GB2323393A

GB2323393A - Cavity tray stop end

Info

Publication number: GB2323393A
Application number: GB9705726A
Authority: GB
Inventors: George Molyneux
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-03-19
Filing date: 1997-03-19
Publication date: 1998-09-23
Also published as: GB9705726D0

Abstract

A stop end 74 for a cavity tray takes the form of a plastics "fan" whose end flange members 86, 88, may be fixed, e.g. by adhesive, to damp - proof members, e.g. lintels, such as to adjust to different angles between the faces 78, 82 thereof, the stop end being embedded in the mortar joint between bricks 92, 94 in the outer leaf 64 of a cavity wall.

Description

Cavity Trav Ston Ends Field of the invention.

This invention relates to the formation of a watertight stop end at the end of a length of damp proof material (which may be sometimes abbreviated hereon to dpc) that is being used as a cavity tray within the cavity wall of a building. Although such a dpc may be in the form of a separate strip of damp proof material, it may altematively be part of another component used in the construction of a building with such a component for example perhaps being in the form of a lintel that is being used to span the top of an opening in a cavity wall.

Background of the invention.

Where a cavity wall forms an external wall of a building, it is known that under certain climatic conditions the cavity face of the cavity wall outer wall leaf can actually run with water, but this will not be prejudicial to the design function of the cavity wall providing that such water is prevented from reaching the inner wall leaf of the cavity wall. In order to achieve that aim, any building components that span the wall cavity should be designed to prevent water from passing from the cavity wall outer wall leaf to the cavity wall inner wall leaf One such often used component of a cavity wall is known as a cavity tray, and because a cavity tray features in the present invention, such a cavity tray will now be described in more detail.

The role of a cavity tray A cavity tray (sometimes also referred to as a cavity tray dpc" or perhaps just a "dpc"), is often in the form of a strip of liquid impermeable material placed horizontally in length within a cavity wall and with its width spanning the cavity of a cavity wall. Its width is of such a dimension that allows one side edge to be sandwiched within a horizontal mortar joint forming part of the cavity wall outer wall leaf, and with its opposite side edge sandwiched in a horizontal mortar joint at a higher level forming part of the cavity wall inner wall leaf, resulting in the cavity spanning part of the cavity tray width being inclined downwards from its higher level in the inner wall leaf, down to its lower level in the outer wall leaf Therefore, any water in the wall cavity from above that may run downwards and reach the cavity tray, is deflected to the cavity face of the cavity wall outer wall leaf In the past, it was often accepted that because a cavity tray deflects any cavity water to the cavity face of the cavity wall outer wall leaf, the deflected water could simply run off the ends of the cavity tray and continue its downward passage by it running down the cavity face of the outer wall leaf below either side of the longitudinal length of the wall area that is being protected by the cavity tray. However this is no longer accepted practice, and cavity trays are now required to include means of preventing any water that may collect on them, from discharging off the ends of the cavity tray. Such means are described as "cavity tray stop ends" and which may be described throughout by either that description or as just "stop ends". Because it is a requirement that these stop ends must form a watertight arrangement in order to be effective, this requires water that would otherwise be trapped on the cavity tray, to escape to the external weather face of the cavity wall outer wall leaf, via outlets known as weepholes formed in the cavity wall outer wall leaf Such weepholes may by way of example, be formed by a hollow plastic moulding being sandwiched within a perpendicular mortar joint between two masonry units that are part of the outer wall leaf Cavity tray stop ends.

In order to function, a cavity tray stop end by definition must provide an upstanding watertight barrier at the end of the cavity tray. However, the cavity tray itself provides only a base and one upright wall of a what is in effect a channel for water, with the cavity face of the cavity wall outer wall leaf providing the other upright wall of the channel. Therefore if the stop end is in the form of an upright plate, the base and one upright side of that plate must be sealed to the cavity tray, and the other upright side must be sealed to the cavity wall outer wall leaf Consequently, it has become the accepted practice to seal (normally by using adhesive) the base and one upright end of a stop end to the cavity tray, and to sandwich the opposite end of a "plate like" stop end along with part of the plate, into a perpendicular mortar joint that occurs between two items of masonry that are part of the cavity wall outer wall leaf A complication arises because the upright face of the cavity tray against which the upright end of a stop end has to be sealed, may be upright to form a 900 angle with the horizontal base of the cavity tray, or the upright face may be inclined away from the outer wall leaf of the cavity wall by perhaps up to 30 to form say up to a 1200 angle. It is therefore the purpose ofthis invention to provide a cavity tray stop end, perhaps in the form of a plastic injection moulding, that will have means for being sealed along its horizontal base and one upright end to a cavity tray and with its end that provides an upright sealing surface being adjustable to incline by a minimum of 30 while always retaining a dam forming wall in the form of a rigid plate which takes the shortest route across a wall cavity in order to sustain a rigid pressure at all times against the vertical / inclined sealed joint. To further assist in sustaining the sealed joints, the rigid dam forming wall will intersect in a manner that will describe a cross sectional T shape, with the cross plates that support the sealing material.

It should however be clearly understood that for the purposes of the descriptions and explanations throughout, the description "cavity tray" will be used to describe a generally horizontal dpc that is intended to deflect any water within a wall cavity (that forms part of a cavity wall), away from the inner cavity wall leaf towards the outer cavity wall leaf, and that such a cavity tray may be in the form of a separate component, or a cavity tray may be in the form of a component that has other purposes but also provides a cavity tray as well. Such a component may perhaps be in the form of a lintel that spans the top of an opening in a wall.

Summarv of the invention.

According to the present invention there is provided a stop end which forms a rigid barrier wall via the shortest route across a wall cavity when the stop end is installed on a cavity tray in a cavity wall and with the stop end having means for sealing its base and one end to become a component part of a cavity tray installed in the cavity wall and at least part of the stop end rigid barrier wall after crossing the wall cavity will extend to become sandwiched in a perpendicular mortar joint that forms part of the cavity wall outer wall leaf and with the part of the barrier wall becoming flexible or semi flexible and containing means for extending a part of the length of barrier wall where it is sandwiched in a perpendicular mortar joint.

It is preferred that a stop end having a cross cavity barrier wall that extends to become sandwiched in a perpendicular mortar joint, may have the part within the mortar joint being either square, rectangular, triangular shape, or quadrant shape to describe an open or part open fan.

It is also preferred that a stop end having means for extending a flexible or semi flexible section of an otherwise rigid barrier wall where it is sandwiched in a perpendicular mortar joint may have at least part of that flexible or semi flexible section in the form of two or more tapered corrugations.

It is further preferred that a stop end that may have a rigid cross barrier wall which may become fan shaped where it is sandwiched in a perpendicular mortar joint, may have two or more tapered corrugations with the larger cross sectional part of the corrugations being spaced apart at the upward edge extremity of the fan shaped part of the barrier wall and then taper smaller in a cross sectional shape to meet at a joint point at their lower extremity which may be close to or at the intersecting point of the horizontal and upright sealing strip flanges.

Furthermore, where the lower points of the corrugations meet, the stop end may be adapted at that point to allow the corrugations to flatten themselves when the fan shape is opened or there may be a weakened area at that point to assist the opening of the fan shape..

It is yet further preferred that the upright and horizontal sealing strip flanges may be in the form of a continuous plastic flange which may be part of an injection moulded stop end to support a double sided adhesive sealing strip, and with a vertical and a horizontal extremity of a rigid barrier wall intersecting down the centre of the flat width of the flat sealing strip flanges on the opposite flat faces to those that will be used to adhere the sealing strips.

Finally it may also be preferred that the actual sealing strips may be in the form of a putty like plastic sealing I adhesive material from which protective cover strips are removed when being installed, and which are well known and accepted within the trade.

Brief DescriDtion of the Drawings The invention will now be described, by way of example only, with reference to the drawings that follow, in which: Figure 1 is a side view of a cavity tray stop end in accordance with the invention.

Figure 2 is a plan view from above the stop end illustrated in Figure 1.

Figure 3 is an isometric view of the stop end illustrated in Figures 1 and 2.

Figure 4 is another isometric view of a stop end in accordance with the invention.

Figure 5 is a structural assembly illustrating part of a cavity wall that includes a stop end.

Referring to Figure 1, Figure 2 and Figure 3 of the drawings that follow, there is shown a preformed plastic moulded stop end 10 which when seen from the Figure 1 side view will be described for the following purpose of explanation only, as fan shaped.

The stop end 10 consists of a central spine 12, which intersects with a flat horizontal flange 14 down the centre line of a flat face 16 of the flange 14, and similarly the central spine 12 also intersects with a flat vertical flange 18 down a centre line of the flat face 20 of the flange 18.

From this it can perhaps be appreciated that a cross section through the intersection between the central spine 12 and the flat horizontal flange 14 is a "T" shaped intersection, as would also the intersection ofthe central spine 12 and the vertical flange 18.

A sealing strip 22 is adhered to the outer flat surfaces of the horizontal flange 14 and the vertical flange 18. The sealing strip 22 may be in the form of one or more strips and the sealing material may be a plastic sealant material similar in texture to putty and covered with a protective covering prior to installation of the stop end onto a cavity tray.

A manufacturers name plate 24 may be embossed on the central spine 12.

In next describing the central spine 12 which is part of the stop end 10, it should be understood that the central spine 12 consists of an vertical plate which may have varying wall thicknesses with it being seen from Figure 2 by way of example the parts 26 and 28 of the central spine 12 have a wall thickness which is greater than the part 30 of the central spine 12.

The purpose of this is to offer more flexible nature to the part 30 of the central spine 12 than the more rigid or at least semi rigid parts 28 and 28 of the central spine 12 but another important difference is that the thinner wall thickness part 30 has tapered corrugations 32, 32a, 34, 34a, 36, 36a, 38 and 38a with their required flexible nature being to assist in them becoming more undulating or more flatter at the choice of the person who will install the stop end, all of which will soon become apparent.

It must first however be explained that although certain parts of the stop end 10 are described as being "rigid" or "semi rigid", the resilient nature of the materials from which the stop end may be moulded, may allow a person to physically bend those parts of the stop end without them breaking. However, design features such as wall material thickness, or weakening grooves, or weakening areas may also be included to assist movement of various parts with a weakening slot 40 and a weakening area 42 being included by way of example on the stop end 10 illustrated on Figure 3.

It should also perhaps be explained that the stop end 10 is illustrated on Figures 1 to 3 with the vertical flat flange 18 being at a 90" angle to the horizontal flange 14 and which will be referred to here as its "closed" position. In this closed position, the corrugations 32 to 38 and 32a to 38a on the central spine 12 describe the largest undulations of these corrugations that will be required. However, there may be times when a stop end is installed on a cavity tray when the otherwise vertical flange 18 may be required to be at less acute angle than 90" so it will now be explained how this can be achieved with reference to Figure 4.

On Figure 4 a stop end 44 which is similar to the stop end 10 in Figure 3 for example, here on Figure 4 has had the angle between the horizontal flange 46 and the now inclined upright flange 48 physically "opened" to an angle of 1200 resulting in the corrugations 50, 50a, 52, 52a, 54, 54a, 56 and 56a to become much flatter and less undulated than the corrugations 32, 32a, 34, 34a, 36, 36a, 38 and 38a on the stop end 10 for example illustrated on Figure 3.

From this description, it will perhaps be appreciated that one or more of the following features will help to encourage the described angle to be altered through a range of 90" to 1200: the shape of the corrugations 50 to 56 and 50a to 56a along with their material thickness and flexibility, plus the weakening groove 58 and the weakened area 60.

Figure 5 now illustrates a structural assembly comprising: a cut away section of a cavity wall 62 consisting of an outer wall leaf 64 an inner wall leaf 66 separated by a cavity 68, a window frame 70, an insulated lintel 72, and a stop end 74 in its "opened" position similar by way of example only to the stop end 44 shown on Figure 4. In describing Figure 5 the lintel 72 has an insulated box section 76 which is sat on the inner wall leaf 66 while also spanning the wall cavity 68 and then extends as a flange 78 which sits on the outer wall leaf 64.

Although the first purpose of the lintel 72 is to span the wall opening which houses the window frame 70, an important aspect of the lintel 72 for describing the present cavity tray stop end invention is that its upper horizontal wall 80 along with its upright inclined wall 82 and its lower horizontal flange 84, combine to create the main functions of a cavity tray dpc.

This is however on the assumption that the lintel 72 is manufactured from a suitable dpc material or a combination of suitable materials, with the only other function required to complete a cavity tray, being a stop end at each end of the cavity tray.

Here on Figure 5 the stop end 74 has had its sealing strip horizontal flange 86 adhered to the lintel/cavity tray horizontal flange 84 and the upright inclined stop end flange 88 adhered to the inclined wall 82 of the lintel/cavity tray 72 after the angle between the flanges 84 and 88 had been adjusted to match the required angle by the person who installs the stop end 74.

A suggested method of installation will now be explained. Assuming that bricks are being laid in a right to left direction, after the brick 90 has been laid on the outer wall leaf 64, the next brick 92 should be placed in position "dry" (which is the trade description for temporarily laying a brick in its intended position but without including any mortar). This then allows the installer to accurately identify the position of the proposed perpendicular mortar joint into which a large part of the stop end 74 will become embedded. An advantage of following this arrangement is that the stop end 74 will be fixed and adhered to the appropriate surfaces of the lintel I cavity tray before any wet mortar residue is used in the area where the stop end 74 has to be adhered to the lintel/cavity tray 72 because such wet mortar residue would not be conducive with an efficient sealing operation.

When the stop end 74 has been attached to the lintel I cavity tray 72, the brick 92 can then be laid in the normal manner by including mortar, and then the next brick indicated here by broken lines 94 is laid. Finally, it is ensured that the perpendicular mortar joint 96 which occurs between the ends of the bricks 92 and 94 and houses the stop end 74 is filled with mortar.

It can perhaps be appreciated from the foregoing descriptions, that the flexible area of the stop end 74 which allows the sealed angle of the stop end to be adjusted, is fully contained within a perpendicular mortar joint when the stop end is installed, and only a thicker barrier wall crosses the wall cavity along the shortest possible route. One advantage of this is that after the stop end 74 has been installed and the mortar in the perpendicular mortar joint had set hard, the sealed end of the stop end where it abuts the upright inclined wall of the lintel/cavity tray will still be held firmly in place even if the adhesion qualities of the sealing material fails at some later date in the life of the building. Such sustained firm pressure will also be assisted by virtue of the central spine of the stop end intersecting in a "T" shaped arrangement with the stop end sealing flanges. It will also be appreciated that the foregoing described arrangements will not require stop ends in accordance with the invention having to be "handed".

Claims

CLAIMS.

1. A structural assembly comprising a cavity wall having an inner leaf and an outer leaf separated from the inner leaf by a cavity, a leaf comprising a plurality of building blocks, and a stop end sandwiched between building blocks in one of the leafs of the cavity wall.

2. A structural assembly according to claim 1, which additionally comprises a cavity tray across the cavity on at least part of which cavity tray the stop end is located.

3. A structural assembly according to claim 2, in which the stop end is located in the region of one end of the cavity tray.

4. A structural assembly according to claim 2 or claim 3, in which there is a stop end in the region of either end of the cavity tray.

5. A structural assembly according to any preceding claim, in which the stop end is located substantially in a perpendicular mortar joint of one of the leafs of the cavity wall.

6. A structural assembly according to any preceding claim, in which the stop end is located in the outer leaf of the cavity wall.

7. A structural assembly according to any preceding claim, in which there are a plurality of substantially similar stop ends located in the cavity wall.

Claims continued.

8. A stop end for a cavity wall, the stop end comprising a base member for location on a cavity tray, a generally upright member and an extensible barrier member between the base member and the upright member, in which the extensible water barrier member includes means for varying the angle between the base member and the upright member, and in which the angle varying means is contigured to be located, in use, in a mortar joint of a cavity wall.

9. A stop end according to claim 8, in which there is a rigid extension from the upright member towards the base member, which rigid extension maintains an acute angle with respect to the base member at full extension of the upright member with respect to the base member by the angle varying means.

10. A stop end according to claim 8 or claim 9, in which the angle varying means comprises a plastics fan arrangement between the upright member and the base member.

11. A stop end according to any one of claims 8 to 10, in which the upright member and base member additionally comprise means for securing the stop end to the cavity tray.

12. A stop end according to any of claims 8 to 11, in which the base member and/or the upright member extend to either side of the extensible barrier member.

13. A stop end according to claim 12, in which the upright member and/or the base member are substantially symmetrical about the extensible barrier member.

14. A stop end according to any one of claims 8 to 13, in which the stop end comprises a water impermeable material.

Claims continued.

15. A stop end according to claim 14, in which the material of the stop end comprises a plastics material.

16. A stop end according to any one of claims 8 to 15, in which the upright member is connected to the base member.

17. A stop end according to claim 16, in which the upright member is hingedly connected to the base member.

18. A stop end for a cavity wall, the stop end comprising a base member and a generally upright member with a water barrier member extending therebetween, in which the upright member and/or the base member extends or extend on either side of the barrier member.

19. A stop end according to claim 18, in which the water barrier member is extensible and includes means for varying the angle between the base member and the upright member, and in which the angle varying means is configured to be located, in use, in a mortar joint of a cavity wall.

20. A stop end according to claim 19, in which there is a rigid extension from the upright member towards the base member, which rigid extension maintains an acute angle with respect to the base member at full extension of the upright member with respect to the base member by the angle varying means.

21. A stop end according to claim 19 or claim 20, in which the angle varying means comprises a plastics fan arrangement between the upright member and the base member.

Claims continued.

22. A stop end according to any one of claims 18 to 21, in which the upright member and base member additionally comprise means for securing the stop end to cavity tray.

23. A stop end according to any one of claims 18 to 22, in which the upright member and/or the base member are substantially symmetrical about the extensible barrier member.

24. A stop end according to any one of claims 18 to 22, in which the stop end comprises a water impermeable material.

25. A stop end according to claim 24, in which the material of the stop end comprises a plastics material.

26. A stop end according to any one of claims 18 to 25, in which the upright member is connected to the base member.

27. A stop end according to claim 26, in which the upright member in hingedly connected to the base member.

28. A structural assembly according to any one of claims 1 to 7, in which the stop end is according to any one of claims 8 to 17 or 18 to 27.

29. A structural assembly substantially as described herein, with reference to and as shown in Figure 5 of the drawings that follow.

30. A stop end substantially as described herein, with reference to and as shown in Figures 1 to 5 of the drawings that follow.