EP0409626A2

EP0409626A2 - Wall parapet construction

Info

Publication number: EP0409626A2
Application number: EP90307920A
Authority: EP
Inventors: Colin James Michael Knox
Original assignee: Tarmac Bricks Ltd
Current assignee: Tarmac Bricks Ltd
Priority date: 1989-07-19
Filing date: 1990-07-19
Publication date: 1991-01-23
Also published as: GB2234271A; EP0409626A3; GB8916488D0; GB2234271B

Abstract

A wall parapet construction for a cavity wally. The construction comprises a series of Capping Units 11 a top course of bricks 12 13 for the inner and outer leaves and an interlocking member 14. The interlocking member 14 is elongate and consists of a support 15 a wire mesh 16 and a pair DPC sheets 17 18. The support 15 is made of a plastics material and has a generally A-shaped cross reference section with an additional base section in the form of a pair of outwardly extending flanges 19. The mesh 16 extends into the mortar joint between the top course of bricks and the capping unit while the DPC sheets 17 18 extend into the mortar joints between the top two courses of bricks.

Description

The present invention relates to a wall parapet construction. It is particularly applicable to cavity walls, through it can equally be used with solid walls, and is suitably for all forms of wall including walls in buildings and free standing walls.
In one known form of parapet construction, capping units are laid across the upper course of bricks forming the wall, so that the capping units span the entire wall thickness. A conventional damp proof course (DPC) may be located in the mortar joint immediately beneath the capping units or in the joint beneath the top brick course. The DPC may, of course, be stepped. These arrangements suffer the disadvantage that the DPC causes a plane (or stepped plane) of weakness, with the result that the capping units are not as secure as would be preferred; they are vulnerable to dislodgement by vandalism or may be accidentally moved, even as a result of high winds possibly following degradation of the mortar joint by the weather.
In another known arrangement, special capping units and top-course bricks are used which have interlocking profiles. Thus, there is an inherent strength in the joint beneath the capping units, however, the special capping units and bricks are relatively for more costly than standard components.
It is an object of the present invention to provide a parapet construction which is simple to install, which avoids any planes of weakness but which can use standard components.
According to the invention a wall parapet construction comprises a series of capping units, a top course of bricks beneath the capping units, a mortar joint beneath the capping units and the top course of bricks, and an interlocking member, the interlocking member including a mesh section extending into the mortar joint beneath the capping units and a base section extending beneath the top course of bricks.
The capping units may take any desired form and may be made of any convenient material such as concrete or store or they may be of a conventional brick composition. Similarly, the bricks may be of any suitable composition.
The mesh section provides a strong bond between the capping units and the wall below, and may take any open form. Preferably, however, it is in the form of an open grid. The mesh section may be of any suitable material, examples being stainless steel, galvanised or plastics coated metal, or even a durable plastics material. Preferably, the mesh section is attached to a support (or former) which also provides the base section. The base section is preferably embedded in the mortar joint beneath the top course of bricks and the penultimate course.
A DPC sheet may be attached to the support and/or base section. In a preferred arrangement therefore, the interlocking member comprises the mesh section, the support providing the base section and the DPC sheet. The DPC sheet is preferably a "high-performance" or "high-bond" DPC material such as a bitumen/pitch composite, or some other suitable high-bond material. This will tend to eliminate any plane of weakness at the DPC.
In the case of a cavity wall, in a preferred form, the mesh section extends over both the inner and outer leaves, the base section extends into the inner and outer leaves and the support is located in or above the cavity. Preferably, the DPC also extends over or through both leaves.
Conveniently, the support is elongate and has an inverted generally U-shaped cross-section with the base section taking the form of two outwardly extending flanges and the mesh section being attached to the top, e.g. by a fixing strip. There may be a cross-web extending along the inside of the support so that the cross-section is generally A-shaped. A DPC sheet is preferably bonded to the support at each side and these extend out from beneath the two flanges.
In an alternative embodiment, keying members may be attached to or may form part of the mesh section, which extend upwards into cavities in the underside of the capping units. This arrangement would provide an even stronger attachment for the capping units.
The invention also extends to the interlocking member per se which would comprise an elongate support, a mesh section attached to the support and a base section forming part of the support, the mesh section and base section both extending longitudinally and laterally outwards. The support may be of any suitable material but is preferably of a plastics material such as polyethylene or polyvinyl chloride.
The interlocking member may be provided in discrete lengths, in which case a joint system may be provided. The joint system may simply comprise a butt joint between the two ends of adjacent supports and a cover sheet laid over the joint line and any associated DPC sheets. Alternatively, the joint system may comprise a sheet of DPC moulded over an insert and located beneath the butt joint, with the insert extending into the interior of the adjacent supports and the sheet of DPC underlying the DPC sheets associated with the two adjacent supports.
According to another aspect of the invention, a method of forming a wall parapet comprises: positioning a base section of an interlocking unit on a penultimate course of bricks, the interlocking unit also including a mesh section; ensuring that the mesh section extends generally vertically; locating the base section and a top course of bricks on the penultimate course by means of a mortar joint; bending the mesh section so that it lies over the top of the top course; and laying a series of capping units over the top course by means of a mortar joint which embeds the mesh section.
A DPC sheet is preferably located in the joint beneath the top course and is fixed to the base section, preferably before the interlocking unit is placed in position. Alternatively, the DPC sheet may be positioned and subsequently the interlocking member. Preferably, a mortar joint is formed between the top course and the interlocking unit.
It will be appreciated that in the system according to the invention, standard components can be used for the capping units and for the top brick course. Furthermore, a strong bond is formed between the capping units and the remainder of the wall beneath which, when coupled with the preferred high-bond DPC, provides a very strong structure indeed.
An additional advantage of the system according to the invention is that changes of direction are made very much more simple and inexpensive than with existing systems, no special components being necessary. It is likely that the cost may be reduced by as much as 90 or 95%.
The invention may be carried into practice in various ways and some embodiments will now be described by way of example with reference to the accompanying drawings, in which:-

Figure 1 is an isometric sketch of the main components of a wall parapet construction in accordance with the present invention;
Figure 2 is an isometric view to an enlarged scale of an interlocking member;
Figure 3 is a vertical section through a wall with a parapet construction in accordance with the present invention;
Figures 4 and 5 are views similar to Figure 3 showing alternative embodiments;
Figures 6A to 6F are isometric sketches showing six sequential stages in the construction of a parapet in accordance with the present invention;
Figures 7A to 7C are isometric sketches showing three sequential stages in joining two interlocking members; and
Figures 8A to 8C are views similar to Figures 6A to 6C showing an alternative method of joining two interlocking members.

The embodiments shown are described in relation to a cavity wall, though the invention is not necessarily limited to this construction.
As shown in Figure 1, the basic components of the parapet construction are a series of capping units 11, a top course of bricks 12, 13 for both inner and outer leaves, respectively, and an interlocking member 14. As additionally shown in Figure 2, the interlocking member is elongate and consists of a support 15, a wire mesh 16 and a pair of DPC sheets 17, 18. The support 15 is made of a plastics material and has a generally A-shaped cross-section with an additional base section in the form of a pair of outwardly extending flanges 19. The mesh 16 is attached to the top of the support 15 by means of a fixing strip 21. The DPC sheets 17, 18 are bonded to inner surfaces of the support 15 and the undersides of the flanges 19.
Figure 3 shows a completed parapet construction. The DPC sheets 17, 18 and the flanges 19 are embedded in the mortar joints 22, 23 between the top brick course 12, 13 and the underlying course 24, with the DPC sheets 17, 18 just protruding. The support 15 extends up into the gap between the inner and outer bricks 12, 13 of the top course and is located there by mortar joints 25, 26. The mesh 16 is embedded in the mortar joint 27 between the capping units 11 and the top course 12, 13. The capping units 11 span the two leaves of the wall. It will be appreciated that the support 15 and the two bonded DPC sheets 17, 18 provide a moisture-proof barrier spanning the wall.
The embodiment shown in Figure 4 is similar to that shown in Figure 3 other than in one respect. The capping units 31 have recesses 32 in their under surfaces and keys 33 fixed to the mesh 16 extend into the recesses 32. In the embodiment shown, the recesses 32 are grooves and the keys 33 are elongate angle members. However, the recesses could otherwise be holes and the keys would then be bosses. As shown in broken lines, the capping unit 31 (and indeed 11) may provide an overhanging detail.
The embodiment shown in Figure 5 is a variation on the embodiment shown in Figure 4. Here, the capping units 41 have a single generally central recess 42, and the support 45 extends vertically past the level of the top of the top brick course 12, 13. The support 45 and the mesh 16, which follows its profile, is located in the recess 42.
Figures 6A to 6F show the sequence of construction of the parapet. Figure 6A shows a cavity wall completed up to the penultimate brick course 24. An interlocking member 14, in this case about 1 metre in length, is placed in position as shown in Figure 6B, with the DPC spread over a thin bed of mortar and with the mesh 16 folded around the support 15. The interlocking member 14 would be supplied with the mesh 16 in this position for ease of transportation and to minimise damage to the mesh 16.
Next, the mesh 16 is unfolded to extend vertically and the top course of bricks 12, 13 is laid (forming the mortar joints 22, 23) as shown in Figure 6C. The support 15 is then mortared in (forming joints 25, 26) and the mesh is folded back down to lie over the top course 12, 13 as shown in Figure 6D. Finally, the capping units 11 are laid on top with the mesh 16 becoming embedded in the mortar joint 27. Figure 5F shows the completed section of parapet.
The interlocking members 14 can be joined to provide a parapet of any length. One system is shown in Figures 7A to 7C. A short length of DPC 34, perhaps 10 cm, is moulded over an insert 35 to form a profile which will fit into the space in the underside of the adjacent supports 15. The two interlocking members 14 are brought together until they are abut and are placed over the DPC sheet 34 and insert 35. The components are sealed in this position.
An alternative system is shown in Figures 8A to 8C. In this case, the abutting ends of the supports 15 are stepped down as shown at 36. When they are brought together they form a saddle 37. A sealing strip 38 about 10 cm wide is then located over the saddle 37 and the joint line, and is sealed in position.
In both cases, when the joint has been formed, the construction can be continued. The joint can of course be formed at any of the stages shown in Figures 5B to 5F, as preferred.

Claims

1. A wall parapet construction comprising a series of capping units (11), a top course of bricks (12, 13) beneath the capping units (11), and a mortar joint (27) between the capping units (11) and the top course of bricks, characterised by an interlocking member (14), the interlocking member (14) including a mesh section (16) extending into the mortar joint (27) beneath the capping units (11) and a base section (15,19) extending beneath the top course of bricks (12,13).

2. A construction as claimed in Claim 1, characterised in that the mesh section (16) is in the form of an open grid and is made of stainless steel, galvanised or plastics coated metal, or a durable plastics material.

3. A construction as claimed in any preceding Claim, characterised in that the mesh section (16) is attached to a support (15) which also provides the base section, and a DPC sheet (17,18) is attached to the support (15) and/or the base section (19), the DPC sheet preferably comprising a "high-performance" DPC material such as a bitumen/pitch composite.

4. A construction as claimed in any preceding claim, characterised in that the mesh section (19) is embedded in the mortar joint (22) between the top course of bricks and penultimate course of bricks.

5. A construction as claimed in any preceding Claim intended for use with a cavity wall characterised in that the mesh section (16) extends over both the inner and outer leaves (12,13) the base section (19) extends into the inner and outer leaves, the support (15) is located in or above the cavity, and the DPC (17,18) extends over or through both leaves.

6. A construction as claimed in any of Claims 3 to 5, characterised in that the support (15) is elongate and has an inverted generally U-Shaped cross-section with the base section (19) taking the form of two outwardly extending flanges and the mesh (16) section being attached to the top, the DPC sheet (17,18) preferably being bonded to the support (15) at each side, extending out from beneath two flanges (19).

7. A construction as claimed in Claim 6 characterised by cross-web extending across the inside of the support (15) so that the cross-section is generally A-shaped.

8. A construction as claimed in any preceding Claim, characterised by keying members (33) attached to or forming part of the mesh section (16), the keying members (33) extending upwards into cavities (32) in the underside of the capping units (11).

9. A construction as claimed in any of Claims 3 to 8, characterised a joint system for joining two adjacent interlocking members (14), the joint system comprising a sheet (34) of DPC moulded over an insert (35) and located beneath a butt joint between the adjacent interlocking members (14), the insert (35) extending into the interior of the adjacent supports and the sheet of DPC underlying the DPC sheets associated with the two adjacent supports.

10. A method of forming a wall parapet, characterised in that it comprises: positioning a base section (19) of an interlocking unit (14) on a penultimate course of bricks, the interlocking unit (14) also including a mesh section (16); ensuring that the mesh section (19) and a top-course of bricks (12,13) on the penultimate course bvy means of a mortar joint (22); ending the mesh section (16) extends generally vertically, locating the base section (19) so that it lies over the top of the top-course (12,13); and laying a series of capping units (11) over the top course by means of a mortar joint (27) which embeds the mesh section (16), a DPC sheet preferably being located in the joint beneath the top course and fixed to the base section before the interlocking unit is placed in position.

11. An interlocking member for use in a wall parapet construction comprising an elongate support (15), a mesh section (16) attached to the support (15) and a base section (19) forming part of the support, the mesh section (16) and base section (19) both extending longitudinally and laterally outwards.