FIELD OF INVENTION This invention relates to a flood stop. A preferred form of the invention relates to means for preventing a flood within a room from spreading to another room.

BACKGROUND A problem with buildings, whether domestic or otherwise, is that floods such as those from an overflowing unattended bath or wash basin can cause significant water damage. The damage can spread from the room where flooding emanates to other rooms, largely depending on how long the situation is left unaddressed.

The term "comprising" or derivatives thereof (eg "comprises"), if and when used herein, should be interpreted non-exclusively - eg if used in relation to a specific combination of features it should not be taken to exclude the possibility of there also being additional unspecified features.

It should also be appreciated that orientational terms, for example "top", if and when used herein, should be taken as applying to the feature concerned when in a normal in-use orientation.

SUMMARY OF INVENTION According to one aspect of the invention there is provided a flood stop comprising a drainage dish installed in a room of a building substantially at floor level, the drainage dish having a top surface with an opening therein and a cover over the opening, the drainage dish substantially filling a space within a floor, and a floor covering supported by and substantially covering the top surface but not the opening, the flood stop arranged such that in the event of a flood of water on the floor the water can drop through apertures in the cover, into the drainage dish, and drain therefrom via an outlet; the flood stop characterised in that the floor covering substantially conceals the top surface, and wherein the floor covering covers a greater area of the top surface than the area across the opening.

Preferably the drainage dish is positioned at or adjacent a doorway such that in the event of water flooding in the room the water will drain into the drainage dish rather than proceed through the doorway into an adjoining room.

Preferably the top surface is substantially flush with the floor (less the floor covering) and the drainage dish has a depth substantially the same as that of the floor (less the floor covering).

Preferably the cover has a projection which engages a recess in the drainage dish to secure the cover against lateral movement with respect to the top surface. Optionally the projection comprises a tongue and the recess comprises a slot.

Preferably the cover has a grate.

Preferably there is a carpet edge cap running along or adjacent a peripheral edge of the grate.

Optionally the edge cap is seated in a ledge of the grate. According to a further aspect of the invention there is provided a drainage dish optionally suitable for use as the drainage dish in a flood stop as described above, the dish having a base, a top surface with an opening therein, a vacant area between the base and the top surface, a cover with apertures therein which can be fitted to lay completely across the opening in the top surface, the cover having means adapted to engage other parts of the dish to resist lateral movement of the cover with respect to the top surface, the depth of the drainage dish between the base and the top surface being from substantially 15 mm to substantially 25 mm.

Preferably the opening in the top surface occupies less than one half of the transverse foot print area of the drainage dish when the dish is in a normal in-use orientation.

Preferably the drainage dish is of a substantially elongate form.

Preferably the cover is in the form of a grate.

Preferably the grate has a tongue which can engage a groove in the top surface to resist movement of the grate in a transverse direction with respect to the dish.

Preferably the dish is combined with a carpet edge cap and the cover has a longitudinal peripheral ledge, the dish formed such that the carpet edge cap can be seated on the ledge for proper functional use.

According to a further aspect of the invention there is provided a drainage dish optionally suitable for use in a flood stop as described above, the dish having a base, a top surface with an opening therein, a vacant area between the base and the top surface, a grate which can lay completely across the opening in the top surface; the opening in the top surface occupying less than one half of the transverse foot print area of the drainage dish when the dish is in a normal in-use orientation.

BRIEF DESCRIPTION OF THE DRAWINGS Some preferred forms of the invention will now be described by way of example and with reference to the accompanying drawings, of which:

Figure 1 is a perspective cut-away view of a flood stop in the room of a building, and Figure 2 is a transverse cross-sectional view of a drainage dish forming part of flood stop with the various parts of the dish unassembled (ie prior to installation of the dish). Figure 3 is a perspective cut-away view of a shower room flood stop according to a specific embodiment of the invention, and Figure 4 provides a broader installed view the flood stop of figure 3.

DETAILED DESCRIPTION Referring to figure 1 , a preferred form of the invention involves an elongate drainage dish 1 installed at floor level in a building, whether domestic or otherwise. As shown in figure 1 , the dish 1 has substantially the same depth as the surrounding floor 2,3. The floor and the drainage dish may for example have a depth of 18mm as is common in many building situations, although it should be understood that the actual depth is not crucial to the inventive concept described herein. The use of a dish 1 of substantially the same depth as the surrounding floor means that it can be installed in a space within the floor 2,3 without interfering with an underlying joist 4. For example the dish 1 may lay directly on floor joists without any need to cut back such joists. This overcomes a disadvantage with at least some prior art drainage arrangements. The dish will of-course have two end walls, as well as the two side walls actually shown in the drawings.

With further reference to figure 1 , the drainage dish 1 has a top surface 5 with an opening 6 therein. The opening 6 is covered by a grate 7. A floor covering, for example tiles 8, proceed over the floor 2 at one side of the dish. As shown, the tiles 8 also proceed over and are fixed to the top surface 5 of the dish, but stop short of the opening 6. A further floor covering, for example carpet 9, proceeds over the floor 3 at the other side of the dish and butts up against the grate and an end cap 10. The grate 7 has a pair of spaced tongues 11 , 12 which engage respective grooves 13, 14 (see figure 2) in the dish immediately adjacent the sides of the opening 6. As shown in figure 1 , the end cap 10 may fit into a ledge in the upper edge part of the grate 7. In some embodiments of the invention the end cap may be dispensed with, and the carpet 9 butted up against the grate 7 directly. The thickness of the grate may be matched to the type of abutting floor covering, whether that be the carpet 9 or otherwise. As shown in figure 1 , the grate 7 is preferably flush with the tiles 8.

With the dish 1 arranged in the floor 2, 3 as shown in figure 1 a flood of water on the floor can drop through the grate 7, into the dish 1 , and drain therefrom by way of an outlet in the dish (not shown). An outlet can be drilled at the time of installation if desired. Preferably the dish 1 is installed across or immediately adjacent a doorway so that flooding in one room of a building cannot move into an adjoining room and cause damage there.

As conveyed above, the drainage dish 1 has substantially the same depth as the floor 2, 3. This means that it does not interfere with underlying joists, but at the same time means there is relatively little vertical space within the dish 1 to receive flood water. However the shallow depth of the dish 1 is compensated for by its width - ie the distance it spans between the two parts of the floor 2, 3. In normal situations a wide dish would present an unsightly feature in the floor of a building however with the figure 1 arrangement it can be seen that at least the major part of the dish's top surface 5 is concealed by the floor tiles 8. The opening 6 only occupies a minor part of the footprint area of the dish 1 and hence the dish can be installed to provide a discreet and effective means of channelling flood water away from room. Preferably the dish 1 is installed underneath the closed position of a door 15 between two rooms. This means that when the door is closed it at least reduces the visibility of the opening 6 and grate 7 from above.

While the arrangement at figure 1 has been described in connection with two different floor coverings, ie tiles and carpet, it can also be used in situations where there is only one type of floor covering (eg tiles, carpet, linoleum, overlay boards, etc).

In at least some embodiments of the invention the dish 1 may be adapted to have a lateral tongue and/or groove arrangement (not shown) to compliment the tongue and groove pattern of timber floor boards (ie as opposed to overlay boards). This enables the dish 1 to be inserted in tongue and groove fashion with surrounding floor boards.

In at least some embodiments of the invention the opening 6 in the top surface 5 occupies less than one half, and preferably approximately one third or less, of the distance from one side 16 of the drainage dish 1 to the other 17 (ie the transverse footprint area of the dish). The opening can however be larger or smaller to suit the conditions.

Preferably the drainage dish 1 is formed from a suitable plastics and/or metallic substance and can be installed during the construction of a building (eg a house) or otherwise retro-fitted.

Preferably the depth of the drainage dish 1 between the exterior of its top surface 5 and the exterior of its base 18 is the same as the thickness of a standard flooring material - for example an 18 mm floorboard or a sheet of 20 mm particle board. This enables a good flush fit between the dish 1 and the surrounding floor 2, 3.

In some embodiments of the invention the dish may incorporate small packers 1 b (see figure 2) to raise the height of the grate with respect to the rest of the dish if for example one is working with thicker floor coverings - ie to make sure that the grate is substantially flush with the floor coverings. The spacers may have lower male tongue parts which fit into the grooves 13 and 14 of the dish, and upper grooves of similar size to the grooves 13 and 14 to receive the tongues 11 , 12 of the grate. In some embodiments of the invention the end cap mentioned above as part 10 may be adapted so that it has a male tongue which can be inserted into a female recess of the grate, ie rather than just engaging a ledge at the side of the grate.

Referring to figure 3, a further embodiment of the invention involves a flood stop similar to that described above except that the top surface 19 of the drainage dish 20 is concealed by and supports tiles 21 , 22 either side of opening 23. The opening 23 is thus in a more central part of the dish 20. A grate cover 24 engages the top surface near the sides of the opening 23 and covers the opening 23. The flood stop of figure 3 is particularly useful in the context of bathroom shower cubicles or the like to drain away shower water running off a person taking a shower. Figure 4 shows the flood stop of this embodiment is shown as it would appear in a shower set in a bathroom floor 25 adjacent a wall 26. The wall 26 supports or houses a shower rosette and other plumbing (not shown). The arrangement may be such that a shower screen can be drawn adjacent the shower stop when desired.

While some preferred forms of the invention have been described by way of example it should be appreciated that modifications and improvements can occur without departing from the scope of the appended claims.