GB2471082A

GB2471082A - Combined lintel and cavity tray

Info

Publication number: GB2471082A
Application number: GB0910251A
Authority: GB
Inventors: Kieran Gannon
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-06-15
Filing date: 2009-06-15
Publication date: 2010-12-22
Also published as: GB0910251D0

Abstract

A combined lintel and cavity tray for particular use in a cavity wall, comprises a lintel and tray component (1) and a pair of insert components (2). The insert components are affixed to the opposing ends of the lintel and cavity tray to form the combined unit. Moisture entering the cavity space is drained through a series of perforations (6) and (7), located on the structural wall (14B) and discharged to a chamber below (14) formed between the two skins of the lintel and cavity tray component and the insert components. The water is free to flow on wall (14A) to the external face of the external leaf, exiting through perforations (8), located on the leading edge of the lintel. An unobstructed passage way for air to enter, circulate and exit the cavity of the wall is maintained throughout, achieved through a continuation of the lower chamber and through dedicated ventilation holes (5) located on the upper structural wall.

Description

A lintel and cavity tray unit

Field of the Invention

[0001] The present invention relates to a lintel and cavity tray.

The invention relates particularly to a lintel and cavity tray to be used in conjunction with a cavity wall or rain screen wall assembly. Comprising two components, the lintel assembly and the end insert. The end inserts are connected to the opposing ends of the lintel and cavity tray assembly, the principal component of the invention, in order to form a single, combined structural unit.

Any moisture or rain entering the cavity space is collected and drained through a series of perforations located on the structural wall and is drained to a separate, lower chamber created within the assembly of the invention. Water is free to flow to the external face of the external leaf exiting through perforations located on the leading edge of the lintel. A continuous, unobstructed passage way for air to enter, circulate and exit the cavity of the wall is maintained throughout. Cavity venting is achieved through a continuation of the lower chamber and through dedicated ventilation holes located on the upper structural wall.

Background of the invention

[0002] A cavity wall or rain screen wall, from now on referred to as a cavity wall, typically consists of an external leaf, a clear cavity and an internal leaf. The external leaf may consist of various materials such as brick, rendered masonry, timber siding, reinforced plaster or the like, and is generally chosen for ascetic appeal and durability to protect the internal leaf from damage caused by weather or the like. It is generally accepted the no external leaf material is completely impervious and that moisture or precipitation, from now on referred to as water, can pass thought the fabric of the external leaf and potentially penetrate the internal leaf. Main contributory factors for the ingress of water thru a building enclosure, is owing to a building enclosure failure e.g. cracks, faulty roof gutters or the like and pressure difference between the external environment and the internal environment of an enclosure such as a cavity. In order to prevent water from passing through from the external leaf to the internal leaf of the building enclosure, a capillary break by way of a separating cavity space, now on referred to as the cavity, is formed between the internal and external leaf's.

[0003] This separating cavity varies in depths, a nominal 20mm to 100mm, typically 40mm to 60mm but most preferably a residual cavity of 50mm. The internal leaf may be constructed of various materials and methods such as timber or metal framing, masonry block work or the like and contains materials adjacent to or within the internal leaf's assembly such as insulation, plasterboard or the like.

The internal and external leaf's are typically independent and freestanding to allow for differential movement, particularly when used with a framed internal leaf and masonry/brick external leaf and are crossed tied through the cavity by way of specialist cavity fixings and ties.

[0004] At various locations on the cavity wall, openings and penetrations such as doors, windows, service voids or the like; from now on referred to as openings, require a high level support in order to carry or retain any gravitational imposed loads that may be imposed on the external leaf at the opening points. This support is typically referred to as a lintel. A lintel retaining the outer leaf of the cavity wall as described, that is independent in form, spans across the openings and takes a structural baring, typically 150mm, on the opposite ends of the opening. A lintel, typically constructed, formed, shaped or the like by way of a rolled or pressed metal, can be manufactured by various means such as fabrication or moulding.

The lintel, by way of its formation, may bridge or close the cavity and loosely connect to the inner leaf for lateral support or restraint. This section of the lintel assembly may be considered as a cavity tray, often dressed with bituminous fabrics or building plastics, known as damp-proof membrane (DPM) in order to contain and manage water that may otherwise come in contact with the more vulnerable internal leaf of the building enclosure and assembly components.

[0005] Various onsite assembled and proprietary cavity tray dams or stop ends, from now on referred to as dams, are connected to either end of the cavity tray and overlapped by DPM's, collectively known from here on as the cavity tray assembly, in order to prevent any water that has been collected by the cavity tray, to spill over the edge of the tray and subsequently causing damage to the internal leaf and or reveals of the openings. It is intended that water collected in the cavity tray assembly is drained to the external of the building enclosure by weep holes, proprietary weep ventilators or the like, here in known as weep vents, that are sited or sit on the lintel, between the perpendicular joints of the brickwork or block work and connects the cavity tray with the external environment.

[0006] In timber frame construction, which constitutes in excess of 70% of the worlds low rise domestic housing, weep vents are utilised as ventilators in order to vent the cavity, removing water, water vapour, condensation or the like that could otherwise shorten the life expectancy of the building enclosure and assembly components. Weep vents and the cavity tray assembly, used for the provision of water management, drainage and ventilation, are only effective in use if they are compatible, assembled correctly, not damaged, deformed or blocked.

[0007] In certain circumstances, the cavity may be bridged or closed by fire stopping, a change of material to the external leaf or the like, and it is common for a continuous, horizontal cavity tray to be installed in order to manage water that may inter the cavity above such closures.

[0008] However, a considered robust detail for the management of water that may enter the cavity over cavity closures, openings or the like are reliant on the correct selection and on-site installation of compatible components such as lintel's, cavity trays, DPM's, dams and weep vents. A considerable amount of ongoing quality checks are required to ensure that the entire lintel and cavity tray assembly are installed correctly and function as per design intent. Defects, owing to a failure of any of these assembly components may go unnoticed as they are concealed within the cavity. Most defects will only manifest once they have caused a considerable amount decay and damage to the cavity wall assembly components, show signs of penetrating dampness to the inside face of the internal leaf or spalling of materials to the external leaf.

[0009] In many instances, a single weep vent is placed between the perpendicular joints of the brick or block work in conjunction with a cavity tray assembly at centres of 1200mm and in general, 2 weep vents are placed on the lintel over openings. As weep vents are installed in conjunction with mortar, sandwiched between the brick and block work, there is an inevitability that the weep vents can become compressed, deformed or blocked. As the brick or block work courses rises over the cavity tray or lintel, there is a general acceptance that some mortar spoil and cavity debris can fall onto the cavity tray, further increasing the possibility of the weep vent can becoming blocked. When this happens, water that has been collected by the cavity tray assembly seeps out under the brick or block work bypassing the obstructed weep vents and causing damage to renders and spalling of the brickwork in freeze-thaw weather cycles or the like. In instances, where unseen, accidental damage has been caused to the cavity tray assembly or where the assembly components are not correctly sealed, trapped water can spill over dams and migrate indoors, through the internal leaf causing damage to the internal fabric of the building and over time, potential, irreversible damage to the cavity wall enclosure and assembly components.

(0010] Buitding components when selected and that appear of good design and function, may work well in theory and through testing, but leaves very little in the way of margin for error' when assembled with other and sometimes incompatibles components. In a typical instance, we seek to put a number of components together in order to achieve effective management of water that may enter the cavity, namely, a lintel, retaining clips, a cavity tray, DPM's, end dams and weep vents. Failure of this assembly is common where by a single failure of one, sometimes incompatible component, can lead to the ineffectiveness of other assembly components, no matter how well they have been designed or installed.

In essence, in order to achieve a robust detail for the management of water that has gained entry into the cavity, a considerable amount of time and attention to detail would need to be dedicated to this specific function, ensuring all components fit together and don't leak. However, this specific task of water management rarely receives the attention and degree of time needed to achieve a successful outcome.

[0011] It would be desirable therefore to provide a lintel, cavity tray or similar device that reduced the number of components and assembly, of which there are currently 5, and would not suffer from the disadvantages as outlined above.

[0012] A lintel, cavity tray or similar device that has fewer components and that could be assembled off-site where there are better quality control systems would be advantageous and conducive with modern methods of construction.

[0013] In addition, it would be advantageous to provide a ventilated and drained lintel and cavity tray or similar device that would provide effective and continuous ventilation of the cavity. This would, in effect, introduce a degree of pressure equalisation or moderation of the cavity space there by limiting the amount of water been drawn across the outer leaf owing to a pressure difference.

Summary of the invention

[0014] The current invention proposes a single unit, comprising of two components that form a drained and ventilated lintel and cavity tray assembly. The compatible components will provide structural support, effective management of water by way of an intergraded chamber, assembly and connection methods and a means for maintaining a clear ventilation and drainage path.

[0015] The term lintel and cavity tray as used herein is considered to be the same as one another. The only significant differentiating feature of the present invention is the thickness of the sectional profile of wall (14A) and (14B) where by a greater profile thickness, preferably the upper most wall (14B) would act as a structural member where required by design to span on opening.

[0016] It will be understood that the term Lintel' and Cavity tray' as used herein is intended to embrace any similar device or membrane.

[0017] According to one aspect of the invention, a combined lintel and cavity tray assembly would contain a chamber, defined and separated by a two walls. The lower wall of the lintel would be impermeable as to prevent water that has been collected by the upper section of the cavity tray, from inadvertently escaping back into the building enclosure. The water would be free to flow to the external face of the outer leaf by continuous horizontal openings or perforations across the whole length of the external face of the lintel. The water would be deflected away from the face of the external face of the external wall by means of a drip-lip. The upper wall acting as a structural element, would contain an area to collect unconsolidated mortar spoil, droppings or the like and incorporate continuous perforations to drain and manage water that has entered the cavity.

(0018] The continuation of perforations (6) and (7) along the entire length of upper wall (14B), gives a greater chance for effective drainage to be achieved in the event of any localised blockages caused by mortar spoil or cavity debris.

By including a separated chamber within the embodiment of the invention, there is a reduced chance for the lower wall (14A) from becoming damaged or punctured owing to cavity debris. As mortar and debris are effetely retained from entering the lower chamber (14), a clear route is maintained for water to flow to the external of the building enclosure thru perforations (8) located on the outermost face of the invention.

[0019] A second aspect of the invention incorporates a continuation of the lower chamber. Defined by a continuation of the two walls (14A) and (14B), the lower wall would be impervious. The upper wall would contain continuous perforations along the whole length of the cavity tray to enable continuous venting of the wall cavity. Continuous perorations across the whole length of the external face of the lintel would provide a route for air to exchange from within the cavity via the uninterrupted chambers. The continuation of perforations (5) along the entire length of upper wall gives dedicated ventilation points that will facilitate effective ventilation of the cavity. The walls at this point would preferably be splayed at an angle as to deflect any mortar droppings or cavity debris. The clear uninterrupted chamber would allow for consistent exchange of air thru perforations (8) located on the outermost face of the lintel. The function of effective cavity ventilation, in order to equalize or moderate a cavity pressure difference would take precedence over drainage. However it is appreciated that ventilation and drainage are of equal importance, particularly when used in association with a timber framed constructed internal leaf.

[0020] A third aspect of the invention incorporates an insert, to blank off either end of chamber effectively forming a dam. The two key components of this insert would incorporate a pad that would serve the purpose of sealing the chamber as well as providing a structural baring for the lintel when places across the opening.

When assembled with the main embodiment of the invention, the insert would effectively connect the chamber wall's enabling the whole lintel to work in unison, giving rise to a combined structural strength across the depth of the external leaf.

The second key component would incorporate a cavity dam that would contain water collected by the cavity tray until the water could seep away through perforations in the upper wall. The insert, by design, allows for a continuation of the cavity tray where necessary, adaptable to various angles where necessary, preferable 90 degree internal and external corners. A notable advantage for this component would be to provide a sealed, tight and consistent fit, mirroring the sectional profile of the main embodiment of the invention. When installed, the pad would provide a stable, structural bearing for the lintel, distributing any imposed gravitational loads to either side of the opening.

[0021] A fourth aspect of the invention incorporates a means to connect the invention to the inner leaf, allowing for differential movement between the external and internal leaf's of the cavity wall assembly. A key-hole style perforation, located on the uppermost section of the invention (15) would allow of ease of installation and adjustment to suit the external leaf block or brick coursing. A simple pinned, nailed or similar connection with the internal leaf of the cavity wall would provide a satisfactory stable connection, until such time as the external leaf masonry has cured or set and begin to self-support in association with the lintel. The connection would support the lintel and cavity tray assembly until such time as the external leaf was constructed. The pinned connection would be allowed to slide in a vertical motion. It is noted that this differential movement is small but never the less a vital as to avoid structural defects between the two leafs of the cavity wall. This method of connection effectively negating the need for separate components or fixing clips.

(0022] Further advantageous aspects of the invention will become apparent to those skilled in the art upon review of the following description of specific embodiments of the invention and with reference to the accompanying drawings.

Brief description of the drawings

[0023] An embodiment of the invention is now described by way of example and with reference to the accompanying drawings, in which: * Figure A is a perspective view of the invention incorporating the two principal components of the invention, the lintel and cavity tray assembly and end inserts. Arrangement as shown represents a lintel configuration.

* Figure B is a perspective view of the invention incorporating the two principal components of the invention, the lintel and cavity tray assembly and inserts. Arrangement as shown represents a continuous cavity tray configuration.

* Figure C is a front elevation view of the invention. A lintel, shown in situ over an opening.

* Figure D is a front elevation view of the invention showing a continuous cavity tray shown in situ.

* Figure E is a cross section of the invention shown in situ when arranged as a lintel of a timber framed opening.

* Figure F is a cross section of the invention shown in situ when arranged as a cavity tray and in conjunction with a cavity barrier.

* Figure G is a cross section of the invention identifying cavity debris and demonstrating the movement of air and water to and from the cavity.

* Figure H is a cross section of the invention, identifying an alternative battened and counter battened external cavity wall leaf and continuous cavity venting whilst maintaining effective drainage.

* Figure J is a cross section of the invention identifying an alternative arrangement of the invention when used with masonry internal leaf.

* Figure K is a cross section of a typical timber framed cavity lintel, assembly components and cavity debris.

* Figure L is a cross section of a typical masonry cavity lintel, proprietary assembly components and cavity debris.

Detailed description of the drawings

[0024] Referring now to accompanying drawings, and in particular reference to Figure A and Figure E, identifies a prospective and sectional view of the primary component, the invention (1), a combined lintel and cavity tray assembly incorporating a continuous lower chamber (14) and a higher level chamber (10).

The secondary component (2) the inserts, incorporates three distinctive features namely a lower structural dam and pad (11) a splayed or angled upper dam section (13) and a cavity dam (12).

[0025] In the preferred embodiment of the invention, the primary component (1), consists of an upper wall (14B), that would be considered structural in nature, would contain perforations (7) across the entire length of the lintel. The principal function of these perforations (6) will be to drain water that has entered into the cavity, to the lower chamber (14). The size and shape of the perforations (6) and (7) will be such as to contain larger quantities of mortar, stones cavity debris or the like from entering the lower chamber (14) but maintaining good seepage and flow of water in order for it to be effectively ejected from the cavity tray. A nominal diameter for perforations (7) would be in the order of two millimetres to four millimetres and most preferable three millimetres. The perforations (7) as illustrated, is of the preferential shape -circular. However, it will be understood that the shape, size, specific location, frequency and spacing of the perforations may be of any suitable shape, size location or spacing. The depth of the wall section (14B) will be such as to facilitate the depth of the external leaf material, plus a nominal ten millimetres, area (19), the distance margin between the internal face of the external leaf and the intermediate continuation wall section (14B).

[0026] The intermediate section of this wall (14B) would be preferable turned upward at ninety degrees to the lower section of the wall section in order to give structural rigidity to the entire length of the lintel. It will be understood that this intersection point can be turned or splayed at any suitable angle. The perforations (6) located along the entire length of this wall section, would preferentially be slightly larger diameter in size and complement the function of perforations (7).

Perforations (6) would in essence act a backup cavity drain in the event of larger quantities of water entering the cavity or in the event of localised blockages of perforations (7). A nominal diameter for perforations (6) would be in the order of two millimetres to six millimetres and most preferable four millimetres. The perforations (6) as illustrated, is of the preferential shape -circular. However, it will be understood that the shape, size, specific location, frequency and spacing of the perforations may be of any suitable shape, size location or spacing.

[0027] A continuation of the uppermost wall (14B) of the lintel will be angled or splayed, preferable at fifteen to seventy degrees, most preferably thirty degrees to the intermediate section of this wall in order to deflect any water, mortar or cavity debris droppings. Preferably, a series of perforations (5) will extend throughout the entire length of the lintel in order to provide a ventilation path for air to flow and to ventilate the cavity. A nominal diameter for perforations (5) would be in the order of four millimetres to eight millimetres and most preferable six millimetres. The perforations (6) as illustrated, is of the preferential shape -circular. It will be understood that the shape, size, specific location, frequency and spacing of the perforations may be of any suitable shape, size location or spacing. It will be understood that the preferable angle thirty degrees of this section of wall (14B) will be at any suitable angle and to suit the overall width of the cavity (17), and to effectively deflect water, debris or mortar that may drop onto it.

[0028] A continuation of the uppermost wall (14B) will continue in order to finish flat against the external face of the internal leaf (16) of the cavity wall. This section of wall, identified as (15), will effectively be at an angle of ninety degrees to the first section of the upper lintel wall (14B). This section of the lintel will accommodate fixing points (3) at nominal centres of four hundred millimetres. The size and shape of the key-hole openings will be such as to facilitate suitable pins, nails, screws (4) or the like. The overall height of the fixing point (3) will be suitable to allow for a degree of differential movement between the external leaf (18) and the internal leaf (16) and to allow for adjustment for brick or block coursings of the external leaf (18). The head of the pins (4) will be equal in diameter to the key-hole shaped fixing point (3) to allow for ease of installation and removal where necessary. The pins (4) will be attached, fixed, nailed or screwed where appropriate to the internal leaf (16) and not over tightened as to restrict differential movement between the internal leaf (16) and the lintel (1), that has baring on external wall (18).

(0029] Lintel section (15) would continue downward and connect or continue to form section (14A) that would mirror the shape, size and angles of (14B). This section of lintel, effectively offset from (14A) would be impervious where noted and would remain so throughout the entire length of the lintel and cavity tray assembly (1). The separation area formed between (14A) and (14B) would effectively form chambers (10) and (14). Lintel section (14A) would continue outward to the outermost face of the lintel and cavity tray assembly (1) and form a downward angled drip-lip (9). In the preferred embodiment of the invention (1), the entire Leading edge of the invention would contain, connect or continue to form a permanent sealed or bonded connection with lintel wall's (14A) and (14B). This section would contain perforations (8) throughout the entire length of the lintel.

The perforations (8), would most preferably be circular in shape as illustrated, to provide a means to drain water away from the lower chamber (14) and to provide thru ventilation to the cavity via the uninterrupted chambers (14) and (10). It will be understood that the shape, size, specific location, frequency and spacing of the perforations (8) may be of any suitable shape, size location or spacing in order to achieve a suitably vented cavity (17) whilst restricting the ingress of large insects and precipitation. A nominal diameter for perforations (8) would be in the order of four millimetres to eight millimetres and most preferable six millimetres.

A preferred effective free area, four hundred to eight hundred square millimetres per linier meter of lintel or cavity tray will be acceptable, most preferable, an effective free area of five hundred square millimetres per linier meter. It will be understood that any suitable area, effective or equivalent, for the provision of venting the cavity (17) may be employed.

[0030] Preferably, the overall height of the leading edge containing perforations (8) and thickness of lintel walls (14A) and (14B) throughout the entire length of the lintel and cavity tray assembly (1) would be ten millimetres, consistent with a standard, horizontal brick joint. It would therefore be preferable that the overall sectional profile thickness of the upper lintel wall (14B), that forms the structural element of lintel, would be two point five millimetres. The preferred overall sectional profile thickness of the lower wall (14A), that effectively forms the cavity tray element of lintel (1), would be one point five millimetres. The resulting sectional profile thickness of the chambers (10) and (14) would be a preferable six millimetres throughout the entire length of the lintel and cavity tray assembly (1).

It will be understood that shape, profile depth and various combinations of upper wall (14B), the lower wall (14A) and remaining chamber profile depth, will be at any suitable depth or depths to suit the overall depth of the leading edge and in order to maximise the profile depth of chambers (10) and (14).

[0031] it would be preferable for the primary component (1), the lintel and cavity tray assembly, is constructed using extruded aluminium, stainless steel or composite material such as plastics or the like, most preferable stainless steel.

However, it will be understood that any suitable material, fabrication or moulding method that achieves the required formation, structural rigidity, longevity and corrosion resistance will be suitable. The perforations would be formed by drilling, cutting or punching or the like, most preferable drilled prior to installation.

It will be understood that any suitable method for the formation of perforations (5), (6), (7) and (8) may be employed.

[0032] The second component of the of the lintel and cavity tray assembly (1) is the lintel end insert (2). The insert would preferably comprise, a solid flat bearing pad (11) would be inserted into the opposing ends of the primary component (1) and match the sectional profile of the lower chamber (14). An exacting profile fit would enable the insert to be tapped into place, be held in place by means of friction and to seal, effectively forming the lower chamber (14) dam. When installed into each end of the lintel and cavity tray assembly (1), the formation and function of the lower chamber (14) would be complete. The secondary function of the pad (11) would be to form an end support for the lintel, providing a stable baring for the lintel to sit when placed over an opening on the external wall (18). When spanning an opening and downward loads are imposed, the upper lintel wall (14B) and lower cavity tray (14A) wall would be able to work structurally in unison at this intersection point. Figure C identifies an elevation of an opening and the invention, components (1) and (2) in situ. Current engineering physics suggests that the upper gradational loads of the wall opening will pass either side of the opening and transfer down either side of the opening reveals. An acceptable baring either side of the opening of one hundred and fifty millimetres will be consistent to the length of pad (11).

[0033] Pad (11) will continue and connect thru to the upper chamber dam (13).

This end connection will effectively form a dam for the upper chamber (10) and complete the formation of the upper chamber (10). In the preferred embodiment, this end dam will be shorter in length to the lower connection pad (11) to enable an increased area for ventilation and drainage for the cavity. The dam (13) will similarly match and form an exacting profile and fit and mirror the profile and size of the upper chamber (10). It will be understood that size, shape and profile will be suitable to match the size, shape and profile of any similar chamber or end dam.

[0034] Pad (11) and chamber dam (13) will be similarly continue and connected thru to a cavity tray end dam (12). The cavity tray dam (12) will be sized and shaped, preferably as illustrated, in order to perform effective containment of water that has been collected by the upper cavity tray assembly (14B), up until such time the water has an opportunity to seep or drain thru perforations (6) and (7). It will be understood that size, shape and profile of cavity dam (12) will be suitable to match the size, shape and profile of any similar chamber or end dam.

[0035] Preferably, the secondary component (2), that contains a structural pad (11), a upper chamber dam (13) and a cavity tray end dam (12) that it will be constructed using a dense moulded plastic or the like, in one single unit. However, any similar material, fabrication or moulding method may be employed. The insert (2) will be held in place using friction, sealant or bonding, most preferable bonded to the main body of the invention (1). It will be understood that any suitable method for connection may be employed.

[0036] Referring now to Figure G, the invention is identified by a cross section view of the lintel and cavity tray assembly (1).

It is generally accepted that some cavity debris and mortar (19A) can fall onto the cavity tray. In order to maintain air flow (21) a clear path must be maintained through chambers (14) and (10). The unconsolidated debris (19A) would inevitably interrupt air flow to the cavity but it is contained in area (19). Water (6A) and (7A) is permitted to drain through perforations (6) and (7). In this regard, priority for cavity ventilation is achieved through a clear chamber (10) and (14) and through perforations (8) and (5). It is acknowledged that that air (21) can move in and out of the cavity (17) by various means, pressure difference, stack effect or the like. In order to achieve ventilation priority, preferably the perforations (6) and (7), as detailed earlier, would be smaller in size to perforations (5) as to permit drainage but to retain debris (19A). It will be understood that the lower wall (14A) may be angled or sloped a slight angle, preferable zero to one degree, most preferable zero point five degrees, from to back to front in order to provide free drainage of the chamber (14) to the external environment via perforations (8) located on the external face of the cavity tray (1). However, any suitable angle may be employed.

[0037] Referring now to Figure H and F, where required by design and function, the primary component (1) would incorporate thru-cavity ventilation (21) through perforations (5) located on both the upper and lower wall's (14B) and (14A) whilst maintaining effective cavity drainage. As illustrated, the drawing represents a battened (24) and counter battened (23) siding or cladding (22) directly supported by the internal leaf, in this instance a timber frame. The detail of the cavity (17) varies substantially according to the cladding (22) detail used.

Localised blockages e.g. cavity fire batt, identified as detail (20).

[0038] Figure C and Figure D, illustrates an embodiment of the invention (1), shown in situ in a cavity wall. In one instance the invention (1) is been utilised a lintel over an opening and in the next, a continuous cavity tray arrangement. In both instances, there is an identifiable modification between component (2) and (2A) that is illustrated on Figure A and Figure B. [0039] Figure 3 proposes an obvious alternate design to be used in conjunction with a masonry cavity construction assembly method. In this instance, perforations (5), (6) and (7) would share a common function of cavity drainage, but again, collecting unconsolidated cavity debris in area (19) and maintain a clear uninterrupted chamber (10) and (14) for the purpose of draining the cavity.

An additional chamber (14C) would be preferable to contain insulation where required and grounds for fixing doors, windows or the like.

[0040] Figures K and L, identifies a typical cavity wall lintel arrangement (26), weep vent insert (25) and timber frame retaining clip (27). A number of proprietary cavity dam (28) and alternative on site-constructed dams (29) provide little in the way of effective management of water that has entered into the cavity (17) owing to sometimes incompatible components, leading to a poor fit or deterioration of the DPM fabric and sealants over time. Cavity debris (19A) can easily blocks the weep vent (25) and where the weep vent is required to provide ventilation of the cavity space (17) e.g. in a timber frame situation, the lack of air flow can compromise the structural effectiveness and longevity of timber and cavity wall assembly components.

[0041] Although the invention (1) and (2) has been describes primarily as a horizontal lintel or cavity tray assembly for use in a cavity wall assembly, the invention may be adapted to provide a vertical cavity break at junctions such as party walls or the like in order to provide thru ventilation or at angles such as adjoining gable roofs. The invention may be installed at the base of a building to form a capillary break, cavity drainage or the like in lieu of a damp proof course.

[0042] The invention is not limited to the embodiments described herein which may be modified or varied without departing from the scope of the invention.

Claims

Claims 1 A combined lintel and cavity tray unit comprising a formed perforated support wall, an offset impervious wall and an insert, affix to the opposing ends of the primary component, creating a chamber and to attain a combined structural rigidity across the complete unit.
2 A combined lintel and cavity tray unit according to claim 1 in which a continuous perforated leading edge is interconnected to the perforated support wall, via the chamber in order to provide continuous venting and drainage to the wall cavity.
3 A combined lintel and cavity tray unit according to claim 1 in which one or more apertures permit unrestricted connection to the structure.
4 A combined lintel and cavity tray unit according to claim 1 in which the primary and secondary components are connected forming a single structural component.
A combined lintel and cavity tray unit according to claim 1 in which the formation of the primary component is varied.
6 A combined lintel and cavity tray unit according to claim 1 in which the formation of the secondary component is formed creating a single component.
7 A combined lintel and cavity tray unit according to claim 1 in which the perforations are sized as to prevent the ingress of large insects and precipitation.
8 A combined lintel and cavity tray unit according to claims 1 and 6 in which secondary component provides for the means for continuous connection and change of directions.
9 A combined lintel and cavity tray unit according to claims 1 and 5 in which cross-sectional profile depths and angles can be varied.
A combined lintel and cavity tray unit according to claims 1, 2 and 7 comprising an array of perforation sizes and shapes.
11 A combined lintel and cavity tray unit according to claims 1, 5 and 6 in which the formation of the primary and secondary components are constructed of a durable material with significant structural attribute.
12 A combined lintel and cavity tray unit according to claims 1 and 5 in which a drip-lip is incorporated into the primary component and a cavity dam is incorporated into the secondary component.