding systems can be used. The fused beads 130 may also require no adhesive mixture.

According to the invention the beads are originally manufactured as tiny solid plastic pellets, which are later processed in a controlled pressure chamber to expand them into larger foam beads having a diameter within the range of from about 2 millimeters to about 5 millimeters. The foam beads are then blown into a closed mold under pressure so they are tightly packed. Finally, steam is used to heat the mold surface so the beads soften and melt together at the interfaces, forming the underlayment support layer 116 as a solid material that is water impervious. Other methods of manufacture not being part of the invention can be used, such as mixing the beads with an adhesive or glue material to form a slurry. The slurry is then molded to shape and the adhesive cured.

Referring now to <figref idref="f0006 f0007">Figs. 9-12</figref>, there is illustrated a underlayment support layer 316 that can be used with various paving systems. The panel 316 is comprised of a core 340, a top side 342 and a bottom side 344. The top side 342 contains a plurality of spaced apart, upwardly oriented projections 350, and the bottom side 344 contains spaced apart downwardly oriented projections 370. In embodiments not making part of the present invention, the projections need not be on both the top side and bottom side, but can be on one or the other in some embodiments. The projections 350 have truncated tops that form a plane that defines an upper support surface 352 configured to support the paving elements. The projections 350 do not necessarily require flat, truncated tops. The projections 350 may be of any desired cross sectional geometric shape, such as square, rectangular, triangular, circular, oval, or any other suitable polygon structure. The projections 350 may have tapered sides extending from the upper support surface 352, or may have vertical sides. The projections 350 may be positioned in any suitable arrangement, such as a staggered arrangement, and may be any height desired. In one embodiment the projections 350 are in the range of about 0.5 millimeters to about 6 millimeters. One of the advantages of the use of downwardly oriented projections is that they can prevent the panel from sliding laterally on the sand or subgrade layer below it, or at least substantially reduce such sliding.

The sides of adjacent projections 350 cooperate to define channels 356 that form a labyrinth across the panel 350 to provide lateral drainage of water that migrates down from the paver elements. The channels 356 are suitable for water flow along the top side of the panel 316 when the underlayment layer is positioned beneath a layer of paving elements. Even though the channels are often packed with particulate material, such as the bedding sand 17, the channels are still beneficial in providing a path for the flow of water draining through the paving system 10. The water can flow through the sand in the channels.

According to the invention the channels 356 have drain holes 358 spaced apart and extending through the thickness of the panel 316. Projections 370 are according to the invention likewise formed on the bottom side 344 of the panel 316, with the projections forming bottom channels 376. The channels 376 are suitable for water flow along the bottom of the panel 316. The drain holes connect the top channels 356 for fluid communication with the bottom channels 376.

The size of the drainage holes 358, the frequency of the drainage holes 358, the size of the drainage channels 356 on the top side 342 or the channels 376 on the bottom side 344, and the frequency of the channels 356 and 376 provide a design where the channels 356, 376 can be aligned with each other to create a free flowing drainage system. The size and quantity of the top side channels 356, bottom side channels 376, and drain holes 358 can provide dispersion of fluid flow through the paving system sufficient to reduce soil erosion beneath the paving system.

According to the invention the panels 316 are provided with a mechanism for interconnection with each other. One such mechanism is shown in <figref idref="f0007">Figs. 11 and 12</figref>. The panel 316 includes on two of its edges an overlapping portion or flange 380 and a corresponding recessed portion 382. These features are configured to mate with each other in an overlapping manner on adjacent panels 316 to provide an interconnection with each other. Other connection mechanisms can be used.

The bottom side 370 projections can be the same size as the size of the top side projections 350, or may be a different size. A drainage system, not shown, can be connected to the channels 356 and 376 for the removal of fluids.

The deformation characteristics of the underlayment support layer panel 316 may be of particular interest for some applications. Advantageously, the panel 316 is soft enough that it allows the installer of the paving system 10 to comfortably kneel on the panel 316 in order to work on the installation of the pavers. This requires the panel 316 to be able to deform when under load to distribute the forces to the point that the kneeling installer is comfortable. In one embodiment not covered by the invention, the panels, while being suitable to support the paving elements, have a generally planar support surface and a recovery characteristic such that a deformation from a concentrated compressive load applied for a short duration returns the support surface to a generally planar condition. In a specific embodiment, the deformation is at least 5 percent under the concentrated compression load. It is advantageous, however, if the deformation is not so great as to form a permanent indentation or deformation in the underlayment support layer panel 316. In a specific embodiment the deformation is less than or equal to 10 percent under the concentrated compression load.

EXAMPLE I An underlayment support layer was formed by placing expanded polypropylene beads into a mold under pressure and subjecting the confined beads to a steam application sufficient to soften and melt together the beads at interfaces between the beads. The panel had a thickness of 20.71 mm, and a density of 55 g/l. The panel was subjected to a load to simulate the load of a 235 pound paving system installer. The load selected was applied to the surface over an area of approximately 3.14 square inches, using a tool with a square impact surface 1.414 inches (3.59 cm) on a side. The impact surface is equivalent to a 2 inch diameter area, to represent the load applied by the worker kneeling on the underlayment support layer 16 on one knee, without knee pads. The load applied was 150 pounds (68.1 kg), which is equivalent to 75 psi (pounds per square inch) (517.5 kPa). The load was applied for 10 seconds, and then removed. The deformation of the panel was measured while the load was being applied, immediately after the load was removed, and at a time 2 hours after the load was removed. The results are shown in Table I as follows: <tables id="tabl0001" num="0001"><table frame="none"><title>TABLE 1</title><tgroup cols="2" colsep="0" rowsep="0"><colspec colnum="1" colname="col1" colwidth="40mm" /><colspec colnum="2" colname="col2" colwidth="13mm" /><tbody><row><entry>Deformation under load</entry><entry align="center">8.4 %</entry></row><row><entry>Deformation after 2 hours</entry><entry align="center">6 %</entry></row></tbody></tgroup></table></tables>

The compression of the panel immediately after the load was removed was 1.74 mm, and the compression after 2 hours was 1.25 mm.

Other sample foams were subjected to the same loading procedure. The panels included a Styrofoam product from a Styrofoam cooler (having an initial thickness of 17.19 mm), a Styrofoam insulation sheet (having an initial thickness of 17.7 mm), and a sample of Arcel (having an initial thickness of 20.28 mm), which is a combination of Styrofoam and EPP (expanded polypropylene). The results of the testing are shown in Table II as follows: <tables id="tabl0002" num="0002"><table frame="none"><title>TABLE II</title><tgroup cols="3" colsep="0" rowsep="0"><colspec colnum="1" colname="col1" colwidth="34mm" /><colspec colnum="2" colname="col2" colwidth="37mm" /><colspec colnum="3" colname="col3" colwidth="15mm" /><tbody><row><entry>Styrofoam cooler</entry><entry>deformation under load</entry><entry>35.6 %</entry></row><row><entry>Styrofoam cooler</entry><entry>2 hour deformation</entry><entry>33.5%</entry></row><row><entry>Styrofoam insulation</entry><entry>deformation under load</entry><entry>24.2%</entry></row><row><entry>Styrofoam insulation</entry><entry>2 hour deformation</entry><entry>22.5%</entry></row><row><entry>Arcel sample</entry><entry>deformation under load</entry><entry>29.5%</entry></row><row><entry>Arcel sample</entry><entry>2 hour deformation</entry><entry>25.5%</entry></row></tbody></tgroup></table></tables>

In one embodiment of the paving system, the deformation is less than 7 percent two hours after removal of the compression load from the panel. In another embodiment of the invention the density of the panel is within the range of from about 40 to about 70 g/l. In a specific embodiment, the density of the panel is within the range of from about 50 to about 60 g/l.

Another way to assess the deformation characteristic of the underlayment support layer is to determine the amount of permanent compression imparted to the underlayment support layer when subjected to various compression loads during normal installation . Advantageously, the deformation from typical loads such as the kneeling installer or an installer walking on the underlayment support layer does not impart a permanent defect or deformity in the surface of the underlayment support layer. Depressions in the surface of the underlayment support layer of significant size will cause imperfections in the smoothness of the upper surface of the paving elements 12, or may allow undesirable movement of the paving elements. In one embodiment, the depression in the surface of the underlayment support layer is less than about 2.0 mm when subjected to a compression load of 75 psi 517.5 kPa) applied for 10 seconds over a 2 inch (5 cm) diameter area, when measured 2 hours after removal of the load.

The data above shows that the underlayment support layer panels 16 of Example I result in relatively minimal deformation to the upper surface of the panels during the types of loading normally encountered during installation. In contrast, the alternative materials when tested resulted in deformations that were significant in their magnitude, and would likely result in a defective installation. The surface imperfections would likely result in an unacceptably uneven upper surface for the paving elements 12. Also, such a deformed underlayment support layer would likely result in some of the paving elements 12 being so poorly supported that they would rock or wobble when applied with a normal load of a pedestrian or vehicle.

An advantage of the paving system 10 is that the need for excavating the native soil and replacing the native soil with up to 4 inches (10 cm) of a traditional compacted aggregate replacement base is eliminated. Also, the paving elements can be easily positioned and aligned by sliding on the surface of the underlayment support layer panels, assuming no bedding sand layer is being used. Further, the use of the underlayment support layer panels provides great load spreading over the native soil. It is also to be understood that the underlayment support layer 16, 316 can be placed over traditional aggregate bases of crushed stone and the like. it is to be understood that it may be advantageous to apply a layer of leveling sand on the soil or subgrade prior to applying the underlayment support layer 16.

In some applications of paving systems there is a need for providing the system with the ability to drain rain water downward to the underlying water table rather than having the rain water flow away along the surface of the ground and be carried away by a storm drain system. As shown in <figref idref="f0006">Figs. 10</figref> and <figref idref="f0007">12</figref>, the underlayment support layer 316 includes the drainage holes 358 and the upper and lower channels 356, 376. These elements of the underlayment support layer 316 allow water to flow downward through the paving system and into the sub-soil for eventual replenishment of the water aquifer. It is to be understood that the paving elements themselves can be porous to enhance the downward flow of rain water. Additionally, such a dispersed flow of water through the paving system 10 reduces soil erosion by allowing the water to pass through at a reduced velocity and force. Traditional installation techniques require excavation of up to 10 cm or more of native soil, and replacement of that soil with an equal amount of compacted aggregate. While the compacted aggregate provides a solid base of support for the paving support system, the compacted aggregate substantially prevents downward percolation or flow of rain water into the underlying soil. In this respect, the paving support system 10, which allows substantial downward flows of rain water, provides an advantage over conventional systems.

As described above, the underlayment support layer 16, 316 can be made of fused expanded polymer beads. In another embodiment, not covered by the claimed subject matter, the underlayment support layer can be made by gluing or fusing expanded polymer beads in an open matrix that includes interstitial spaces. As shown in <figref idref="f0004">Fig. 7A</figref>, the polymer beads 30 may alternatively to the claimed subject matter be mixed with an adhesive 32 to bond the polymer beads together. The block of bonded beads allows interstitial voids 34 to form between adjacent beads 30. The bead and adhesive mixture is formed into a shape, such as a large rectangular mass (not shown), and may be compressed to form the beads into a unitary body or block. The compression of the block is controlled so that it does not eliminate the interstitial voids 34 formed between the adjacent beads 30. Though illustrated as spherical, the beads 30 may be any shape or a random amorphous shape if desired.

Referring now to <figref idref="f0002">Fig. 3</figref>, which is not part of the present invention, the support system 100 is illustrated having a fused bead underlayment 116 and a fluid drainage system 122. The support system 100 is an embodiment that may be used in both exterior and interior applications. As an interior application, the support system 100 may be a block floor in a manufacturing facility. Paving elements 112 may be rubber or wooden blocks, though other paving elements can be used. The paving elements 112 may be embedded into or placed on top of a bedding sand layer 117 that may be a chemically resistant or inert material, such as for example ground rubber, silica, or sand. Joint sand 114 can also be used. The paving elements 112 may be spaced apart or abutting adjacent paving elements if so desired. The support system 100 is configured to allow water and other fluids, such as for example machine oils or hazardous chemicals, to drain through to the underlayment layer 116. The drainage system 122 may be a series of perforated tiles or pipes and may also include pads 124 and drainage channels 126, formed on one or more surfaces of the underlayment 116.

A plurality of spaced apart drain holes 134 are formed through the underlayment layer to provide fluid communication between upper and lower surfaces of the underlayment 116, as illustrated in <figref idref="f0004">Fig. 7B</figref>. In the embodiment shown, a fluid impervious barrier layer 118 is placed between the underlayment 116 and a substrate 120, as shown in <figref idref="f0002">Fig. 3</figref>. The substrate 120 may be similar to the substrate 20, described above. The support system 100 of <figref idref="f0002">Fig. 3</figref> allow fluids to pass through the bedding sand layer 117 and drain through the underlayment layer 116 to the barrier layer 118. The barrier layer 118 may be a water impervious layer, such as a rubber liner, vinyl liner, and the like. The fluids are then channeled along the barrier layer 118 to the drain system 122 for collection and processing. Such a support system 100 may allow factory machine oils, water, or other spilled contaminants to be washed or otherwise collected and separated in order to prevent contamination of subsurface ground water and other soil layers.

Referring now to <figref idref="f0002">Fig. 2</figref>, not showing the claimed subject matter but being helpful in understanding the same under certain conditions, a substrate layer 220 may provide a better foundation for a layer of paver elements if water is prevented from passing through its underlayment layer 216. For example, where the support of the substrate layer 220 may be affected by settling due to water flow, an underlayment 216 and/or a barrier layer 218 may be configured to be water impervious. Such an impervious support system 200 is shown in <figref idref="f0002">Figs. 2</figref>, <figref idref="f0004">6A, and 6B</figref>. The support system 200 includes the support surface 212, shown as paving elements which may be similar to paving elements 12 and 112, though such is not required. The paving elements 212 are illustrated as being partially embedded in a joint sand material 214, which may be similar to the joint sand materials 14 and 114, described above, though other materials, whether ground or naturally granular, may be used. A layer 217 of bedding sand is also shown. The underlayment layer 216 has no holes or voids that allow water drainage. Such a system 200 may be particularly advantageous when place over unstable soils, such as a clay soil.

Referring now to <figref idref="f0005">Fig. 8</figref>, there is illustrated another embodiment which is not part of the present invention, of a support system for paving and flooring elements, shown generally at 400. The flooring and paving support system 400 includes paving elements 412, which may be any form of discrete, individual paving elements, such as those previously described above. An underlayment layer 416 is provided in order to disperse concentrated loads from the paving elements onto a substrate layer 420 such as for example, native soil, compacted stone, or sand. The underlayment layer 416 may be an extruded pad having a homogenous cross section. Alternatively, the underlayment layer 416 may be formed from recycled materials, such as ground rubber from shoe soles, tires, and the like. The ground, recycled material may take the form of flakes 414 that are packed together. Such a ground underlayment 416 may be bonded together and exhibit a water impervious characteristic, similar to that depicted in <figref idref="f0004">Fig. 6B</figref>. Alternatively, the flakes 414, forming the ground underlayment 416, may include interstitial voids (not shown) that allow water to pass through the thickness of the underlayment 416. The interstitial voids may be formed between adjacent flakes 414 that are, themselves individually, water impervious. Alternatively, the flakes 414 themselves may be porous and may be bonded together such that the underlayment 416 allows water to pass through. The advantage of the underlayment layer 416 is that is sufficiently rigid to disperse the concentrated loads that are applied from the paving elements onto a larger surface area of the native soil.

Referring now to <figref idref="f0003">Fig. 4A</figref>, the underlayment layer 16 is formed into discrete panel sections 50 that may be assembled to cover the entire substrate layer, such as substrate 20. The panel sections 50 are separated along boundary lines 52. The panel sections 50 may be formed into puzzle-like pieces having locking tabs 54 that engage correspondingly shaped slots 56. The panel sections 50 are interlocking to prevent separation along the surface of the substrate 20 during installation. Referring now to <figref idref="f0003">Fig. 4B</figref>, the underlayment layer 116 may be similarly divided into panel sections 15 that include pads 124 and channels 126 formed onto the surface.

<figref idref="f0003">Fig. 5</figref> illustrates an embodiment of a panel section 350 having a tongue-and-groove configuration, A tongue 354 axially engages (in the direction of the arrow) a corresponding groove 356 to prevent lateral relative movement of mating panel sections. Alternatively, the underlayment 16, 116, and 216 may be a rolled material that is laid out onto the ground. The rolled material may have puzzle-like tabs and slots or may have tongue-and-groove edges if desired. Alternatively, any edge locking arrangement may be used between adjacent panels.

The support system 10 of <figref idref="f0001">Fig. 1</figref> uses the underlayment layer 16 shown in <figref idref="f0004">Figs. 7A and 7B</figref>. The underlayment layer 16 is formed from a plurality of polymer beads 30 that are bonded together to form a unitary body or block. In a non claimed embodiment, the underlayment layer 16 may also include reclaimed scrap bead material, termed "regrind", that may include sections of previously cured bead and adhesive mixture that is ground or otherwise broken into smaller pieces and introduced into the new bead and adhesive mixture. In one embodiment, the underlayment support layer is made of fully recyclable material, such as polypropylene material such that the reclaimed material can be re-melted, extruded into pellets which are then expanded into new beads for use in steam chest molding of any expanded polypropylene part including new underlayment parts 16.

Example III (not part of the present invention)

One example of a paver system includes the following layers: compacted subgrade, geotextile material, bedding sand, underlayment support layer panel, and layer of paving elements. The geotextile material is optional, the bedding sand can be either compacted or uncompacted, and the layer of paving elements can optionally be treated with sand or a polymer sand material.

Example IV

(not part of the present invention)

In another example, the paver system includes the following layers: compacted subgrade, geotextile material, an optional leveling sand layer, underlayment support layer panel, bedding sand, layer of paving elements and joint sand. The geotextile material is optional, the bedding sand can be either compacted or uncompacted, and the joint sand can be with or without polymer treatment.

Example V

In yet another example, the paver system includes the following layers: subgrade, thin compacted stone sub-base, geotextile material, bedding sand, underlayment support layer panel, and layer of paving elements. The geotextile material is optional, and the layer of paving elements can optionally be treated with sand or a polymer sand material.

Example VI

In an additional example, the paver system includes the following layers: subgrade, thin compacted stone sub-base, geotextile material, underlayment support layer panel, bedding sand, and layer of paving elements. The geotextile material is optional, and the layer of paving elements can optionally be treated with sand or a polymer sand material.

It is to be understood that in some applications of the paving support system 10, a perimeter restraint or edging system, not shown, can be employed.

<figref idref="f0008">Fig. 13</figref> is a perspective view of an alternate form of the underlayment support layer, which is not part of the present invention. The underlayment support layer does not necessarily have to be a foamed layer, and can instead be a different polymer layer. For example, as shown in <figref idref="f0008">Fig. 13</figref>, a molded plastic support porous grid layer 816 can be used. The molded plastic porous grid includes a lattice network 818 formed by elements 820. The network 818 includes openings 822 for the flow of fluid. Attachment connections 824 can optionally be provided to connect multiple panels. It is to be understood that the polymeric material of the underlayment support layer can take many different forms.

The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated, within the scope of the appended claims.