GROUT MEMBER FOR MODULAR FLOORING ASSEMBLIES

Abstract

Provided is a grout member for a modular floor. The grout member includes a core having a wedge shape, wherein the core consists of a horizontal strut interconnecting two vertical supports. A flange extends from each vertical support to position and secure the grout member in position The core supports a surface section which is oriented toward the user. The modular floor is as assembled by interconnecting modular flooring assemblies that include a flooring component, such as tile, wood or other materials commonly used in flooring applications, and subsequently inserted grout members in the gaps formed by the components

Description

This application is a continuation-in-part of PCT/JUS06/38379 filed Oct. 3, 2006, which claims the benefit of U.S. patent application Ser. No. 11/432,873 filed May 12, 2006, which claims the benefit of U.S. Provisional Application No. 60/723,578 filed Oct. 4, 2005 and to U.S. Provisional Application No. 60/733,686 filed Nov. 4, 2005. The above identified applications are each hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a grout member for a modular flooring assembly. More particularly, the present invention relates to a replaceable, non-bonded grout member retained in position, through functional forces, between two modular floor components.

BACKGROUND

Installing a conventional tile floor is a complicated procedure requiring expertise and craftsmanship The process, which typically involves the use of “fill-in” grout, may require several hours or days of drying time, during which time the floor must not be used. Many of the modular flooring assemblies disclosed in the prior art have not been fully successful, due at least in part to a failure to provide a robust, flexible, serviceable grout component. As such, some prior art modular flooring systems allow tiles to shift or migrate resulting in unacceptable appearance and performance, as well as a cracking and separation of the grout from the flooring components (tiles, wood, marble slabs, etc.).

In some instances, attempts have been made to correct for the problems inherent with conventional grout approaches by incorporating in the modular flooring assembly a grout member or component that replaces or supplements traditional fill-in grout. While the concept of a grout member that can be inserted as a unit (and presumably removed if desired) is not new, existing solutions do not adequately address such problems as: securing the grout member between flooring components; centering the grout member; and accounting, via the grout member, for the inevitable variances in gap widths that exist between two or more assembled flooring components. Fox example, in U.S. patent application Ser. No. 10/752,591 to Pepa, “Paving System for Floor Tiles” (herein after “Pepa”), a number of various grout member solutions are disclosed. In each instance, the problems identified above are not resolved. More specifically, while Pepa discloses a grout member that may be inserted in the gap between tiles, assembly often requires the grout be inserted into a slot that is integral to one of two intersecting flooring components lying the grout to the flooring component in this manner invariably results in movement of the grout. The grout moves as the flooring component moves, and prevents the grout from being properly centered between tiles. Further, the solutions proposed in Pepa and others do not adequately account for variances in gap widths between adjoining components/tiles. Stated differently, existing grout systems are typically singular in size (width), and cannot easily or securely fit into gaps of varying width. While the grout solutions of the prior art may be slightly compressed and “stuffed” into a gap which would otherwise be too small, this “stop gap” approach does not address expansion and contraction depending on the gap width.

Other grout solutions, that do not necessarily tie the grout member to a flooring component, still fall short of expectations and needs. Certain prior art systems have “sealing lips” or “beads” to help prevent the leakage of moisture and/or adhesives into the flooring substrate. These designs, however, do not provide adequate flexibility and expansion/compression to allow for gap width variations. Therefore moisture contamination and unwanted adhesion are still a possibility Likewise, current systems do not provide a reliable means to secure the grout member in the gap through spring-like or functional forces.

As such, there is a need for a flexible, removable grout member that overcomes the limitations outlined above

SUMMARY

The methods and systems herein disclosed advance the art and overcome problems articulated above by providing a modular grout member that is sufficiently flexible yet sturdy; a grout member that can easily fit into gaps of varying widths while remaining centered to present an attractive and functional interstitial seal.

In particular, and by way of example only, according to an embodiment, provided is a grout member, including: a core having a horizontal strut interconnecting a first vertical support and a second vertical support; a surface section interfaced with the horizontal strut; a first flange extending outward from the first vertical support; and a second flange extending outward from the second vertical support, wherein the first flange and the second flange each interface with a corresponding modular flooring component to secure the grout member in position.

In yet another embodiment, provided is a grout member, including: a wedge shaped core having a horizontal strut interconnecting a first vertical support and a second vertical support; a surface section interfaced with the horizontal strut; a first malleable, resiliently deformable flange extending outward from the first vertical support; and a second malleable, resiliently deformable flange extending outward from the second vertical support, wherein each of the core, the malleable, resiliently deformable flanges, and the surface section ate formed from a different material.

In still yet another embodiment, provided is a method of sealing, with removable grout, a modular floor assembly, including: determining a pattern of required extended and truncated, removable grout members; cutting each removable grout member according to the pattern; inserting, in a first gap formed by at least four modular floor components, an extended, removable grout member; inserting, in a second gap formed by the at least four modular floor components, a first truncated, removable grout member; inserting in the second gap a second truncated, removable grout member; and verifying a press fit of each inserted extended and truncated, removable grout member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a grout member, according to an embodiment;

FIG. 2 is a cross-sectional view of a grout member, according to an embodiment;

FIG. 3 is a cross-sectional view of a grout member positioned between modular flooring components, according to an embodiment.

FIG. 4 is a cross-sectional view of a grout member positioned between modular flooring components, according to an embodiment;

FIG. 5 is a cross-sectional view of a grout member having extended flaps, positioned between modular flooring components, according to an embodiment;

FIG. 6 is a cross-sectional view of a grout member having extended flaps, positioned between modular flooring components, according to an embodiment;

FIG. 7 is a cross-sectional view of a grout member having flanges positioned at a base of a each vertical support, according to an embodiment;

FIG. 8 is a cross-sectional view of a grout member positioned between modular flooring components, according to an embodiment;

FIG. 9 is a perspective view of a grout member positioned between modular flooring components, according to an embodiment; and

FIG. 10 is a perspective view of modular flooring components integrated with grout members, according to an embodiment.

DETAILED DESCRIPTION

The present disclosure relates to a grout member or assembly for a modular floor/modular flooring assembly. The grout member is intended to fit or be installed between two adjacent floor assembly components, such as a tile, tray, frame, etc. During the installation process, the grout member is pressed into a channel between interconnected modular flooring assemblies. After installation, the grout member resembles traditional fill-in grout that is spread into the grooves between adjacent tiles. The grout member is positioned such that side members or flanges extend from a core to contact a surface of the corresponding floor assembly component The grout member may be filly formed during fabrication, may be manufactured from one or more materials, and is supplied to consumers ready for installation.

Of note, as detailed in U.S. patent application Ser. No. 11/432,873, the modular flooring assembly may comprise a tray substrate and a floor component. The floor component may comprise tile, stone, marble, wood, or other conventional flooring materials. The floor component could be a ceramic or porcelain tile, a natural stone product like marble or granite, or could be a wooden product. In at least one embodiment, floor tile systems may also incorporate the modular grout member disclosed herein. Each tray substrate typically includes connecting members, such as tabs, which allow tray substrates to interlock using tabs from two adjacent trays. The fully assembled modular floor, complete with the grout member of the present application, provides the appearance of a conventional floor.

Importantly, the modular floor may be assembled by individuals, who may lack the training and expertise to install a conventional floor. Also, the modular floor may be quickly disassembled without damaging the sub floor; as the grout member and the modular floor are not typically attached to the sub floor by adhesives, grout compounds, or other fastening means. Further, the grout member and the modular floor may be installed over an existing sub floor without the installation of a concrete backer board, which is commonly used in ceramic tile installation.

The present invention, using a grout member that is not permanently integrated with a tray or tile, offers certain advantages in assembly and disassembly. Further, the consumer may choose from among many different colored grout members. A damaged grout member may be easily replaced, and the grout member may also be changed to reflect different decorating tastes.

The modular flooring assemblies associated with the present invention may be in any number of sizes and shapes well known in the art, to include 6-inch, 6½-inch, 12-inch, 13-inch and 18-inch embodiments. They may have a square or rectangular shape. Further, combinations of flooring assemblies/tiles may be used, such as the 6-inch and 12-inch modular flooring assemblies, to provide a unique appearance. The present invention may be modified to compliment these combinations of different sized modular flooring assemblies. For each design of flooring assembly, the grout member of the present disclosure may be tailored in length to precisely align with the floor components.

Referring now to FIGS. 1 and 2, a perspective and a cross-sectional view of a grout member are presented. As shown in the figures, the grout member 100 may include a substantially horizontal section or strut 102 which interfaces with and joins two substantially vertical supports, 104 and 106 respectively. The vertical supports 104, 106 may intersect the horizontal strut 102 at any angle desired, typically at an angle in the range of 45° to 90° (i.e. normal to the horizontal strut 102.). In at least one embodiment of the present application, as represented in FIGS. 1 and 2, the angle formed by the vertical supports 104, 106 and the horizontal strut 102 is much closer to 90° than to 45°, on the order of 75°-85°.

Collectively, horizontal strut 102, and vertical supports 104, 106 comprise the core 108 of grout member 100. As shown, core 108 may have a “wedge-shaped” design that assists in holding grout member 100 in place between the tray substrates, tiles, or modular flooring assemblies. In particular, as the grout member 100 is installed between modular flooring components or assemblies, the “wedge” formed by the two vertical supports 104, 106 is compressed. This compression and the resulting opposite force supplied by the “wedge” assists in stabilizing and retaining the grout member 100 subsequent to its installation between the tray substrates, tiles, etc. The core 108 is generally formed as the hardest portion of the grout member 100. For example, in one embodiment a polypropylene may be used to form the core 108.

A surface section 110 is positioned atop of the core 108. More specifically, surface section 110 interfaces with and is secured to horizontal strut 102. In one embodiment, surface section 110 may be formed on the core 108 during an extrusion process. When an individual is standing on a modular floor incorporating grout member 100, and the member 100 is fully installed into a tray substrate or a modular floor, surface section 110 is the visible portion of the member 100.

The surface section 110 may be manufactured from a polypropylene thermal elastomer (TPE) such as SANTOPRENE®. In one or more embodiments, the elastomer of surface section 110 may contain a glass filled. The glass content may be approximately 3 percent to approximately 10 percent. The glass filler simulates the feel and appearance of a sanded grout, which is a desirable cosmetic feature. The glass filler further assists in stabilizing the temperature changes in the surface section 110 elastomer, which is an important functional feature since it reduces the expansion and contraction of the elastomer due to temperature fluctuations. Further, the elastomer may be manufactured in a variety of colors, and integrated with a variety of glass fillers, to match consumer choices in decorating.

In at least one embodiment, the surface section 110 may be made from a thermal plastic rubber or other resiliently deformable, compressible, pliable, malleable sealing material designed to fit between the tiles or tray substrates. The surface section 110 may include fluted edges 112 and 114 that seal against a tile and assist the grout member 100 in providing the finished appearance of conventional fill-in grout.

Still referring to FIGS. 1 and 2, flanges 116 and 118 extend generally outward from each vertical support 104, 106, respectively. As shown in FIG. 2, flange 116 extends outward from vertical support 104. Similarly, flange 118 extends outward from vertical support 106. The flanges 116, 118 may generally taper in width towards a tip, 120 and 122 respectively. However, it can be appreciated that the present application also anticipates and discloses an extended flange or flanges that are not tapered, such as those depicted in FIG. 7 (flanges 700 and 702). As illustrated in greater detail in FIG. 2, the flanges 116, 118 form an angle “α” in the range of approximately 30° to approximately 70° relative to the vertical supports 104, 106, when uninstalled. As discussed in greater detail below, the flanges 116, 118 are formed of a malleable, resiliently deformable material and may bend and flex, thereby reducing the angle “α” and, in this manner, assist in holding the grout member 100 in position.

The grout member 100, which includes the surface section 110, core 108, and flanges 116, 118, may be formed from co-extrusion processes. Each of the core 108, the surface section 110, and the flanges 116, 118 may be co-extruded using three different materials exhibiting physical properties directed to the particular function of each element or component. For example, as represented in FIG. 2, the core 108 may be formed from a first material 124, the flanges 116, 118 may be formed from a second material 126, and the surface section 110 may be formed from a third material, 128. The first material 124 forming the core 108 may be harder than the second 126 and third 128 materials, as the core 108 forms a supporting structure. The co-extrusion process reduces manufacturing costs and provides a uniform product.

In at least one embodiment of the present disclosure, grout member 100 forms a generally straight structure with a generally uniform cross-section throughout its entire length. The grout member 100 may be produced in any length practical and economical; however, standard lengths may include 8 foot lengths and 12 inch lengths, which are suitable for installing with 12 inch by 12 inch tiles. Since 8 foot lengths may be utilized, installation time is reduced as many of the grout lines in a first direction may be installed with the 8 foot lengths of the grout member 100, while the 12 inch lengths may be installed in a second, opposite direction. As there are fewer pieces to install as compared to other embodiments, installation labor times may be reduced.

The grout member 100 may be used with any size tile. Generally, as noted above, grout member 100 will be supplied to the customer in two lengths, an extended length, such as several feet to approximately 8 to 12 feet, and a second, truncated, length generally corresponding to the length of the tile, which may be 6-inch, 12-inch, 13-inch, 18 inch, etc. By using grout members 100 with the extended lengths, the finished modular floor will have less grout seams (points where two sections of grout intersect) and installation is easier, since there are less extruded grout sections to install. The extended lengths of grout member 100 may also be easily cut to fit with snips, heavy shears, or a light saw.

Referring now to FIGS. 3 and 4, a unique feature of the present disclosure is highlighted As noted above, flanges 116, 118 may bend and flex, thus creating a “spring action” to assist in positioning and holding the grout member 100 between two components of a modular floor (tray, flame, tile, etc.). The mechanical consequences of this element of the invention are that differences or discrepancies in the gap between modular floor components can be accommodated and accounted for while still providing a finished grout look and seal. More specifically, if the gap “b” (FIG. 4) between two trays 400, 402 and tiles 404,406 is smaller than gap “a” (FIG. 3) between similar trays 300, 302, and tiles 304, 306 in a given modular floor assembly, flanges 116 and 118 may bend and flex (in the case of gap b”), or fully extend (in the case of gap “a”), thereby allowing the grout member 100 to be securely centered in each instance. Concurrently, the surface section 110 may be compressed as well to fit within the gap presented. Stated differently, grout member 100 can account, in large part, for the mechanical tolerances that inevitably build-up during the assembly, of any modular system, despite the best designs and manufacturing techniques. By virtue of “flexible” flanges and not being tied to one Or the other modular components (e g. 300, 302, 400 or 402), grout member 100 is free to “float” and always remain centered in position. Of note, this same “flex and bend” capability of flanges 116, 118 helps to ensure that a tight press fit is achieved between grout member 100 and the two modular floor components, even if the floor component surfaces with which grout member 100 interfaces are not truly parallel; and (b) a greater surface area of the flange, e.g., flange 116, contacts a surface of the modular floor assembly, e.g. tray 400, thereby providing greater frictional (mechanical) forces to hold the grout member 100 in place.

Importantly, grout member 100 provides several sealing surfaces to seal the grout-modular floor assembly and prevent moisture or fluids from entering the tray substrate or the modular floor. As can be appreciated by referring, for example, to FIGS. 3 and 5, the surface section 110 FIG. 3) or 500 (FIG. 5) may form a seal pressing against the tile, e.g. tile 304 in FIG. 3 and tile 502 in FIG. 57 to form a moisture, adhesive, and dust barrier. Likewise the flange combinations (e.g. 116 and 118 in FIG. 3/506 and 508 in FIG. 5) also form a seal by pressing against a tile or tray, e.g. tray 510 in FIG. 5.

Referring now to FIGS. 5 and 6, an alternate embodiment of the present disclosure is depicted, wherein the surface section 500 may include extended flaps (512, 514) on either side of the surface section 500. As shown, if the gap between modular floor components, e.g. trays 510 and 516, is sufficiently wide, the extended flaps 512, 514 will meet flush with the edge of the tile 502 or 518. If, however, as shown in FIG. 6 the gap varies and is occasionally somewhat smaller than typically encountered, as if often the case with modular floors, the extended flaps 512, 514 may extend over the top surfaces 520, 522 of the tiles 502, 518, thereby adequately sealing the gap while providing a finished look to the entire grout—floor assembly.

Referring once again briefly to FIG. 7, yet another embodiment of the present disclosure is presented. As shown, flanges 700 and 702 are positioned lower relative to the length of the vertical supports, 704 and 706 respectively, and the position of the surface section 708. Stated differently, flange 700 extends outward from a base of support 704 while flange 702 similarly extends outward from a base of support 706. As such, the flanges 700 and 702 may be somewhat longer in length than those shown in the other embodiments. The advantage to this embodiment is that greater flexibility may be designed into the flanges 700, 702, which in turn typically yields a greater flange-to-modular floor interlace surface when the grout member 710 is placed into position, similar to FIGS. 4 and 6.

In FIG. 8, a grout member 800 is fully installed into the gap or channel 802 formed when two modular floor assemblies, e.g. assemblies 804 and 806, are interlocked. As shown in FIG. 8, the interlocking tabs 808 and 810 form a strong, semirigid base upon which the bottom tips 812, 814 of vertical supports 816, 818 press down. This positioning provides a stabilizing foundation for the grout member 800. The foundation provided by the core 820 and the two vertical supports 816, 818 pressing on the base formed by the tabs 808, 810, withstands the substantial weight of individuals walking on the fully assembled modular floor, as well as the weight of furniture, appliances, etc. By supporting the core 820 and the vertical supports 816, 818, in the manner depicted in FIG. 8, the grout member 800 has a solid feel that does not feel spongy or soft to the touch, i.e., the grout member 800 feels similar to a traditional fill-in grout product. The two vertical supports 816, 818 provide a firm pedestal for the grout member 800 and assist in securing the position of the grout member 800. In at least one embodiment, as shown in FIG, 8 and elsewhere, the core 820 has a hollow region between the two vertical supports 816, 818. The practical result of combining a semi-hollow core with well supported vertical supports is a reduced material cost while maintaining strength and structural integrity.

Considering for a moment FIG. 9, yet another implementation of the present disclosure is presented. In many instances, the tile or other flooring used in a modular floor design may be beveled. For example, in FIG. 9, tile 900 has a beveled edge 902 oriented and sloping generally toward the grout member 904. In this instance, the top of grout member 904 may not be positioned flush with the top surface of the tile 900, but may instead lest lower within the gap 906. Nonetheless, the surface section 908 of member 904 fits flush against the tile 900 side surface, providing the necessary seal between flooring and grout. In at least one embodiment employing a beveled tile design, fill-in grout of the type well known in the art may be placed above the surface section 908 to fully close out the gap 906. When fill-in grout is employed, grout member 904 serves to properly maintain the size and integrity of the gap 906, support the hardened fill-in grout, and minimize the amount of fill-in grout required to fill the gap 906.

Referring now to FIG. 10, a modular floor assembly 1000, including interconnected modular flooring trays 1002, 1004, 1006 and 1008 is disclosed. The trays may be any tray or frame-type device used to secure flooring materials, to include the frames with tabs disclosed and claimed in U.S. patent application Ser. No. 11/432,873 filed May 12, 2006. For simplicity sake, a single tile, 1010 is shown positioned within tray 1008, however, it can be appreciated that all four trays 1002-1008 would typically contain a tile or other flooring component (wood, marble, etc.). For exemplary purposes, a single, extended grout member 1012 and two truncated grout members 1014 ate 1016 are shown installed in a finished position. After the modular flooring assemblies (trays) are interconnected, a pattern is established and the required grout lengths defined. Accordingly, grout members (e.g. member 1012) are cut to length. A grout member (e.g. 1012) is installed by pressing the grout member in the gap between the modular flooring assemblies. No special tools are required. Extended and truncated grout members (e.g. 1012 and 1014) are installed in a repeating pattern until the entire floor assembly is grouted. A grout member of the present application is a fabricated structure that does not undergo a drying process or phase change during its installation. Unlike a traditional fill-in grout, the grout member is not a paste or compound that is spread between the modular flooring components, therefore installation and clean up are simplified.

As the grout members, e.g. member 1012, are installed between modular flooring components, the flanges, e.g. flange 116 in FIG. 2 and 1018 in FIG. 10, are forced upward, thus providing a spinning-action to hold the grout member e.g. member 1012 in position. Importantly, in at least one embodiment as discussed above, the flanges (e.g. flange 1018) are pushing outward against an edge of the flooring component (e.g. tray 1008) while the wedge shape formed by the two vertical supports, e.g. support 1020, is pressing on a top surface of tabs attached to the trays 1002-1008. This action of anchoring the grout member 1012 against these two different surfaces, namely the edge of tray 1008 and the tabs attached thereon (not shown), provides for the secure installation of the grout member, e.g. member 1012 At the completion of the installation, the press fit of all grout members is verified. Despite the wedge action, the grout member 1012 may be removed from the modular floor after it is installed by a firm pulling action.

The flanges, e g, flange 1018, preferably extend the entire length of the grout member 1012, although a grout member with an intermittent ox discontinuous flange may also be used. The dimensions of certain embodiments of an extruded grout member (e.g. 1012, 1014, 1016) may include: (a) a surface section having a thickness of approximately 0.05 inches to approximately 0.09 inches and a width of approximately 0.2 inches to approximately 0.3 inches; (b) a core, including the two vertical supports, having a thickness of approximately 0.02 inches to approximately 0.05 inches; and (c) flanges having a width of approximately 0.1 inches to approximately 0.3 inches. These dimensions described are suitable for many applications of modular flooring; however, the dimensions may be altered by one of ordinary skill in the art practicing the invention as required for their particular tiling application.

Changes may be made in the above methods, devices and structures without departing from the scope hereof. It should thus be noted that the matter contained in the above description and/or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to cover all generic and specific features described herein, as well as all statements of the scope of the present method, device and structure, which, as a matter of language, might be said to fall therebetween.

Claims

1. A grout member, comprising:

a core having a horizontal strut interconnecting a first vertical support and a second vertical support;

a surface section interfaced with the horizontal strut;

a first flange extending outward from the first vertical support; and

a second flange extending outward from the second vertical support

wherein the first flange and the second flange each interface with a corresponding modular flooring component to secure the grout member in position.

2. The grout member of claim 1, wherein the first flange and the second flange are resiliently deformable.

3. The grout member of claim 1, wherein the surface section is a polypropylene thermal elastomer.

4. The grout member of claim 3, wherein the surface section is a polypropylene thermal elastomer having a glass content in the range of 3 to 10 percent.

5. The grout member of claim 1, wherein the core is a first material, the first and the second flanges are a second material, and the surface section is a third material.

6. The grout member of claim 5, wherein the hardness of the core material is greater than the hardness of the flange material and the surface section material.

7. The grout member of claim 1, wherein the first flange extends outward from a base of the first vertical support, and further wherein the second flange extends outward from a base of the second vertical support.

8. The grout member of claim 1, wherein the surface section comprises:

a first extended flap; and

a second extended flap.

9. The grout member of claim 1, wherein the first flange and the second flange extend continuously along an entire length of the grout member.

10. The grout member of claim 1, wherein the first flange and the second flange are discontinuous.

11. The grout member of claim 1, wherein the member is extruded.

12. The grout member of claim 1, wherein the first flange and the second flange are tapered.

13. A grout member, comprising:

a wedge shaped core having a horizontal strut interconnecting a first vertical support and a second vertical support;

a surface section interfaced with the horizontal shut;

a first resiliently deformable flange extending outward from the first vertical support; and

a second resiliently deformable flange extending outward from the second vertical support

wherein each of the core, the resiliently deformable flanges, and the surface section are formed from a different material.

14. The grout of claim 13, wherein the core is made of a first material that is harder than both a second material forming the flanges and a third material forming the surface section.

15. A method of'sealing, with removable grout, a modular floor assembly, comprising:

determining a pattern of required extended and truncated, removable grout members;

cutting each removable grout member according to the pattern;

inserting, in a first gap formed by at least four modular floor components, an extended, removable grout member;

inserting, in a second gap formed by the at least four modular floor components, a first truncated, removable grout member;

inserting in the second gap a second truncated, removable grout member; and

verifying a press fit of each inserted extended and truncated, removable grout member.

16. The method of claim 15, wherein the pattern of one extended and two truncated removable grout members repeats.

17. The method of claim 15, wherein a surface section of each of the extended and truncated grout members is a polypropylene thermal elastomer.

18. The method of claim 17, wherein the surface section of each of the extended and truncated grout members is a polypropylene thermal elastomer having a glass content in the range of 3 to 10 percent.

19. The method of claim 15, wherein a core of each grout member is a first material, a first and a second flange of each grout member is a second material, and a surface section of each grout member is a third material.

20. The method of claim 19, wherein the hardness of the core material is greater than the hardness of the flange material and the surface section material.