US20040205890A1

US20040205890A1 - Floor drainage construction

Info

Publication number: US20040205890A1
Application number: US10/637,273
Authority: US
Inventors: Gregory Smale
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-08-08
Filing date: 2003-08-08
Publication date: 2004-10-21
Also published as: AU2003231697A1

Abstract

A drainage surface construction is provided for a bathroom or shower floor. The surface is formed using a rigid polyurethane foam support that is contoured or sloped to facilitate drainage toward a drainage point. In one embodiment the support is cut to size to align with a drainage area and drainage outlet. A sill is provided about a peripheral edge of the support and a sill cover can be laid over the sill to assist with tiling, location of bathroom joinery and aesthetic appearance.

Description

FIELD OF THE INVENTION

This invention relates to a method, apparatus and kit of parts for constructing a surface or a floor for drainage. The invention has particular application to drainage surfaces for floors for bathroom installations such as bathroom or shower floors.

BACKGROUND OF THE INVENTION

Stand-alone shower installations are becoming increasingly popular. These necessitate a sloped floor to provide a drainage surface that allows water to drain to a drainage outlet. Similarly, there is also a demand for bathroom floors that have a drainage surface that provides a slope to a drainage outlet.

The conventional method of forming a draining floor construction is to firstly form a solid base using a substance such as plaster or cement. The substance used is contoured using a trowel for example to provide a desired slope from the peripheral edges of the base to a drain entry so that the resultant floor drains properly. The base is then left to harden, which may take several days. The hardened base is then usually sealed, for example using a sealant coating and/or a material that forms a waterproof membrane over the base to the drain. Finally, the base is usually tiled.

As an alternative to using a substance such as plaster or cement, a pre-formed base may be used. Such bases may then be sealed and tiled. Preformed bases that are provided as a single unit are made to various standard sizes.

These floor constructions and construction methods present a number of problems. Even if a pre-formed base is used, there is often a problem obtaining a base of the necessary size for a desired floor outline, and providing the drainage outlet in the required position to fit the drain in the underlying floor.

Another problem with existing constructions is providing an aesthetically pleasing appearance, particularly the interface between the floor and the surrounding area. The edges of a tiled floor can also present problems with regard to water leaks. Therefore, in existing constructions, tile layers need to be very careful to provide tiles which are carefully cut to meet the edge of the floor adjacent to the doors and some walls. Generally speaking, the edges of the floor which are bounded by structural walls do not present a significant problem since a waterproof membrane can be applied up to the base of the walls. Then the floor tiles can simply be placed so as to abut the wall and then grouted or otherwise sealed in the usual way. However, the edges and the floor surfaces that are not bounded by structural walls are typically raised in relation to the remainder of the floor. This is because a slope is required between the peripheral edges of the floor and the drainage point on the floor in order to ensure that water drains properly to the outlet. If the peripheral edges that are not bounded by structural walls are to be level with a remaining floor surface such as that surrounding a shower for example, then the shower floor as a whole needs to be recessed. Either way, there are problems with the interface between the peripheral edges of the floor that are not bounded by structural walls.

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

OBJECT OF THE INVENTION

It is an object of the present invention to provide a method, apparatus or kit of parts for constructing a surface or floor for drainage which will at least go some way toward overcoming one or more of the disadvantages of existing constructions or methods. Alternatively, it is an object of the invention to at least provide the public with a useful alternative.

SUMMARY OF THE INVENTION

In a first aspect the invention provides a method of constructing a drainage surface for a drainage area having a defined drainage outlet point, the method including

defining the drainage area,

defining the drainage outlet point within the drainage area,

providing a substantially planar unitary rigid support member including one substantially flat surface and an opposite drainage surface forming a slope from an outer region at which the support member is thicker to a central region at which the support member is thinner, and a support drainage point within the central region,

cutting or shaping the outer region so that the support member is substantially coterminus with the defined drainage area and so that the support drainage point is substantially coincident with the drainage outlet point,

positioning the support member in the drainage area to provide the drainage surface, and forming a seal over the support member.

In a further aspect the invention provides a kit of parts for constructing a floor drainage installation, the kit of parts including

a sill for provision along a peripheral edge of a floor support member to provide a peripheral floor edge that protrudes above the support member, and an elongate edge cover of a substantially rigid material having one or more walls adapted to fit about the peripheral floor edge and substantially cover the edge.

In a further aspect the invention provides a method of constructing a shower floor, the method including the steps of providing a floor support member having a contoured surface to facilitate drainage to a selected drainage point, providing a sill at a peripheral edge of the support member to provide a peripheral floor edge that protrudes above the base, and covering the peripheral floor edge with an elongate substantially rigid edge cover.

In a further aspect the invention provides a floor installation including a floor support member having a contoured surface to facilitate drainage to a selected drainage point, a sill provided at a peripheral edge of the support member to provide a peripheral floor edge that protrudes above the support member, and an elongate edge cover of a substantially rigid material having one or more walls provided about the peripheral floor edge to substantially cover the edge.

In a further aspect the invention provides a support member having a substantially flat first surface, a second surface opposite the first surface the second surface being contoured to facilitate drainage to a selected drainage point, and being constructed from a rigid foam material and having an integral sill provided along at least one peripheral edge of the second surface, the sill protruding from the second surface.

In a further aspect the invention provides a tile floor underlay having a substantially planar upper surface and a substantially planar lower surface and at least one substantially vertical peripheral edge, and

a sill member adapted to be attached to the peripheral edge, the sill member having an upper edge which, when attached to the peripheral edge, protrudes beyond the upper planar surface of the underlay.

In a further aspect the invention provides a tile floor construction assembly including

a sill member to provide a peripheral edge for the floor, and

an elongate edge cover having a body with a first locating portion and a second location portion,

the first locating portion adapted to be disposed upon an upper edge of the sill member in use, and

the second locating portion adapted to in use rest upon the shower tile floor surface.

In a further aspect the invention provides a tile floor sill comprising a foot member for location on a floor surface beneath or external to the shower tile floor, and a wall member dependent from the foot member and provided substantially perpendicular to the foot member, the wall member in use defining an edge of the shower tile floor.

In a further aspect the invention provides a tile floor edge cover having an elongate body with a first locating portion and a second locating portion,

the first locating portion adapted to be disposed upon an upper surface of the edge, and

the second location portion adapted to rest in use upon the shower tile floor surface.

In a further aspect the invention provides a method of providing a shower tile floor underlay, the method comprising the steps of

laying one or more sill members which define a peripheral edge of the underlay, and

providing a tile underlay in the shower floor space which is at least partially bounded by the one or more sill members.

DRAWING DESCRIPTION

The invention consists of the foregoing and also envisages constructions of which the following gives examples only. [0034]
One presently preferred embodiment of the invention will now be described with reference to the accompanying drawings, wherein; [0035]
FIG. 1 is a perspective view of a support member for a drainage surface such as a shower or bathroom floor, [0036]
Figures [0037] 1A-1E are diagrammatic plan views of various shower floor layouts,
FIG. 2 is a partial elevation in cross section of an underlay such as that shown in FIG. 1 including a tiled surface thereon, and a peripheral sill, [0038]
FIG. 3 is an end elevation of an edge cover, [0039]
FIG. 4 is a further partial elevation in cross section showing a combination of the constructions shown in FIGS. 2 and 3, [0040]
FIG. 5 is another side elevation in cross section of the general construction of FIG. 4, but also including a structure support member, [0041]
FIG. 6 is a further side elevation in cross section of the construction of FIG. 5, but with the structure support extrusion provided in an alternative location, [0042]
FIG. 7 is a further side elevation in cross section showing an alternative form of support, [0043]
FIG. 8 is a perspective view of an alternative embodiment of a support member for a drainage surface such as a shower or bathroom floor, [0044]
FIG. 9 is a partial side elevation in cross section of the support of FIG. 8 including an edge cover, [0045]
FIG. 10 is a diagrammatic plan view of a possible drainage area such as a shower or bathroom floor requiring a drainage surface, [0046]
FIG. 11 is a diagrammatic plan view of an alternative embodiment of a support for a drainage surface, and which may be used to accommodate the drainage surface of FIG. 10, and [0047]
FIG. 12 is a diagrammatic perspective view of the support of FIG. 11 together with sill members for abutting edges of the support.[0048]

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIG. 1, an example of a support member or base for a floor is shown generally referenced [0049] 1. Although the shape represented in the drawing is substantially square, it will be seen to those skilled in the art that many other shapes may be used. The panel has a drainage point 2 which is usually provided as an aperture, or as a relatively thin section which may be easily removed (for example by being cut out) by a user. It has an even slope between approximately 1.5° and 3°, preferably 2°, between the drainage point and the outer peripheral edge of the panel or panels.
A full description of a system which uses multiple panels in order to construct a base which has a constant slope for drainage purposes, and which is suitable for tiling over, is described in our co-pending application number NZ 510443. [0050]
The invention described with reference to FIGS. 2-7 in this document is applicable to a range of drainage surface constructions including: [0051]
(a) the system described in our co-pending application NZ 510443; [0052]
(b) unitary support members or panels which are specifically moulded or otherwise formed to various drainage surface shapes, and [0053]
(c) traditional or known support constructions such as a sand and cement mixture, or plaster, contoured to facilitate drainage. [0054]
Examples of some drainage areas, in this case shower floor shapes, are shown in FIGS. [0055] 1a-d. In these Figures, the heavy lines represent permanent wall surfaces, such as structural wall surfaces which may be tiled for example. The light lines represent non- structural wall surfaces, for example glass walls, plastic walls or doors.
As described in our co-pending application, the preferred material from which the support panel or panels represented in FIG. 1 is constructed is a substantially rigid material, and is most preferably a strong polyurethane structural foam. This foam is compatible with waterproof membranes, and since it is not easily compressed, is ideal for providing a drainage surface which may be tiled over. We have found that a polyurethane foam material having a density from about 80 to about 200 kilograms of chemical per cubic meter of final product provides best results. Most preferably, the foam material has about 100 kilograms of chemical per cubic meter of final product and may generally consist of a mixture of polyol/isocyanate. Such polyurethane foam may be purchased commercially from Bayer. The panel or panels may be moulded for example or cut to provide the required shape. Moulding may be performed using a metal die into which foam is injected under pressure. Cutting may be performed using an appropriate cutting tool such as a saw. [0056]
One example of the invention is shown in FIG. 2 in which a [0057] sill 6 is attached to one of the peripheral edges 4 of a support member in the form of panel 1. The sill 6 is preferably an extrusion such as an aluminium extrusion, but other materials such as a plastic material for example could be used. The panel 1 has a tile 8 thereon. Grout 7, or another suitable compound, may be provided between the sill 6 and the tile 8. Between the panel and the tile is a seal in the form of a membrane 10, which is substantially waterproof. In this way, any water that manages to seep past the tile 8 falls onto the membrane from which it is transported from the membrane to the drain aperture 2. The sill 6 provides a suitable edge against which the tiles may be placed. Therefore, it assists with the tiling process and also provides a water barrier.
To assist with the attachment of the [0058] sill 6 to edge 4, a foot 12 can be provided on the sill. This provides additional surface area for making the attachment. The preferred method of attachment is glue, but suitable fasteners may also be used. The upper edge 9 of sill 6 protrudes above the upper surface of the underlay panel 1. The upper protruding edge 9 is preferably used to support an elongate member as will be described further below. It will be seen that the edge 9 has an inwardly directed flange 14 followed by a substantially vertically projecting rim 16.
In FIG. 3, an elongate member, which preferably comprises an edge cover member in the form of a metallic extrusion (preferably aluminium), is shown in cross section, generally referenced [0059] 20. Member 20 has a first receiving portion 22 and a second receiving portion 24 both provided from a main body 26 that also includes a depression 28. The receiving portions 22 and 24 conveniently have ridges or teeth 25 and 27 respectively, for retention purposes as will be described further below.
In FIG. 5, the [0060] member 20 is shown in use with the panel and wall assembly of FIG. 2. The first receiving portion 22 is located about the rim 16. A resilient material, such as a plastics or rubber material 30 assists with retention to provide frictional engagement between the two members.
The other receiving portion [0061] 24 includes another suitably resilient material such as a firm plastics material 32 which is retained by the ridges on the inner side surfaces of the retention portion. As can be seen from the drawing, member 32 provides a leg that is of a suitable dimension so that the central body portion 26 is substantially horizontal i.e. generally parallel to the floor surface relative to which the shower base is provided.
This construction has significant advantages. Firstly, it provides a region which protrudes over the edge of the tile or other finished surface, so the outer edge of the tile is not visible to a shower user. Therefore, the tile layer does not have to spend as much time profiling or organising each tile to provide a desired aesthetic appearance. Accordingly, the assembly has the advantage of allowing a certain amount of tolerance in fitting tiles. Also, the assembly provides a certain amount of physical protection about the edge of the tiled surface. For example, a user can step on the surface without damage (such as a cut) to the user's foot. [0062]
It will be seen that the [0063] elongate member 20 may be provided in a number of different physical forms while still achieving the purposes set forth above. To cover an angled peripheral edge, the member 20 needs to incorporate one or more corners of some form. Such corners could be formed as part of the manufacturing process. However, to reduce cost, and allow a number of different peripheral edge contours to be achieved brackets 60 are provided. These may consist of simply flat pieces of a suitable material such as aluminium that incorporate an angle of the necessary dimension dependent on the peripheral edge contour, e.g. 90° or 120°. The points at which the brackets are provided in FIGS. 1A-1C are shown by arrows 62. The brackets 50 are attached to the elongate members 20 using fasteners such as screws or rivets, or by gluing, for example. Alternatively, if the fit between the member 20 and the bracket is sufficiently tight, frictional engagement may be sufficient.
Yet another advantage is achieved by placing a wall support member, generally referenced [0064] 40, over member 20. This wall support member can be anchored at certain points, using fasteners for example, and can be used to support a vertical member, such as a glass wall 42, or a pillar or a solid wall or shower door for example. As can be seen, the base assembly 40 is preferably constructed from two separate components. This assists with location about the bottom edge of the wall 42.
Advantageously, the [0065] depression 28 in member 20 provides a water or liquid which runs down wall 42, and which is not splashed or otherwise directed inwardly toward the drainage surface, will tend to run down the surfaces of assembly 40 and be captured in depression 28. Although not shown in the drawings, depression 28 has one or more small holes therein through which water can pass, and from there follow the tile outer surface, or follow the membrane 10 down the slope to the drain.
In FIG. 6, the same assembly as that of FIG. 5 is again shown, but with the [0066] assembly 40 slightly changed in position so that the water trap provided by depression 28 is located externally of the assembly 40 rather than within that assembly.
In FIG. 7, another construction is shown which is identical to the constructions described above, except that the [0067] panel 1 has a step 50. This step allows the slope of surface 52 to be maintained substantially constant for edge surfaces 4 that are relatively close to the outlet drain. This is because edge surfaces that are close to the outlet drain may require a steep slope if a flat surface is provided between the edge and the drain. The step construction can overcome this problem as illustrated in FIG. 7.
In FIGS. 8 and 9, another example of the invention is shown. Like reference numerals denote like features between the constructions described above and the construction shown in FIGS. 8 and 9. [0068]
FIG. 8 shows a support member generally referenced [0069] 70 that has a drain 2 and sides 4. It also has a sill 72 incorporated in one of the edges to provide a protruding edge 9. Although only shown along one peripheral edge in the drawing, the sill could be included along other edges, or all the edges 4. The sill 72 is provided as an integral part of the support member which is preferably constructed from a compressed polyurethane foam material as described above. The underlay may be formed by moulding for example or by cutting to shape. The underlay may be provided as a unitary item as shown in FIG. 8, or be provided in a plurality of constituent parts as described above.
In FIG. 9 the support member of FIG. 8 is shown with an [0070] edge cover 74 to cover the protruding edge 9 of the sill. The cover is preferably provided as an extrusion, most preferably an aluminium extrusion. The cover has a central portion 76 that provides a clean finish to the edge of the base. It also provides a support or engagement surface for joinery such as a shower wall or door base 40 of FIGS. 5 and 6. Still referring to FIG. 9, the cover 74 has supports 78 that rest on edge 9 and assist with engagement which is preferably made by applying silicone to edge 9 before the cover is applied. A protruding portion 79 of the cover assists the aesthetic appearance of the installation by obscuring the outer edge 77 of tile 7.
[0071] Walls 80 of the cover extend over either side of the edge 9. They also have removable regions 82 and 84 that are defined by lines of weakness 86 which allow regions 82 and 84 to be removed using a tool such as pliers for example to break one or more of the weakened areas 86. Therefore, the height of the walls 80 is adjustable depending upon the height of the base. The walls 80 allow the cover to extend substantially all the way to the shower floor tile or other surface finish 7 and the exterior floor tile or other surface finish 88. Spaces between the base of walls 80 and the tiles 7 and 88 may be filed with a grout or similar material (not shown).
In use, an installer places the support member of FIG. 8 in the required location and applies a sealing membrane to the support member including the protruding edge(s) [0072] 9 provided by the integral sill(s). The cover member 74 is cut to the required length, then silicone or an appropriate bonding material is placed on the edge 9 and the cover is attached. If there are a number of edges, then the cover members may be mitred or similarly cut to provide a desired aesthetic appearance. Brackets 60 as described above may be placed in spaces between members 78 to secure the cover construction.
From the foregoing it will be seen that a construction is provided which has significant advantages. The advantageous include: aesthetic appearance; water drainage functions; greatly reducing cutting being required when fitting tiles (or other surface finishes); wall, pillar and/or door support functions, together with adding mechanical robustness to the overall construction. [0073]
It will be appreciated that the construction can be provided as separate components which may be assembled to create the desired end result i.e. the constructions may be provided as kits of parts with various combinations of components. Therefore, for example: either one or a number of separate underlay panels can be provided to create the desired floor underlay, the [0074] sills 6 can be provided as separate components which can be cut (if required) by a user to required lengths. The elongate edge cover members 20 and 74 can also be provided separately, as can the extruded base support assembly 40.
The [0075] sill 6, covers 20 or 74 and related components can also be used in conjunction with a support constructed from a sand and cement mixture (or any other substance that can be appropriately contoured by a user and which hardens to provide an appropriate floor tile underlay). For example, one or more sill members 6 may be arranged to define the periphery (or part of the periphery) of the required drainage area shape. Then a wet sand and cement mixture can be introduced into the area bounded by the sill member(s) and screeded or otherwise contoured to provide a desired drainage profile to direct water towards the waste outlet. The upper edges of the sill members may be used to assist with the screeding process, and ensure that a floor edge of uniform height is provided. The composition is allowed to harden, after which the tiles can be laid, and the edge cover member(s) 20 can be applied as described above.
Referring to FIGS. [0076] 10 to 12, a further method and construction will be described. FIG. 10 shows a possible drainage area generally referenced 100 having a drainage outlet 102 which is off-centre. Also, the boundary 104 of the drainage area 100 is longer than boundary 106. This form of drainage area is problematic since it does not conform to a standard layout, yet it is a layout which a user may require for a drainage area such as a bathroom or shower floor.
In FIG. 11 a support member is shown generally referenced [0077] 108. This is formed from a rigid material, preferably a polyurethane foam as described previously in this document. We have found that such material can be easily cut or shaped using a hand tool, for example a manual hand tool or power tool, but most preferably a knife or hand saw. The support 108 has a generally flat lower surface, but a sloped upper surface as described previously in this document, so that the upper surface provides a drainage surface to allow water to drain to from the relatively thicker peripheral region to a thinner central region in which the drainage point 110 is provided. As shown in the drawings, the support 108 may be larger in one or more dimensions than the drainage area 100.
In use, a user marks, observes, or otherwise defines the [0078] drainage outlet 102 and calculates the distance from the drainage outlet 102 to the boundaries of the drainage area 100, then cuts or shapes the support 108. In the example illustrated, the cuts that allow the support to accommodate the drainage area are shown by dashed lines 112, 114 and 116. When these cuts are made by the user the boundaries of the support are generally coterminus with those of the drainage area and the drainage point 110 is generally coincident with drainage outlet 102.
The final steps are to lay the [0079] support 108 over the drainage area 100, then seal the upper surfaces of the support if required, and lay the desired finishing surface such as tiles for example. The support is sufficiently rigid for a rigid cover layer such as a mortar bed or shower tray to be dispensed with.
Furthermore, a sill may be provided as an integral part of the base [0080] 108 in a similar fashion to that described above with reference to FIG. 8, or a sill may be provided as described earlier in this document. Also, as shown in FIG. 12, sill members 118 constructed from the same type of material as the support 108 may be placed so as to abut the edges of the support. The sill members 118 may be cut or shaped to accommodate any differences in height of the edges of the support after it has been cut and may be attached by gluing for example. Therefore a variety of different areas such as shower floors or bathroom floors may be effectively provided with a drainage surface.
This last embodiment of FIGS. [0081] 10 to 12 has the advantage that only a few sizes of support member need to be provided for use with multiple drainage areas, and unusually shaped drainage areas or those having a waste outlet in an unusual position may be easily accommodated.
Finally, those skilled in the art will realise that a number of variations or equivalents can be made without departing from the scope or spirit of the invention disclosed herein. [0082]
Throughout the description and claims of this specification the word “comprise” and variations of that word, such as “comprises” and “comprising”, are not intended to exclude other additives, components, integers or steps. [0083]

Claims

1. a method of constructing a drainage surface for a drainage area having a defined drainage outlet point, the method including

defining the drainage area,

defining the drainage outlet point within the drainage area,

positioning the support member in the drainage area to provide the drainage surface, and

forming a seal over the support member:

2. A method as claimed in claim 1 further including the step of tiling the drainage surface.

3. A method as claimed in claim 1 further including the step of providing one or more sill members abutting one or more peripheral edges of the support member

4. A method as claimed in claim 1 wherein the support member prior to cutting or shaping is larger in at least one dimension than the drainage area.

5. A method as claimed in claim 1 wherein the support member is made from a polyurethane foam material having a density from about 80 to about 200 kilograms of chemical per cubic meter of final product

6. A method as claimed in claim 1 wherein the drainage surface is a surface of a shower floor.

7. A method as claimed in claim 1 wherein the drainage surface is a surface of a bathroom floor.

8. A kit of parts for constructing a floor drainage installation, the kit of parts including a sill for provision along a peripheral edge of a floor support member to provide a peripheral floor edge that protrudes above the support member, and an elongate edge cover of a substantially rigid material having one or more walls adapted to fit about the peripheral floor edge and substantially cover the edge.

9. A kit of parts as claimed in claim 8 including the support member, and wherein the sill comprises a peripheral edge of the support member.

10. A kit of parts as claimed in claim 8 wherein the edge cover protrudes onto or over the floor.

11. A kit of parts as claimed in claim 10 wherein the edge cover includes a leg adapted to contact the shower floor.

12. A kit of parts as claimed in claim 8 wherein the edge cover includes two side walls, each side wall being adapted for location on one side of the edge.

13. A kit of parts as claimed in claim 12 wherein at least one of the walls has an area of weakness whereby a portion of the wall may be removed to allow adjustment of the height of the at least one wall.

14. A method of constructing a shower floor, the method including the steps of providing a floor support member having a contoured surface to facilitate drainage to a selected drainage point, providing a sill at a peripheral edge of the support member to provide a peripheral floor edge that protrudes above the base, and covering the peripheral floor edge with an elongate substantially rigid edge cover.

15. A method as claimed in claim 14 including the step of providing the support member as a floor underlay including the sill.

16. A method as claimed in claim 14 wherein the edge cover includes two side walls, each side wall being adapted for location on one side of the edge and the method includes the step of removing a portion of at least one of the walls to adjust the height of the at least one wall.

17. A method as claimed in claim 14 including the step of adhering the edge cover to the edge or to the sill.

18. A method as claimed in claim 14 including the step of sealing the support member.

19. A method as claimed in claim 14 including the step of tiling the support member.

20. A floor installation including a floor support member having a contoured surface to facilitate drainage to a selected drainage point, a sill provided at a peripheral edge of the support member to provide a peripheral floor edge that protrudes above the support member, and an elongate edge cover of a substantially rigid material having one or more walls provided about the peripheral floor edge to substantially cover the edge.

21. A floor installation as claimed in claim 20 wherein the sill comprises a peripheral edge of the support member.

22. A floor installation as claimed in claim 20 wherein the edge cover protrudes onto or over the floor.

23. A floor installation as claimed in claim 22 wherein the edge cover includes a leg adapted to contact the shower floor.

24. A floor installation as claimed in claim 20 wherein the edge cover includes two side walls, each side wall being adapted for location on one side of the edge.

25. A floor installation as claimed in claim 24 wherein at least one of the walls has an area of weakness whereby a portion of the wall may be removed to allow adjustment of the height of the at least one wall.

26. A support member having a substantially flat first surface, a second surface opposite the first surface the second surface being contoured to facilitate drainage to a selected drainage point, and being constructed from a rigid foam material and having an integral sill provided along at least one peripheral edge of the second surface, the sill protruding from the second surface.

27. A support member as claimed in claim 26 wherein the foam material has a density from about 80 to about 200 kilograms of chemical per cubic meter of final product.