GB2564457A

GB2564457A - Threshold tray

Info

Publication number: GB2564457A
Application number: GB1711174.1A
Authority: GB
Inventors: Shilabeer John
Original assignee: Cavity Trays Ltd
Current assignee: Cavity Trays Ltd
Priority date: 2017-07-12
Filing date: 2017-07-12
Publication date: 2019-01-16
Anticipated expiration: 2037-07-12
Also published as: GB2564457B; GB201711174D0

Abstract

A threshold tray for closing a cavity at an opening through a cavity wall comprises an elongate body with a drainage surface for covering the cavity, and a drainage conduit which extends beneath the drainage surface from an opening in the drainage surface to provide a fluid communication pathway for conveying liquid away from the drainage surface. The threshold tray closes the cavity to prevent or minimise gas rising into the building envelope, and also allows water to be drained away from within the cavity. The tray may be part of a kit including a closer for the side of the aperture and a link member. The tray may include a drainage conduit to channel fluid to the outside of the wall.

Description

THRESHOLD TRAY

Field of the Invention

The invention relates to a threshold tray, and to a cavity wall construction incorporating such a threshold tray.

Background

Buildings are now commonly constructed using a cavity wall construction, wherein exterior walls of the building have an inner skin and an outer skin which are separated by an air cavity. The air cavity may hold an insulating material. As well as providing insulation, such a construction helps to reduce water ingress into the building.

Particularly on contaminated land, there is a need to seal the footprint of the building against gas which rises from the ground. In the exterior walls of buildings, such sealing may form part of a damp proof course which prevents damp rising through the walls. Damp proof courses may be provided in the form of a cavity tray which bridges the gap between the inner and outer skins of the cavity wall. An example of a cavity tray in a cavity wall construction 1000 is shown in Fig. 1. The cavity wall 1000 comprises an inner skin 102, and an outer skin 104 which are separated by a cavity 106. The inner 102 skin and outer skin 104 may be tied together by ties 118 to provide stability. A cavity tray 100 is typically made of a flexible polymer material which is laid within the mortar of both the inner skin 102 and outer skin 104 of the cavity wall, with a drop 110 between the inner and outer sections of around 150mm. Some known cavity trays are made of a more rigid material, with a portion of the cavity tray between the inner and outer sections being sloped downwardly towards the outer section to provide a fluid runoff path. The cavity tray provides a damp proof course in both the inner skin 102 and the outer skin 104, and so a slope is important to ensure that any water which falls onto the tray (e.g. condensation formed in the cavity, or penetrating rain) is tracked to the outer skin 104 where it is deposited to the exterior of the building via 'weep holes' 112. This helps prevent moisture entering the building envelope. The portion of inner skin 102 which is below the cavity tray 100 is protected by a waterproof membrane 116. The cavity tray 100 also prevents gas rising into the envelope of the building by providing a substantially air tight barrier, though air flow below the cavity tray may be facilitated by the presence of air bricks 114 in the outer skin below the level of the tray. In some cases, gas trapped below the cavity tray 100 may be evacuated to atmosphere through air bricks positioned above the barrier level via a gas tight connecting duct extending through the cavity tray 100. The air bricks 114 may also provide underfloor ventilation in the building by connection to a vent in a sub floor void. The cavity tray damp proof course in the outer skin 104 is generally located around 150 mm (108) above ground level, with the damp proof course in the inner skin 102 around 300 mm above ground level.

Summary

There is a problem with sealing the footprint of a building where there are openings in the cavity wall, for example at doors and windows. At such openings, the inner skin and the outer skin generally rise to the same height such that the bottom edge of the opening is level. The gas and water seal must continue across the opening, but known cavity trays are not suitable for this purpose as a section of the tray must rise above the level of the damp proof course to provide a run-off path to direct fluid to the outer skin. For example, a run-off path may be provided by the stepped or staggered construction as shown in Fig. 1. The present invention aims to address this problem.

According to a first aspect of the invention, there is provided a building construction comprising: an upstanding cavity wall having an inner surface and an outer surface, the cavity wall being formed by an inner skin and an outer skin having a cavity therebetween; an opening through the cavity wall from the inner surface to the outer surface, the opening having a longitudinally extending bottom edge along which the cavity is exposed; and a threshold tray mounted to cover the exposed cavity along the bottom edge of the opening, wherein the threshold tray comprises an elongate body with a drainage surface, the drainage surface including a fluid communication pathway for conveying liquid away from the drainage surface. The opening may be an opening in the cavity wall for a door or a window, for example. The fluid communication pathway bypasses the cavity to ensure that liquid which is received at the drainage surface does not leak into the cavity.

Preferably, the fluid communication pathway conveys liquid to an exterior of the building envelope, i.e. outside the outer surface of the cavity wall.

By providing a building construction in this way, the threshold tray is able to substantially close the cavity along the bottom edge of the opening to minimise or prevent land gases rising into the footprint of the building, and the threshold tray is also able to drain liquid from within the cavity, e.g. water which may be formed from condensation. The provision of the fluid communication pathway to drain water away from the drainage surface means that drainage occurs even where the inner and outer skins rise to the same height along the bottom edge of the opening, such that the threshold tray is substantially level. This is particularly advantageous where the opening is near ground level, for example where the opening is an opening for a door. The threshold tray may, in some embodiments, sit within the cavity where it is held by a friction fit between the inner and outer skins, and the drainage surface may be positioned at or below the opening.

The threshold tray may be provided in a single piece which covers the exposed cavity along the bottom edge of the opening, or may alternatively be provided in a plurality of pieces which may be joined together or interlock so as to cover the exposed cavity along the bottom edge of the opening.

Preferably, the building construction further comprises an aperture through the outer skin, wherein the fluid communication pathway extends from an underside of the drainage surface and terminates at the aperture. For example, the aperture may be an air brick or a weep hole in the outer skin.

Preferably, the fluid communication pathway comprises a drainage conduit extending from the drainage surface. In some embodiments, the drainage conduit may extend through the outer skin to ensure that liquid received at the drainage surface is taken to outside the outer surface of the cavity wall. The drainage surface may be positioned at a slight angle. For example, the upper surface may be angled to direct water towards the drainage conduit. Preferably, the drainage conduit includes a pipe, which may be curved, to help to prevent gas rising through the drainage conduit.

Optionally, the threshold tray may further comprise a first cover portion that may extend substantially across the inner skin along the bottom edge of the opening, and a second cover portion that may extend substantially across the outer skin along the bottom edge of the opening. In this way, the threshold tray may also provide a damp proof course in the inner skin and outer skin of the cavity all along the bottom edge of the opening, to stop damp rising into the building envelope. The cover portions may also help hold the cavity tray in place. The cover portions may, for example, be flanges which extend laterally from first and second longitudinal sides, or top edges, of the recessed channel.

Preferably, the elongate body of the threshold tray may have a substantially U-shaped cross section which may be open upwardly. For example, the elongate body may comprise a first upstanding web; a second upstanding web; and a base web extending therebetween. The base web may form the drainage surface. By providing a threshold tray with this configuration, liquid may be collected between the two upstanding webs and conveyed to the building exterior. The two upstanding webs may also serve to hold the threshold tray in position within the exposed cavity, for example by a friction fit with the inner skin and the outer skin. In some embodiments, the first cover portion may extend laterally from an upper edge of the first upstanding web and the second cover portion may extend laterally from an upper edge of the second upstanding web. Preferably, the elongate body of the threshold tray may also be configured to receive an insulating medium between the first upstanding web and the second upstanding web, so that the threshold tray may provide an insulation barrier in the cavity. The insulating medium may be porous to allow liquid to pass through.

Preferably, the opening may have an upwardly extending side edge along with the cavity is exposed, wherein the side edge and the bottom edge may meet at a corner of the opening. The building construction may further comprise a closer for closing the cavity tray along the side edge of the opening, wherein the closer and the threshold tray mate at the corner of the opening, for example in a sealing manner. The closer may extend along at least a portion of the side edge, preferably along the entire length of the side edge. In this way, the exposed cavity may be closed at the bottom edge, side edge, and the corner of the opening. The closer may be of a conventional type. For example a vertical face of the closer may be ridged to promote condensation of water and to channel water to a lower section of the closer, where it may be deposited on the drainage surface of the threshold tray.

Preferably, the threshold tray may have a greater longitudinal extent than the bottom edge of the opening, such that the threshold tray may extend sideways into the cavity at the corner of the opening. For example, this may provide a section of the threshold tray which is configured to mate with a closer along the side edge of the opening. By extending the horizontal closer into the cavity at the corner of the opening, it may be ensured that condensation forming on the closer does not leak into the cavity or track into the building but is instead channelled directly onto the drainage surface and conveyed to the outside of the outer skin. This construction may reduce the requirement for additional sealant, such as tape or a silicone sealant, where the threshold tray and closer meet, or can ensure that the seal is still effective if such a sealant fails.

In some embodiments, the threshold tray may have an upstanding section at an end of the elongate body. The upstanding section may close the cavity at the corner and along at least a portion of the side edge of the opening. The upstanding section may engage with a closer along the side edge, or may alternatively be used in a building construction where the closer is not present. The upstanding section may extend the entire length of the side edge. Preferably, the upstanding section is no more than about 300 mm in height, optimally no more than about 150 mm in height. Alternatively, in other embodiments, the upstanding section may be more than 300 mm in height.

Such a building construction may help to close the cavity substantially around the entire opening. A building construction according to the present invention may further comprise a cavity tray. For example, the cavity tray may have an inner damp proof course within the inner skin of the cavity wall; an outer damp proof course within the outer skin of the cavity wall; and a membrane joining the inner damp proof course and the outer damp proof course to provide a fluid run-off path towards the outer damp proof course, wherein the cavity tray terminates at the opening through the cavity wall. For example, at least a portion of the membrane may be sloped downwardly towards the outer damp proof course. In some embodiments, this may be achieved by offsetting the inner damp proof course vertically from the outer damp proof course to form a stepped or staggered construction. The cavity tray may close the cavity in a region of the cavity wall which is adjacent to the opening. The cavity tray may also provide a damp proof course in the inner skin and the outer skin of the cavity wall adjacent the opening. Preferably, the cavity tray is made of a flexible material, such as a polythene membrane or pitch polymer. Alternatively, the cavity tray may be pre-formed from a rigid material.

Preferably, the building construction may further comprise a link interposed between the cavity tray and the threshold tray for closing the cavity where the cavity tray terminates at an opening through the cavity wall. The link may have a unitary body with a first section having the form of a cavity tray and engaged with the cavity tray, and a second section having an elongate slot which is configured to receive the closer or the upstanding end section of the threshold tray. For example, in some embodiments, the second section may have a U-shaped cross-section comprising a first upstanding web, a second upstanding web, and a base web therebetween, wherein the U-shaped cross section forms the elongate slot. In this way, the link provides for continuous closure of the cavity through the cavity wall and along the bottom edge of the opening, by matching the shape of the cavity tray to the shape of the closer or an upstanding section of the threshold tray.

Preferably, the threshold tray may be made of a plastic material. For example, the threshold tray may be made of unplasticized polyvinyl chloride (uPVC) or polypropylene. In this way, the threshold may be rigid and durable, which is advantageous as replacing the threshold tray in the building construction is difficult.

According to a second aspect of the invention, there is provided a threshold tray for closing a cavity along a bottom edge of an opening through a cavity wall. The threshold tray comprises an elongate body with a drainage surface for covering the cavity, and a drainage conduit which extends beneath the drainage surface from an opening in the drainage surface to provide a fluid communication pathway for conveying liquid away from the drainage surface. By providing a threshold hold in this way, it is possible to substantially close an exposed cavity along a bottom edge of an opening to minimise or prevent land gases rising into the footprint of a building. The threshold tray is also able to drain liquid from within the cavity, e.g. water which may be formed from condensation, or penetrating rain. For example, the threshold tray may be used in a building construction according to the first aspect of the invention. The threshold tray may be provided as a single piece to cover the exposed cavity along the bottom edge of the opening, or may alternatively be provided in a plurality of pieces which may be joined together or interlock so as to cover the exposed cavity along the bottom edge of the opening.

Preferably, the elongate body of the threshold tray has a first longitudinal edge and a second longitudinal edge, wherein the threshold tray may further comprise a first cover portion extending laterally from the first longitudinal edge and a second cover portion extending laterally from the second longitudinal edge. In this way, the threshold tray may also be used to provide a damp proof course in the inner skin and the outer skin of a cavity wall along the bottom edge of an opening. The first cover portion and second cover portion may also help hold the cavity tray in place along the bottom edge of an opening.

Preferably, the elongate body of the threshold tray has a recessed channel, wherein the drainage surface comprises a bottom surface of the recessed channel. The recessed channel may direct liquid towards the drainage surface, and ultimately towards the opening of the fluid communication pathway.

Optionally, the elongate body of the threshold tray may have a substantially U-shaped cross section. For example, the elongate body may comprise a first upstanding web; a second upstanding web; and a base web extending therebetween, wherein the base web forms the drainage surface of the threshold tray. This arrangement may give additional stability to the structure of the threshold tray. Furthermore, liquid may be collected between the two upstanding webs to collect on the base web. The two upstanding webs may also serve to hold the threshold tray in position within the exposed cavity, for example by a friction fit with the inner skin and the outer skin of the cavity wall. In some embodiments, the first cover portion may extend laterally from an upper edge of the first upstanding web and the second cover portion may extend laterally from an upper edge of the second upstanding web.

Preferably, the elongate body of the threshold tray may also be configured to receive an insulating medium between the first upstanding web and the second upstanding web, so that the threshold tray may provide an insulation barrier in the cavity. The insulating medium may be porous to allow liquid to pass through.

Preferably, the threshold tray has an upstanding section at an end of the elongate body. The upstanding section may be providing for closing a portion of a cavity along a side edge of an opening through a cavity wall. For example the upstanding section may be substantially perpendicular to the elongate body. Advantageously, the upstanding section may be no more than about 300 mm in height, optimally no more than about 150 mm in height.

Preferably, the threshold tray may be made of a plastic material. For example, the threshold tray may be made of uPVC or polypropylene. In this way, the threshold tray may be durable so that replacement of the threshold tray is rare, and minimal maintenance is required.

According to a third aspect of the invention, there is provided a link for closing a cavity where a cavity tray terminates at an opening through a cavity wall, wherein the link has a unitary body with a first section and a second section, wherein the first section comprises: a first elongate planar element; a second elongate planar element which is parallel to, and offset laterally from, the first planer element; and a web joining the first planar element and the second planar element, and wherein the second section has an elongate slot which is perpendicular to the first and second planar elements. For example, the link may be used in combination with a threshold tray according to the second aspect of the invention, such as in a building construction according to a first aspect of the invention. The link is configured such that the first section can be affixed to a cavity tray within the cavity wall adjacent an opening, and the second section can be affixed to either an upstanding section of the threshold tray or to a closer at a side edge of the opening. For example, the link may be affixed to either part with a sealant such as a sealant tape or a silicone sealant to form a substantially water- and gas-tight seal. The link thereby provides an easy to use and convenient 'matching' element which can match the height and shape of the cavity tray to the height and shape of the threshold tray. This may ensure that the cavity between an inner skin and an outer skin of a cavity wall is fully closed.

Preferably, the second section has a U-shaped cross section comprising a first upstanding web, a second upstanding web, and a base web extending therebetween, wherein the U-shaped cross section may form the elongate slot.

Advantageously, the slot may be sized to receive a closer or the upstanding section of the threshold tray

Optionally, the link may be made of a plastic material. For example, the link may be made of uPVC or polypropylene. In this way, the link may be durable so that replacement of the link is rare, and minimal maintenance is required.

According to a fourth aspect of the invention, there is provided a kit of parts for closing a cavity along a bottom edge and a side edge of an opening through a cavity wall, wherein the kit of parts comprises a threshold tray substantially as described herein for closing the cavity along the bottom edge of the opening, and a closer for closing the cavity along the side edge of the opening. Preferably, the kit of parts may further comprise a link substantially as described herein.

Brief Description of the Drawings

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1 shows a cross section through a known cavity wall construction with a cavity tray;

Figure 2 shows a cross section through a cavity wall across a bottom edge of an opening through the cavity wall and a threshold tray according to the present invention;

Figure 3 shows an isometric view of a building construction at an opening according to the present invention;

Figure 4 shows an isometric view of a link and a threshold tray according to the present invention; and

Figure 5 shows a front view of a threshold tray and links according to the present invention.

Detailed Description and Further Optional Features of the Invention

Fig. 2 shows a cross section through a cavity wall across the bottom edge of an opening through the cavity wall and a threshold tray according to the present invention. The cavity wall has inner skin 22 and an outer skin 24 with a cavity 20 therebetween. The cavity 20 is exposed along the bottom edge of the opening. As can be seen, the inner skin 22 and outer skin 24 rise to the same height at the bottom edge of the opening. The threshold tray is indicated generally at 10, and is mounted so as to cover the cavity 20 to prevent or minimise gas rising up through the cavity 20 and into the building envelope. As can be seen, the threshold tray 10 has a generally U-shaped cross section which sits within the cavity 20 between the inner skin 22 and the outer skin 24. A base web 12 of the U-shape provides a drainage surface of the threshold tray. A conduit 14 provides a fluid communication pathway extending from an underside of the drainage surface 12, through the outer skin 24, to the outer surface of the cavity wall so that water can be taken to the exterior of the building, i.e. outside of the outer skin 24. The threshold tray 10 also comprises a first cover portion 16 and a second cover portion 18, each cover portion extending laterally from the threshold tray 10. As shown, the first cover portion 16 extends substantially across the inner skin 22 and the second cover portion 18 extends substantially across the outer skin 24. The cover portions 16, 18 therefore act as a damp proof course in the cavity wall to prevent damp rising through the cavity wall.

An isometric view of a building construction incorporating the threshold tray 10 at an opening is shown in Fig. 3. Fig. 3 shows part of an opening in the cavity wall, where the cavity tray 10 is positioned to close the cavity along the bottom edge of the opening. The opening also has an upwardly extending side edge along which the cavity is exposed, which meets the bottom edge at a corner of the opening. A closer 30 is used to close the cavity along the side edge. The threshold tray 10 extends sideways into the cavity 20 at the corner of the opening so that it engages and receives the lower end of the closer 30. The cavity 20 is then closed along the bottom edge and along the side edge of the opening. This ensures that any moisture which condensates on the surface of the closer 30 is ultimately drained to the exterior of the building envelope through the conduit 14. The face of the vertical closer 30 may be ridged to aid channelling of condensate downwards and onto the drainage surface 12 of the threshold tray 10.

As can be seen in Figs. 2 and 3, the inner skin 22 and outer skin 24 rise to the same height along the bottom edge of the opening. This provides a level opening in the cavity wall, which is required for a window or, in particular, a door. The threshold tray 10 thus has a level configuration in which the first cover portion 16 and second cover portion 18 are level across the bottom edge of the opening. A door or window sill may be positioned over the threshold tray 10 such that the threshold tray 10 may drain water which collects under the sill to the exterior of the building envelope, through the conduit 14.

Through the cavity wall adjacent to the opening, there may be a cavity tray such as shown in Fig. 1. As can be appreciated from Figs. 1 to 3, it may be difficult to ensure that a good seal is made where the cavity tray 100 terminates at the opening. This is due to the flexible material used to make the cavity tray 100, as well as the difficulty of matching the height of the tray 100 with the height of the threshold tray 10 due to the stepped or staggered configuration of the cavity tray 100 which contrasts with the level arrangement of the threshold 10.

These difficulties are overcome by providing a link 50, as shown in Fig. 4. In the depicted embodiment, the cavity tray 10 comprises an upstanding section 40. The upstanding section 40 is a substantially perpendicular end portion at an end of the elongate body of the threshold tray 10 which is configured to close the cavity along a side edge of the opening. The upstanding section 40 may, in some cases, be configured to receive a lower end of a closer 30. In this way, the cavity may be closed along a side edge, a bottom edge, and a corner of the opening.

The link 50 has a first section configured to engage a cavity tray, and a second section 58 which is configured to engage the upstanding section 40 of the threshold tray. The first section comprises a first elongate planar element 52 and a second elongate planar element 54 which is parallel to, and offset from, the first elongate planar element 52. A web 56 joins the first planar element 52 and the second planar element 54. The first section is configured to sit within a cavity wall in substantially the same way as a cavity tray 100 shown in Fig. 1. In the cavity wall, the first section can be joined to the cavity tray 100, e.g. by tape or a sealant, so as to form a fluid tight seal with the cavity tray 100 in the cavity wall. The second section 58 is configured to fit on the rear side of upstanding section 40 of the threshold tray 10.

In some embodiments the link 50 may alternatively be configured to fit directly on the rear side of a closer 30, e.g. where the threshold tray 10 does not comprise an upstanding section 40. It is also envisaged that the threshold tray 10 and the link may be formed in one piece, i.e. as a unitary element.

The second section 58 of the link 50 comprises a U-shape vertical slot having a flange extending from the end of each arm of the U-shape. The flanges may fit over the inner skin and outer skin of the cavity wall at the side edge of the opening. The link 50 may be slideable relative to the threshold tray 10 as shown by the arrows in Fig. 4. The link 50 can be affixed at the desired height to the upstanding portion 40 of the threshold tray 10, or alternatively directly to a closer 30, using tape or a silicone sealant. A continuous seal can therefore be created in the cavity wall around and adjacent to an opening by a combination of cavity tray 100, link 50, closer 30 and threshold tray 10. The sliding fit ensures that the first section of the link 50 may be positioned at a suitable height to match the height of the cavity tray 100 adjacent the opening.

Fig. 5 shows a front view of a threshold tray 10 and two links 50 for a cavity at an opening through a cavity wall. The threshold tray 10 has an elongate body for closing the cavity along the bottom edge of the opening, and two drainage conduits 14 for draining liquid from a drainage surface of the threshold tray 10. At each end of the elongate body of the threshold tray 10 there is an upstanding section 40 for closing the cavity at a side edge of the opening and also for engaging a closer. A link 50 may be slideably mounted on each upstanding section 40 so as to match the height of a cavity tray adjacent the opening to the height of the threshold tray 10 to create a continuous closure of the cavity.

Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims .

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purposes, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclose is one example only of a generic series of equivalent or similar features .

The invention is not restricted to the details of the foregoing embodiment (s) . The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A building construction comprising: an upstanding cavity wall having an inner surface and an outer surface, the cavity wall being formed by an inner skin and an outer skin having a cavity therebetween; an opening through the cavity wall from the inner surface to the outer surface, the opening having a longitudinally extending bottom edge along which the cavity is exposed; and a threshold tray mounted to cover the exposed cavity along the bottom edge of the opening, wherein the threshold tray comprises an elongate body with a drainage surface, the drainage surface including a fluid communication pathway for conveying liquid away from the drainage surface.

2. A building construction according to claim 1, further comprising an aperture through the outer skin, wherein the fluid communication pathway extends from an underside of the drainage surface and terminates at the aperture.

3. A building construction according to claim 1 or 2, wherein the fluid communication pathway comprises a drainage conduit extending from the drainage surface.

4. A building construction according to claim 3, wherein the drainage conduit extends through the outer skin.

5. A building construction according to claim 3 or 4, wherein the drainage conduit includes a pipe.

6. A building construction according to any one of the preceding claims, wherein the elongate body comprises a recessed channel that sits within the cavity, and wherein the drainage surface comprises a bottom surface of the recessed channel.

7. A building construction according to any one of the preceding claims, wherein the threshold tray comprising a first cover portion that extends substantially across the inner skin along the bottom edge of the opening, and a second cover portion that extends substantially across the outer skin along the bottom edge of the opening.

8. A building construction according to any one of the preceding claims, wherein the elongate body of the threshold tray has a substantially U-shaped cross section which is open upwardly, the elongate body comprising: a first upstanding web; a second upstanding web; and a base web extending therebetween, wherein the base web forms the drainage surface.

9. A building construction according to any one of the preceding claims, wherein the opening has an upwardly extending side edge along which the cavity is exposed, wherein the side edge and the bottom edge meet at a corner of the opening, wherein the building construction further comprises a closer for closing the cavity along the side edge of the opening, and wherein the closer and threshold tray mate at the corner of the opening.

10. A building construction according to claim 9, wherein the threshold tray has a greater longitudinal extent than the bottom edge of the opening such that the threshold tray extends sideways into the cavity at the corner of the opening.

11. A building construction according to claim 9, wherein the threshold tray has an upstanding section at an end of the elongate body for closing the cavity at the corner and along at least a portion of the side edge of the opening.

12. A building construction according to claim 11, wherein the upstanding end section is no more than about 300 mm in height.

13. A building construction according to any one of claims 9 to 12, further comprising a cavity tray, wherein the cavity tray has : an inner damp proof course within the inner skin of the cavity wall; an outer damp proof course within the outer skin of the cavity wall; and a membrane joining the inner damp proof course and the outer damp proof course to provide a fluid run-off path towards the outer damp proof course, wherein the cavity tray terminates at the opening through the cavity wall.

14. A building construction according to claim 13, further comprising a link, interposed between the cavity tray and the threshold tray, for closing the cavity where the cavity tray terminates at the opening through the cavity wall, wherein the link has a unitary body with a first section having the form of a cavity tray and engaged with the cavity tray, and a second section having an elongate slot which is configured to receive the closer or the upstanding end section of the threshold tray.

15. A building construction according to claim 14, wherein the second section has a U-shaped cross section comprising a first upstanding web, a second upstanding web, and a base web therebetween, wherein the U-shaped cross section forms the elongate slot.

16. A building construction according to any one of the preceding claims, wherein the threshold tray is made of a plastic material.

17. A building construction according to claim 18, wherein the threshold tray is made of unplasticized polyvinyl chloride .

18. A threshold tray for closing a cavity along a bottom edge of an opening through a cavity wall, the threshold tray comprising an elongate body with a drainage surface for covering the cavity, and a drainage conduit which extends beneath the drainage surface from an opening in the drainage surface to provide a fluid communication pathway for conveying liquid away from the drainage surface.

19. A threshold tray according to claim 18, wherein the elongate body has a first longitudinal edge and a second longitudinal edge, and wherein the threshold tray comprises a first cover portion extending laterally from the first longitudinal edge and a second cover portion extending laterally from the second longitudinal edge.

20. A threshold tray according to either claim 18 or claim 19, wherein the elongate body of the threshold tray has a recessed channel, wherein the drainage surface comprises a bottom surface of the recessed channel.

21. A threshold tray according to any one of claims 18 to 20, wherein the elongate body of the threshold tray has a substantially U-shaped cross section, the elongate body comprising : a first upstanding web; a second upstanding web; and a base web extending therebetween, wherein the base web forms the drainage surface of the threshold tray.

22. A threshold tray according to any one of claims 18 to 21, wherein the threshold tray has an upstanding section at an end of the elongate body for closing a portion of a cavity along a side edge of an opening through a cavity wall.

23. A threshold tray according to claim 22, wherein the upstanding section is substantially perpendicular to the elongate body.

24. A threshold tray according to claim 22 or claim 23, wherein the upstanding section is no more than about 300 mm in height.

25. A threshold tray according to any one of claims 18 to 24, wherein the threshold tray is made of a plastic material.

26. A threshold tray according to claim 25, wherein the threshold tray is made of unplasticized polyvinyl chloride .

27. A link for closing a cavity where a cavity tray terminates at an opening through a cavity wall, wherein the link has a unitary body with a first section and a second section, wherein the first section comprises: a first elongate planar element; a second elongate planar element which is parallel to, and offset laterally from, the first planer element; and a web joining the first planar element and the second planar element, and wherein the second section has an elongate slot which is perpendicular to the first and second planar elements.

28. A link according to claim 27, wherein the second section has a U-shaped cross section comprising a first upstanding web, a second upstanding web, and a base web extending therebetween, wherein the U-shaped cross section forms the elongate slot.

29. A link according to claim 27 or claim 28, wherein the link is made of a plastic material.

30. A link according to claim 29, wherein the link is made of unplasticised polyvinyl chloride.

31. A building construction according to any one of claims 1 to 17, wherein the threshold tray is a threshold tray according to any one of claims 18 to 26.

32. A building construction according to either one of claim 14 or claim 15, or according to either one of claim 16 or claim 17 as dependent on claim 14 or 15, wherein the link is a link according to any one of claims 27 to 30.

33. A kit of parts for closing a cavity along a bottom edge and a side edge of an opening through a cavity wall, the kit of parts comprising a threshold tray according to any one of claims 18 to 26 for closing the cavity along the bottom edge of the opening, and a closer for closing the cavity along the side edge of the opening.

34. A kit of parts according to claim 33, the kit further comprising a link according to any one of claims 27 to 30 .