GB2200929A

GB2200929A - Inserts for constructional walls

Info

Publication number: GB2200929A
Application number: GB08702478A
Authority: GB
Inventors: George Molyneux
Original assignee: Radway Plastics Ltd
Current assignee: Radway Plastics Ltd
Priority date: 1987-02-04
Filing date: 1987-02-04
Publication date: 1988-08-17
Also published as: GB8702478D0

Abstract

An anchoring socket receives an angled retaining strap which is used to secure the wall 102 to another structure and comprises a box-like entry portion which is built into the structural elements of a wall and has an opening which in use is the inside of the wall and a box-like retaining portion 66 disposed at right angles to the entry portion and which in use fits the cavity 104 and rests against the outwardly facing surface of the inner leaf. The socket may additionally act as a ventilator or wall tie and be provided with a rigid damp proofing element projecting from the wall of the tube. <IMAGE>

Description

"Inserts for constructional walls" The invention provides an insert for building into a constructional wall (i.e. a wall of a building). Essentially, the invention is concerned with two kinds of insert, namely (1) an anchoring socket for a structural tie, and (2) a ventilator. The two kinds of insert will be separately described, although there are features which are interchangeable, and the ventilator insert can also, in certain circumstances, perform the anchoring socket function.

The anchoring socket has been conceived to meet problems which arise with modern gang nailed roof truss construction, which is employed in the great majority of house building projects in the United Kingdom at the present time. A gang nailed roof truss construction avoids the use of purlins, and consequently, it is not possible to rely on the purlins to rescrain-lateral movement of gable end and internal divider walls. Instead, it is necessary to use lateral restraint straps.

A lateral restraint strap is a metal tie for holding the end wall to the roof structure (i.e. it resists outward movement of thewall.relatively to the roof structure).

Typically, a lateral restraint strap is a galvanised steel bar 30 millimetres wide and 5 millimetres thick, having a straight main section (in which a series of nail holes is formed) of say 1 meter length and a hook portion bent at 90 degrees to the main portion at one end thereof, the hook portion being say 100 millimetres long.

In use, the main portion of the lateral restraint strap is nailed to the underside of the roof rafters or to noggings fixed between the rafters - part of the main portion extends through or lies on top of the inner leaf of a cavity wall, and the hook portion engages against the outer face of the inner leaf. Hence, the lateral restraint strap hooks the inner leaf of the wall to the roof structure and the outer leaf is, of course, secured to the inner leaf by conventional wall ties.

For completeness, it will be mentioned that there should be packing between the end rafters and the wall to transmit compression forces if the wall tends to move inwardly. It should also be understood, that in some circumstances, the lateral restraint straps are connected to the joists of floors instead of to the roof rafters.

There are severe problems, some of which appear to have no entirely satisfactory solution, associated with the use of lateral restraint straps. Without enumerating all these problems, it can be said that several arise from the fact that they require co-operation between two separate trades (bricklaying and carpentry) and others arise from the physical difficulty of aligning a strap which on the one hand should be secured to the underside of a sloping rafter or at least to noggings fixed to the sloping rafters, and on the other hand has to be hooked onto an appropriate uncut block of the wall structure.

According to a first aspect of the invention, an anchoring socket intended to be built into the wall of a building, for receiving an angled retaining strap used to secure the wal to another structure, comprises a boxlike entry portion adapted to be built into the structural elements of a wall and having an opening which in use is on the inside of the wall, and a box-like retaining portion disposed at right angles to the entry portion and adapted in use to rest against an outwardly facing surface of the wall, so that: the wall engaging part of an angled retaining strap can be introduced into the anchoring socket through the opening in the entry portion when the said wall engaging part extends widthwise of the entry portion; when the wall engaging part is aligned with the retaining portion, the retaining strap can then be turned to bring the wall engaging part into the retaining portion and wherein it can be drawn into engagement with the outwardly facing inside face of the retaining portion.

Preferably, the socket is provided with one or more mortar keys projecting outwardly from the entry portion.

Such a mortar key may comprise a rib extending laterally of the entry portion and in the preferred construction, there are mortar ribs on both the top and bottom sides of the entry portion.

According to another preferred feature of this aspect of the invention, the socket is provided with a cavity spacer projecting outwardly for engagement with the inwardly facing surface of the outer leaf of a cavity wall when the retaining portion is located in the cavity. This projection can be arranged so that for a given cavity width, the overall thickness of the retaining portion and its cavity spacer, from front to rear, is approximately equal to the cavity width, so that it is ensured that the socket is fitted with the retaining portion in engagement with the outer face of the inner leaf of the cavity wall. This is the correct location of the retaining portion to ensure that any inwardly directed pressure applied to the- retaining portion by the wall engaging part of a retaining strap is transmitted through the socket to the inner leaf of the wall.

It is further preferred that the retaining portion has a lip or flange projecting outwardly all round the periphery of the retaining portion to form a moisture drip irrespective of the orientation of the socket in the wall (i.e. with the retaining portion extending from the entry portion downwardly; upwardly or to one side). It is preferred that this lip forms a continuation of that wall of the retaining portion which closes the outer end of the inlet portion.

According to another preferred feature of the invention, the internal corner between the entry portion and the retaining portion is rounded or chamfered to ensure engagement of the wall engaging portion of the lateral restraint strap with the internal face of the retaining portion.

According to another preferred feature of this aspect of the invention, the anchoring socket is made in moisture resistant and water impermeable material.

It may for example be moulded in polyvinylchloride or polyethylene. It maybe made from two injection mouldings welded together, or it could be made from an extrusion cut to short lengths and with end plates welded to its open ends.

It is a further preferred feature of the invention that the interior of the anchoring socket is only open to the inside at the inlet to the entry portion. This ensures that when the socket is in position, it does not form a passage through which flames or smoke can pass into or out of the cavity in the wall. However, and as an additional safeguard, it is preferred to provide each socket with a flexible bag filled with flame retardant material (e.g. fire resisting fibres such as rock wool or insulating powder), this bag being of such size that when stuffed into the entry portion after fitting of the lateral restraint strap, it provides an effective fire barrier within the socket. Preferably, the bag is attached to the socket by a flexible connection so that it remains with the socket during transport and fitting.

According to a second aspect of the invention a structural assembly comprises a cavity wall having inner and outer leaves with a lateral restraint strap securing at least the inner leaf of the wall to another structural feature (e.g. roof or floor structure), there being an anchoring socket in which a hook portion of the lateral restraint strap is received, the anchoring socket comprising a box-like entry portion built into the inner leaflet of the wall and having an opening on the inside of the inner leaf, and a box-like retaining portion in internal communication with the interior of the entry- portion, the retaining portion lying within the cavity, and in engagement with the outwardly facingsurface of the inner leaf, the hook portion of the lateral restraint strap lying within the retaining portion of the anchoring socket and in engagement with the- inside of the wall of the retaining portion which engages with the inner leaf of the wall, the main section of the lateral restraint strap extending through the entry portion of the anchoring socket and out through the opening in the entry portion.

In this arrangement, the anchoring socket forms part of the wall structure, since it is built into the inner leaf of the wall and it provides the part of the wall structure against which the hooked wall engaging portion of the lateral restraint strap is engaged to effect the tie between the wall and the other stucture (roof or floor). However, the socket provides various advantages over the conventional structure, which does not employ an anchoring socket, some of which will appear hereinafter.

Preferably, the width of the entry portion exceeds the length of the hook portion of the lateral restraint strap and the depth of the entry portion exceeds the width of the hook portion. This enables the hook portion of the strap to be pushed through the entry portion from the inside and, when it is aligned with the retaining portion, turned to bring it into the retaining portion.

The turning action to fit the strap will be-further understood from the consideration that the width of the strap extends in the direction of the depth of the entry portion when the hook portion is travelling through the entry portion, but widthwise of the entry portion after turning to bring the hook port into the retaining portion.

Since the depth of the entry portion must be much greater than the thickness of the strap, and in the finished structure, the thickness of the strap occupies only a small part of the depth of the entry portion, the socket provides for vertical deflection of the other structure relatively to the wall without disengagement of the strap from the socket. This is an important advantage, and it arises from the fact that despite the secure anchoring effect of the socket on the strap, the strap is not actually fixed in the wall (as it would be if it were embedded in a mortar joint). On the other hand, since the entry portion completely surrounds the main portion of the strap, the latter cannot lift out of engagement with the wall as could a strap merely hooked over the top edge of an internal leaf, particularly if it were hooked onto a cut block.

Indeed, it will be appreciated that because the depth and width of the entry portion are much greater than the thickness and width of the lateral restraint strap, there is considerable flexibility in the location of the strap relatively to the other structure and this- greatly facilitates fixing. For instance, in the building of a gable end,whereas with the conventional technique, the bricklayer and carpenter have to work together after the roof trusses are fitted, so that the locations of the lateral restraint straps can be ascertained by reference to the position of the rafters and the blocks of the inner leaf of the wall, with the anchoring socket structure provided by the invention on the other hand, after the roof trusses are fitted they will align with appropriate fixing positions on the roof structure.Hence, use of the anchoring socket reduces or even eliminates the necessity for co-operation between bricklayers and carpenters on site. A concomitant 'advantage is that the lateral restraint straps are fitted by the carpenter who can easily engage the straps in the already provided sockets.

It is further preferred that the retaining portion is no more than half the width of the cavity; this ensures that if mortar lodges on top of the retaining portion, it will not bridge the cavity.

It is to be understood that the socket can be secured in the inner leaf of the wall in any one of four orientations, i.e. retaining portion extending vertically below the inlet portion; retaining portion extending vertically above the inlet portion, or retaining portion extending to one side or the other of the inlet portion.

If the sideway extension position is used, then the inlet portion will have its width in a vertical plane and that portion must be built into avertical joint of the wall.

The four possible orientations of the anchoring socket greatly enhance the flexibility of the structure provided by the invention and in particular, alignment of the inlet with features of the other structure to which the wall is to be secured by the lateral restraint straps.

The other structure to which the wall is secured by the lateral restraint straps may be another wall built at right angles to the socket containing wall. In that case, the main portions of the straps are simply embedded in the horizontal mortar joints of the other wall.

The anchoring socket used in this aspect of the invention may have any of the preferred features of the socket provided by the first aspect of the invention.

The ventilation of building voids, such as roof space and under floor space, is now regarded as very important, and is the subject of legislative regulation.

The need for adequate ventilation has increased with increasing use of thermal insulation, particularly in loft spaces. On the other hand, adequate ventilation is sometimes difficult to achieve with the available materials. Under floor ventilation for instance is restricted because the vertical distance between the horizontal damp proof course below the floor and the ground outside the building is frequently no more than three brick courses. Because ventilator bricks must be'adapted to deteringress of water - even in driving rain conditions - the total ventilation area available through a brick is very restricted; but increasing the number of ventilator bricks reduces the strength of the wall, and a large number would spoil the visual effect.

The ventilator provided by the invention provides an effective solution to many of these problems.

According to a third aspect of the invention a ventilator for use in a cavity wall of a building comprises a tube, having an inlet at one end and an outlet at the other end, the inlet being formed in a surface which does not face directly outwards from the end of the tube, and a rigid damp proofing element projecting from and integral with the wall of the tube intermediate the ends of the tube, in a position such that it will lie in the cavity when the ventulator is fitted in a cavity wall.

Preferably the inlet end of the ventilator comprises an extension of the tube turning the passage through the ventilator through a right angle from the main, wallpenetrating, portion to an inlet opening. The inlet opening may be protected by a grid, which may be formed integral with the inlet extension.

The rigid damp proofing element preferably comprises a flange extending substantially at right angles from the main portion of the ventilator tube and in a preferred construction it takes the form of a box-like element. If the outlet end of the ventilator is open and the damp proof element in the form of a box-like element opening on the inside into the main tubular portion, then the ventilator can also function as an anchoring socket of the kind referred to in the first and second aspects of the invention. Thus, this preferred construction provides various advantages of the anchoring socket in combination with a ventilator capability.

Where a ventilator crosses a cavity in a wall, the conventional damp-proofing technique is to provide a damp proof cavity tray built into the two leaves of the wall and sloping downwardly from the inner leaf to the outer leaf. It is known to provide an upstanding damp proof sheet on a ventilator, but such a sheet could bend under climatic changes or due to poor fitting and actually bridge the cavity in a manner to allow water on the inside face of the outer leaf towards the inner leaf. The rigid damp proofing element provided by the box-like structure is not subject to such defects.

In a preferred construction, a combined anchoring socket and ventilator comprises a main tubular section, open at both ends, one of which constitutes both a ventilator outlet and a lateral restraint strap inlet; a box-like retaining portion extending at right angles from the main tubular section and opening on the inside into that section, the arrangement permitting the hooked portion of a lateral restraint strap to enter the main section through the inlet with the length of the hook por-tion extending widthwise of the main section, and further permitting the hook portion, when aligned with the retaining portion of the socket, to be turned, so that it extends into the retaining portion wherein it can be brought into engagement with the wall of that portion nearest to the inlet, and the ventilation section in the form of a telescopic extension of the main section at the end of the main section opposite to the strap inlet, the ventilator section forming a continuation of the main tube turned through a right angle to a ventilator inlet end.

According to a fourth aspect of the invention a structural assembly comprises a cavity wall having an outer leaf and an inner leaf with a cavity between them and a ventilator built into the wall, the ventilator comprising a main tubular section penetrating both leaves of the wall, with an open outlet in the inner leaf of the wall and an inlet extension projecting on the outside of the outer leaf of the wall, there being an end face of the extension facing in the same direction as the outer face of the wall, and an inlet to the ventilator formed in a face of the inlet extension other than the end face; the ventilator also having a rigid damp proof element projecting from one side of the part of the main tubular section where that section bridges the cavity in the wall, the damp proof element being located within the cavity and serving to arrest flow of moisture across the cavity on the outside of the main tubular section of the ventilator.

Preferably, there is a moisture barrier rib projecting from the outside of the main tubular section of the ventilator on the opposide side of that section to the damp proof element, and within the cavity. Such a moisture barrer rib may extend around all sides of the main tubular section other than that from which the damp proof element projects.

The inlet may be formed in a face of the inlet extension substantially at right angles to the face of the wall and in the preferred construction, it is on either the underside or the top side of the inlet extension. Preferably the inlet opening is protected by a grid.

According to another preferred feature of this aspect of the invention, the main tubular section of the ventilator is telescopic so that its length can be preselected within limits to suit the thickness of the cavity wall in which it is built. One or more mortar keys is or are preferably formedon'the exterior of the main tubular section of the ventilator, and in the preferred construction, these keys are embedded in mortar in both the inner and outer leaves of the cavity wall.

According to a preferred arrangement, the damp proof element is a box-like retaining portion and a lateral restraint strap has its hook portion engaged in this retaining portion, its main straight portion extending out through the open outlet of the ventilator and secured to another structure (e.g. roof structure or floor). This arrangement uses the combined ventilator and anchoring socket version of the third aspect of the invention. It is to be understood that various preferred features of the first and second aspects of the invention can be employed in the third and fourth aspects of the invention.

A very significant advantage of the ventilator in accordance with the invention is that the inlet to the ventilation is nor directly exposed to driving wind, since it is on a face of the ventilator which is not parallel with the outer surface of the cavity wall.

Consequently, it is not necessary to restrict the openings formed in the inlet as is the case with the conventional ventilator brick. The result is that the available ventilation cross section through the inlet is much greater than that of the conventional ventilator brick.

Hence, one can comply with ventilation regulations, using far fewer of the ventilators in accordance with the invention than conventional ventilator bricks, and this is advantageous not only in terms of economy, but also in appearance and strength of the wall.

Generally speaking, the ventilator will be arranged with the inlet on the underside, but in certain conditions, such as under a verge of a roof, the inlet may face upwardly.

According to a fifth aspect of the invention a wall tie for use in building construction comprises a pair of arms joined together at their proximal ends with a hook portion at the distal end of each arm, the arms being able to flex towards each other against resilient load and there being a mortar key at or secured to the proximal ends of the arms, In the preferred construction, the wall tie is made of wire or of rod-like plastics material. Preferably it is made of a single wire or rod-like material, bent to give it the required configuration.

According to a preferred arrangement the mortar key and resilient load are both provided by forming at least one complete loop of the wire or rod at the proximal ends of the two arms.

A wall tie in accordance with this fifth aspect of the invention is useful with an anchoring socket of any of the other aspects of the invention, and if it is to be used with such an anchoring socket, it is constructed so that in their free (splayed apart) condition, the arms at their widest location, are wider than the internal width of the entry portion of the anchoring socket.

The tie can be fitted into the socket by pressing the arms towards each other, against their resilient loading, to an extent which will allow the hooked ends of the arms to pasts through the entry portion in the orientation where the hook portions are widthwise of the entry portion'; the tie is then turned about its own longitudinal axis when the ho9k portions are aligned with the retaining portion of the anchorising socket, to bring the hook portions into the retaining portion of the socket, and then pressure on the arms is relaxed to allow them to spring apart into frictional engagement with the ends of the retaining portion. When so fitted, the loop at the junction of the arms projects out of the socket and can be used as a martar key embedding it in mortar in a secondary wall.

Two inserts for use in walls, one being an anchoring socket and the other a combined anchoring socket and ventilator, and a special wall tie, and their methods of use, will now be described to exemplify the invention, with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of an anchoring socket, Figure 2 is a perspective view showing a section through a cavity wall with a lateral retaining strap and an anchoring socket, Figure 3 is a view similar to Figure 2, but showing an alternative arrangement of the lateral retaining strap and anchoring socket, Figure 4 is another view similar to Figure 2, but showing another arrangement of the retaining strap and anchoring socket, Figure 5 is a perspective view of a combined anchoring socket and ventilator with one end wall removed to show the interior, Figure 6 is a perspective view showing a section through a cavity wall with a combined anchoring socket and ventilator in position, Figure 7 is a view similar to Figure 6,..but showing an alternative arrangement of the anchoring socket~, Figure 8 is a perspective view showing a section through a cavity wall at the verge of a pitch roof, Figure 9 is a perspective view showing a section through a cavity wall in which is fitted a combined anchoring socket and ventilator adjacent to an internal floor, Figure 10 is a perspective view showing the junction between a cavity wall and a wall built at right angles to it, Figure 11 is a section through a cavity wall with a secondary wall made of blocks built at right angles to it, Figure 12 is a section similar to Figure 11, where the secondary wall is made of bricks, Figure 13 is a pan view of a special wall tie, Figure 14 is an elevation of wall tie shown in Figure 13, and Figure 15 is a sectional plan view of a cavity wall with a block secondary wall joined to it by a wall tie as shown in Figures 13 and 14.

In Figure 1, there is illustrated the basic anchoring socket type insert, which has no other function than to receive a lateral restraint strap.

The socket is made from two plastics injection mouldings, namely, a body unit 10 and an end unit 12. It will be seen that the body unit is hollow and of generally rectangular cross section. The end not visible in Figure 1 is closed and the end unit 12 can be welded on to the open end to produce a rectangular box-like structure. Since the socket is to be secured in one of the leaves of a cavity wall, where part of it could be exposed to moisture, it is formed in unsaturated polyvinylchloride of the type now commonly used for window frames and sub frames.This material is moisture resistant and water impermeable and should endure at least as long as other features from which the wall in which it is fitted are made, It will be observed that the completed socket essentially comprises a hollow horizontal top portion 14, which will be referred to as the entry portion, and a hollow vertical portion 16, which will be referred to as the retaining portion, depending from the outer end of the entry portion. The interiors of these two portions are in communication, and the only access to the interior of the sockets is through an opening 18 at one end of the entry portion, this opening being referred to as the inlet. Further, it will be observed that the retaining portion 16 is at one side only of the entry portion, so that the complete socket is L-shaped.

The internal dimensions of the anchoring socket are important. The socket is intended to be used with a standard L-shaped lateral restraint strap, an example of- which appears at 30 in Figure 2. Such a strap is made of galvanized steel, and typically has a width of 30 millimetres and a thickness of 5 millimetres. It has a straight main portion 22 which may be up to 1 metre in length, formed with a series of fixing holes 24, and a hook portion 26, imperforate and bent at right angles to the main portion 22. Typically also, the length of the hook portion will be about 100 millimetres.

The width of the opening 18 (and therefore the internal width of the socket) will be slightly greater then the length of the hook portion 26 of the strap with which the socket is expected to be used. For instance, if the hook portion 26 is 100 millimetres long, then the internal width of the inlet 18 may be 120 millimetres.

The depth of the inlet 18 should be several times the thickness of the strap 20 so that it may for example be 50 millimetres. It will be noted that the thickness of the interior 28 of the retaining portion is considerably less than that of the entry portion - it may for example be only 20 millimetres. Another significant feature of the internal shape of the socket is that the inside corner 30 is rounded or chamfered.

Externally, the entry portion 14 has two mortar key ribs 32 and 34 projecting upwardly from its top surface and two similar ribs 36 and 38 projecting downwardly from its bottom surface. Also, the outer wall 37 of the socket, that is to say the wall opposite the inlet 18, extends outwardly a short distance all round the remainder of the retaining portion 16 to provide drip lips on that portion of the socket.

Á flexible plastics bag (not shown) is permanently attached to the socket near to the inlet 18, by means of a flexible cord. The bag is filled with rockwool fire resistant material and is of such a size that when stuffed in the entry portion 14, through the inlet 18, it substantially fills the entire section of the entry portion.

A locating button 41 is formed integrally with the outer wall 37 and projects outwardly from that wall.

The distance between the tip of the button 41 and the inside face of the wall 39 is equal to the width of the cavity of the wall with which the socket is intended to be used. Whilst the provision of such a button can facilitate fitting the socket, it does also have the effect of adapting the socket for a particular cavity size.

One way of using a socket shown in Figure 11 will now be described with reference to Figure 2. Part of the outer leaf 40 of a cavity wall of a building is shown, together with an inner leaf 42 made of breeze blocks or the like, there being the usual cavity 44 between these leaves. When the block 46 has been laid, it is decided that a lateral restraint strap 20 is required at a height just above the top of the block 46. The bricklayer therefore butters the top of the block 46 with mortar, takes a plastics anchoring socket of the kind described with reference to Figure 1 and lays the entry portion 14 of the socket on the mortar, pressing the ribs 36 and 38 into the mortar, whilst at the same time pulling the inner wall 39 of the retaining portion 16 (which is in the cavity 44) into engagement with the outwardly facing surface of the block 46.In practice, this is not a very skilled operation; it is simply a matter of pressing the socket onto the corner location between the outside and top faces of the block 46, but taking care to press the ribs 36 and 38 as near vertically as possible into'the mortar. If the socket is provided with a location button,then that button will engage with the cavity face of the outer leaf 40 of the wall and the face 39 will automatically be pressed against the cavity face of the inner leaf 42.

After the roof trusses have been fitted, the pike (upper part) of the end wall is built up and the bricklayer builds in the sockets 10. The carpenter will fit a nogging between the two outer trusses at a location where its bottom face is aligned with the entry portion of a socket 10 in the end wall.

The strap 20 is then taken, and held so that its hook portion 26 is horizontal and in alignment with the inlet 18 (the width of the strap will then be in a vertical plane). It is then possible to push the hooked portion of the strap into the entry portion 14 until the hooked portion engages with the inside of the wall 37 when it is aligned with the top end of the interior of the retaining portion 16 of the socket. Then the strap is turned about the longitudinal axis of its main portion through 90 degrees to bring the strap into the operative orientation shown in Figure 2. This has the effect of causing the hooked portion 26 to extend down into the retaining portion 16. The carpenter then pulls the strap to press the hooked portion 26 into engagement with the inside of the wall 39, and then nails the main portion 22 of the strap to the underside of the nogging and rafters.This is the correct location for the lateral restraint strap in accordance with current building regulations. It will be observed, that the restraint strap is quite effective, because the wall 39 of the socket 10 is sandwiched between the hooked portion 26 of the strap and the block 46 of the inner leaf of the wall, so that the strap has the same hooking effect on the inner leaf, as it would have if no socket were provided.

Some of the advantages of the construction illustrtaed in Figure 2 are immediately apparent. To begin with, there is no necessity for co-operative working between the different trades on site. Moreover, within the cavity wall, the totally enclosed retaining portion 16 provides an effective moisture barrier in the region of the opening in the inner leaf for the socket, and the drip lips provided all round the wall 37 ensures that any moisture which arrives in the socket in the cavity is not allowed to travel over the horizontal surface of the socket to and through the inner leaf.

Since the retaining portion 16 extends only part of the way across the cavity from the inner leaf (the minimum cavity width is 50 millimetres) it is very unlikely that a mortar bridge can form across the cavity at the socket location. Furthermore, if the flexible bag provided for the purpose is properly stuffed into the entry portion 14 of the socket after the strap 20 has been fitted, there is a complete fire barrier within the socket.

Hence, it is not possible for flames t9 smoke or travel out of or into the cavity through the socket and even if the socket were to melt in heat the passage through the entry portion would be at least very restricted.

Another advantage of the socket is that it provides protection for the part of the lateral restraint strap which is in the wall. This is important because the galvanising on the strap may crack and the most likely position for corrosion is where the strap engages with the wall.

Turning now to Figure 3, there is illustrated a cavity wall comprising an outer leaf 40 and an inner leaf 42 with a cavity 44 between the leaves. An anchoring socket 10 of the type described with reference to Figure 1, is fitted in the inner leaf 42 during its construction, and the arrangement is very similar to that shown in Figure 2, excepting that the retaining portion 16 of the socket projects upwardly from the entry portion 14, and engages behind a block of the inner leaf above the position at which the strap 20 is fitted.

As appears from Figure 3, this arrangement of the socket 10 (which is simply a different orientation of the socket in the wall) is useful where the strap 20 is required at a location near to the top of the entry portion. The effect of this arrangement is exactly the same as-that of the arrangement shown in Figure 2.

Figure 4 illustrtaes a different orientation of an anchoring socket 10, which may be useful, particularly in circumstances, in which the main portion 22 of the lateral retaining strap 20 has to be secured to a vertical edge of an element such as a nogging or roof timber 50 carried on joists 52. In this construction, the socket 10 is arranged with its width in a vertical plane, so that the hooked portion 26 of the strap 20 is turned sideways in the hooking position. The arrangement can be considered to be identical with the arrangements shown in Figures 2 and 3, excepting that the entry portion 14 is secured in a joint between the ends of two building blocks of the inner leaf 42, and the retaining portion 16 is turned sideways from the entry portion instead of projecting downwardly or upwardly therefrom. The effect of the arrangement is exactly the same as that shown in Figure 2.

Figure 5 illustrates a combined anchoring socket and ventilator, in accordance with the invention. The anchoring socket is illustrtaed at 60 and as with the socket 10, it is made from two elements, namely a body unit as illustrated, to which is welded a side plate (not shown). The side plate has been omitted in Figure 5, in order to show the internal structure of the anchoring socket. A ventilator unit 62 is also provided, and this unit also has a central unit as illustrated, with a welded on end plate (not shown).

Both the anchoring socket and the ventilator unit are made in moulded unsaturated polyvinylchloride, in similar fashion to the socket 10 illustrtaed in Figure 1.

The socket 60 has a main rectangular cross section tubular portion 62 which is open at both ends. It also has a vertically upstanding box-like retaining portion 66, which is very similar in all respects to the retaining portion 16 illustrated in Figure 1. In fact, the socket 60 differs from the socket 10 mainly in the provision of a continuation of the entry portion beyond the retaining portion, to constitute the main tubular portion 62.

It will be observed that T cross section mortar anchoring ribs 68 and 70 are formed respectively on the outsides of the top and bottom walls of the main tubular portion 64. The open end 27 of the main tubular portion provides a restraint strap inlet, but in this construction, it also functions as a ventilator outlet as will hereinafter appear. It is desirable to provide a cavity location button similar to the button 41 (see Figure 1) on the inner face of the retaining socket 92.

It this is not practicable a smali cavity spacing rib may be provided in the angle between the inner face of the socket 92 and the top face of the tubular portion 64, this rib extending from the socket 92 by the same distance as a cavity spacing button.

The ventilator unit 62 has a straight rectangular cross section tubular portion 74 which is a telescopic sliding fit in the outer end of the main tubular portion 64, but the outer end of the ventilator unit 62 comprises an angled extension 76 having a closed end wall 78, which is curved for streamline flow purposes, and is open on the underside at 80. A series of ribs 82 across the open underside of the extension 76 provide a grid and the open underside forms the inlet of the. ventilator.It is an -important feature of this construction, that the ventilator inlet 80 is in a wall of the extension 76 other than the end wall which closes the end of the main tubular portion of the device, and indeed this ventilator inlet opens in a face of the extension 76 which is parallel with the top and bottom walls of the main tubular portion of the ventilator.

The ventilator unit 62 is provided with mortar engaging ribs 84 and 86 extending from its top and bottom surfaces near to the outer end, and the outer end of the socket main tubular portion 64 terminates in L-shaped mortar engaging ribs 88 and 90 on the top and bottom sides respectively. Within the main tubular portion 64 the outer wall 92 of the retaining portion 66 has a short extension 94, and an upstanding rib 96 on the inside of the opposite wall of the main tubular portion is aligned with this extension rib 94.

A construction in which the combined unit illustrated in Figure 5 is employed in a building is illustrated in Figure 6. Part of the outer leaf of a cavity wall is shown at 100, there being an inner leaf 102 with the usual cavity 104 between them.

At a position where a lateral restraint strap 20 is required and ventilation is also required to the inside of the wall, mortar 106 is buttered on the tpp surfaces of substantially in line courses of the bricks and blocks of the two leaves of the wall, and then a combined unit as illustrated in Figure 5 is embedded in this mortar, so that the unit extends completely through the cavity wall. The angled extension 76 is on the outside of the wall, and the ventilator unit 62 is pushed inwardly as permitted by the telescopic arrangement of the element, until the inside face 81 (see Figure 5) between the angled end portion 76 and the straight portion 74 engage with the mortar or the outer surface of the outer leaf 100. In this position, only the extension 76 of the unit is visible on the outside of the wall, and the inlet 80 is on the underside of this extension.

As with previously described arrangements, the retaining portion 66 is located in the cavity, and in the construction illustrated in Figure 6, it is in engagement with the outwardly facing surface of the inner leaf 102.

The strap 20 is fitted as previously described into the socket provided by the combined unit. but it will be mentioned that the ribs 94 and 96 (see Figure 5) are useful in providing stops against which the hooked portion of the. strap can engage during fitting, to indicate that the hooked portion is in alignment with the retaining portion 66. This is necessary, because of the straight through tubular portion 64, which does not in itself provide a means of indicating when the hooked portion of the lateral restraint strap is in alignment with the retaining section 66.

It will be seen from Figure 6, that in addition to providing the.socket for the strap 20, the unit when fitted, provides very adequate ventilation from the outside to the inside of the cavity wall. Furthermore, the inlet 80 is protected from the elements, by the turned down extension 76 of, the unit, and consequently, the grid formed by the ribs 82 can be arranged to provide a minimal obstruction to air flow through the inlet. In other words, almost the total cross sectional area of the inlet - which corresponds to the cross sectional area of the main tubular portion 64 - is available for air flow. This of course is a great advantage over conventional ventilation bricks.

In addition, the combined unit illustrated in Figure 6 provides the advantages of the anchoring socket for a lateral restraint strap.

The orientation of the combined ventilator and socket shown in Figure 6 i.e. with the retaining portion 66 projecting upwards from the main tubular portion 64, should be adopted in all cases except where the unit is fitted adjacent to the roof rafters. This is because mortar droppings resting on the part of the main tubular portion 64 which is in the cavity 104, could form a bridge for moisture across the cavity, but for the damp proof course provided by the upstanding retaining portion 66. Since the retaining portion 66 is of very rigid box-like form it is unlikely to deform despite temperature changes or if t is accidentically struck by falling mortar or the like; hence, it maintins a damp proof barrier across the cavity above the tubular portion 64.

Turning now to Figure 7, there is illustrated an arrangement very similar to that shown in Figure 6, and consequently the same reference numerals have been used. In fact, the only difference is that the orientation of the socket section of the unit is different, in that the retaining portion 66 depends from the main tubular portion 64, and engages behind the block of the inner leaf 102 beneath the ventilator position. This location for the anchoring socket is the same as that illustrated in Figure 2, and it is used where the unit is mounted in the cavity wall adjacent to the rafters. In that location the downward projection of the retaining portion 66 is essential if a lateral restraint strap is to be used, because the portion 66 must engage with an uncut block.However, the damp proofing effect of the portion 66 is less important, because no mortar will drop on to the main tubular portion 66, since there are no full courses of blocks above the unit at that level.

It will be noted that the inlet 80 is still on the underside of the extension 76 which is on the outside of the outer leaf of the wall. This can be achieved, because the ventilation unit 62 can be completely removed from the main tubular portion 64 of the socket unit and replaced in an inverted position, i.e. with the downturned extension 76 extending generally in the same direction as the retaining portion 66.

Figure 8 illustrates an arrangement in a building having a cavity wall comprising an outer leaf 110 and an inner leaf 12 with a cavity 114 between them, the wall supporting proof 116. There is a verge 118 which overhangs the wall 110, and a barge board 120 depending from the verge 118 and providing a weather protection for the area just under the verge.

In this construction, it is required to provide ventilation into the space immediately underneath the roof 116, and this is achieved, by utilising a combined anchoring socket and ventilator unit of the type shown in Figure 5, fastened in the wall 110, 112, in the similar arrangement to that shown in Figure 7 (i.e. with the retaining portion 66 depending into the cavity 114) but in this construction, the ventilator unit 62 is positioned in the main tubular portion 64 in such a manner, that the inlet 80 is uppermost.

This orientation is possible, because of the weather protection for the ventilator inlet provided by the verge 118 and barg board 120.

The construction which is illustrated in Figure 9 shows how a combined unit of the kind described above with reference to Figure 5, can be used in the cavity wall of a building underneath the horizontal damp nroof course, which is provided between the external ground level and the internal floor level. Part of the outer leaf of a cavity wall is shown at 130, the inner leaf being illustrated at 132, with the cavity 134 between them. A paved area external to the building is illustrated at 136, and 140 shows the internal tongued .

and grooved timber floor. The conventional horizontal damp proof course is provided in both leaves of the wall at 138 at a position just below the level of the internal floor 140, and it will be noted that there are three courses of bricks in the outer leaf 130 of the wall between the outside ground level as represented by the paving 136 and the horizontal damp proof course 138. The ventilation for the under floor space has to be provided through this portion of the cavity wall.

As illustrated in Figure 9, a unit such as that described above with reference to Figure 5 is fitted on top of the two bottom courses in the outer leaf 130 and on top of the bottom single course of blocks in the inner leaf 132. The orientation of the anchor socket is such that the retaining portion 66 projects upwardly into the cavity 134 above the damp proof course 138, and the arrangement of the ventilation unit 62 is such that the inlet end faces downwardly.

In this construction, no lateral restraint straps are employed, and the combined unit functions simply as a ventilator, although the retaining portion 66 also provides a vertical damp proof membrane above the ventilator. Because the inlet 80 faces downwardly, it is protected from driving winds,.and it is extremely unlikely that rainwater will be driven through this inlet into the main tubular portion 64 of the combined unit. Even if it is however, there is a moisture barrier presented by the upstanding rib 96 which will resist flow of water through the ventilator into the under floor space.

As has already been mentioned, the invention can be used for the, joining together of two walls arranged at right angles to 'each'other. This situation frequently arises in building construction, and is illustrated in Figure 10, wherein there is a cavity wall comprising an external leaf 140 and an internal leaf 142, with an internal single leaf dividing wall 146 disposed at right angles to and abutting the internal leaf 142.

For various reasons, it is often not practicable to build up the dividing wall 146 at the same time as the main cavity wall is being constructed, and provision has to be made for keying the dividing wall 146 to the cavity wall. There are two ways of doing this, viz: Holes can be left in the internal leaf 142 during its construction, to allow blocks or part blocks from the dividing wall 146 to project into those holes to provide proper keying. In practice, this is not altogether satisfactory, because it is very difficult to create proper mortar joints in the blocks or part blocks which are inset into the cavity wall, and there is a considerable danger that mortar will be pushed into the cavity, and since the openings are vertically above each other, this can create a piie of mortar in the cavity which can bridge the cavity above the damp proof course.The second method is to build conventional butterfly wall ties into the inner leaf 142 leaving part of each wall tie projecting from the cavity wall for building into the horizontal mortar courses of the dividing wall 146.

This is not very satisfactory, because the butterfly type wall ties are not in themselves well adapted to prevent lateral motion of the dividing wall 146 relatively to the cavity wall.

In the construction in accordance with the invention, whilst the cavity wall is being built up, anchoring sockets 10, similar to those described with reference to Figure 1, are built into the inner leaf as illustrated.

Then, as the dividing wall 146 is being built up, lateral restraint straps 20 are fitted into each of the -sockets 10 and engaged in the horizontal mortar courses of the dividing wall 146. Since the main portions of the straps become firmly embedded in the dividing wall, there is a strong connection between the cavity wall and the dividing wall.

It will be appreciated, that the construction illustrated in Figure 10 can be used, where the wall 146 is an external wall.

Figure 11 shows the construction illustrated in Figure 10 in section and Figure 12 illustrates an alternative construction in which the wall 146 is made of conventional building bricks rather than breeze blocks.

The special form of wall tie which is illustrated in Figures 13 and 14 can be used with an anchoring socket 10 of the type described previously, where it is required to secure a secondary wall to the cavity wall in which the socket is built.

The tie 160 is made from a long thin strip of plastics material, or from a piece of spring steel wire, galvanized or plastics coated. Beginning from one end, the wire or strip is bent to form a wall retaining hook o Sportion 162; an arm 164; a- 540 loop 166; an arm 168 similar to the arm 164, and a hooked portion at the distal end of the arm 168 identical with the hook o portion 162. The 540 loop 166 forms a complete circle at the proximal ends of the arms 164 and 168, and it will be observed from Figure 13, that these arms are splayed apart somewhat from the proximal towards the distal ends.

The hook portions 162 are of approximately the same length as the hook portions 26 described with reference to Figure 2, and the overall width between the distal ends of the arms 164 and 168 is slightly wider than the internal width of an anchoring socket 10.

A method of using a tie such as that illustrated in Figures 13 and 14 is illustrated in Figure 15. A cavity wall comprises an external leaf 170 and an internal leaf 172 with a cavity 174 between them. An anchoring socket 10 is illustrated diagrammatically, overlying one of the blocks of the external leaf 170.

The secondary wall is shown at 176 and it extends at right angles to the outer face of the external leaf 170.

This diagram also shows the use of a button 178 on the outside of the retaining portion 16 of the socket 10 for determining the location of the socket in the wall.

In order to fit the tie 160, the tie is turned so that the hook portions 162 lie horizontally, and the arms 164 and 168 are pressed together manually against the resilient loading provided by the loop 166, until they are sufficentlS close together to enable the hook portions 162 to be slid into the inlet end of the entry portion 14. When the hooked ends of the arms'164 abut the outer wall of theret-aining portion 16, the tie 160 is turned about its own longitudinal axis through 900, in order to bring the hook portions 162 into the space within the retaining portion 16 of the socket, and into engagement with the wall 39 of the socket.Pressure on the arms of the tie is then released, and this allows the arms to spring outwardly, into the position illustrated in Figure 15, wherein they engage frictionall against the inside faces of the retaining portion of the socket. Because the tie is wider in its free condition than the internal width of the socket, it will remain in this frictional engagement with the inside walls of the socket, and this helps to retain the tie in position. However, the bricklayer should also push mortar into the entry portion of the socket, to fill the socket as far as practicable and this mortar secures the tie in the socket.

A tie is fitted at each end of the socket positions, leaving the looped end of the tie projecting from the cavity wall, for building into the horizontal courses of the secondary wall 176. It will be appreciated that the looped end 166 provides a particularly efficient mortar key as well as providing the resilient loading for the tie itself.

Claims

CLAIMS:

1. An anchoring socket intended to be built into the wall of a building, for receiving an angled retaining strap used to secure the wall to another structure, comprising a box-like entry portion adapted to be built into the structural elements of a wall and having an other opening which in use is on the inside of the wall, and a box-like retaining portion disposed at right angles to the entry portion and adapted in use to rest against an outwardly facing surface of the wall, so that: the wall engaging part of an angled retaining strap can be introduced into the anchoring socket through the opening in the entry portion when the said wall engaging part extends width-wise of the entry portion; when the wall engaging part is aligned with the retaining portion, the retaining strap can then be turned to bring the wall engaging--part into the retaining portion and wherein it can be drawn into engagement with the outwardly facing inside face of the retaining portion.

2. An anchoring socket as claimed in Claim 1, which is provided with one or more mortar keys projecting outwardly from the entry portion.

3. An anchoring socket as claimed in Claim 2, in which the mortar key comprises a rib extending laterally of the entry portion.

4. An anchoring socket as claimed in Claim 3, in which there are mortar ribs on both the top and bottom sides of the entry portion.

5. An anchoring socket as claimed in any one of Claims l to 4, in which the socket is provided with a cavity spacer projecting outwardly for engagement with the inwardly facing surface of the outer leaf of a cavity wall when the retaining portion is located in the cavity.

6. An anchoring socket as claimed in any one of Claims 1 to 5, in which the retaining portion has a lip or flange projecting outwardly all round the periphery of the retaining portion to form a moisture strip irrespective of the orientation of the socket in the wall.

7. An anchoring socket as clai--,ned in Claim 6, in which the lip forms a continuation of that wall of the retaining portion which closes the outer end of the inlet portion.

8. An. anchoring socket as claimed in any one of Claims 1 to 7, in which the internal corner between the entry portion and the retaining portion is rounded or chamfered to ensure engagement of the wall engaging portion of the lateral restraint strap with the internal face of the retaining portion.

9. An anchoring socket as claimed in any one of Claims 1 to 8, which is made in moisture resistant and water-impermeable material.

10. An anchoring socket as claimed in Claim 9, which is made in polyvinylchloride or polyethylene.

11. An anchoring socket as claimed in any one of Claims 1 to 10, which is made from two injection mouldingswelded together.

12. An anchoring socket as claimed in any one of Claims 1 to 10, which is made from an extrusion cut to short lengths and with end plates welded to its open ends.

13. An anchoring socket as claimed in any one of Claims 1 to 12, in which the interior is only open to the inside at the inlet end to the entry portion.

14. An anchoring socket as claimed in any one of Claims 1 to'13, which is provided with a flexible bag filled ith flame-retardant material, this bag being of such size that when stuffed into the entry portion after fitting of the lateral restraint strap, it provides -an effective fire barrier within the socket.

15. An anchoring socket as claimed in Claim 14, in which the bag is attached to the socket by a flexible connection so that it remains with the socket during transport and fitting.

16. A structural assembly comprising an cavity wall having inner and outer leaves with a lateral restraint strap securing at least the inner leaf of the wall to another structural feature, there being an anchoring socket in which a hook portion of the lateral restraint strap in received, the anchoring socket comprising a box-like entry portion built into the inner leaf of the wall and having an opening on the inside of the inner leaf, and a box-like retaining portion in internal communication with the interior of the entry portion, the retaining portion lying within the cavity, and in engagement with the outwardly facing surface of the inner leaf, the hook portion of the lateral restraint strap lying within the retaining portion of the anchoring socket and in engagement with the inside of-the wall of the retaining portion which engages with the.inner leaf of the wall, the main section of the lateral restraint strap extending through the entry portion of the anchoring socket and out through the opening in the entry portion.

17. A structural assembly as claimed in Claim 16, in which the width of the entry portion exceeds the length of the hook portion of the lateral ret---:aint strap and the depth of the entry portion exceeds the width of the hook portion.

18. A structural assembly as claimed in Claim 16 or Claim 17, in which the retaining portion does not extend more than half way across the width of the cavity.

19. A structural assembly as claimed in any one of Claims 16, 17 and 18 in which the anchoring socket is constructed as claimed in any one of Claims 1 to 15.

20. A ventilator for use in a cavity wall of a building comprising a tube, having an inlet at one end and an outlet at the other end, the inlet being formed in a surface which does not face directly outwards from the end of the tube, and a rigid damp proofing element projecting from and integral with the wall of the tube intermediate the ends of the tube, in a position such that it will lie in the cavity when the ventilator is fitted in a cavity wall.

21. A ventilator as claimed in Claim 20 in which the inlet end of the ventilator comprises an extension of the tube turning the passage through the ventilator through a right angle from the main, wall penetrating, portion to an inlet opening.

22. A ventilator as claimed in Claim 21, in which the inlet opening is protect,sd -by a grid".

23. A ventilator as claimed in Claim 22, in which the grid is formed integral with the inlet extension.

24. A ventilator as claimed in any one of Claims 20 to 23, in which the rigid damp-proofing element comprises a flange extending substantially at right angles from-the main portion of the ventilator tube.

25. A ventilator as claimed in Claim 24, in which the rigid damp-proofing element takes the form of a box-like element.

26. A combined anchoring socket and ventilator comprising a main tubular section, open at both ends, one of which constitutes both a ventilator outlet and a lateral restrain strap inlet; a box-like retaining portion extending at right -angles from the main tubular section and opening on the inside into that section, the arrangement permitting the hooked portion of a lateral restraint strap to enter the main section through the inlet with the length of the hooked portion extending widthwise of the main section, and further permitting the hooked portion, when aligned with the retaining portion of the socket, to be turned, so that it extends into the retaining portion wherein it can be brought into engagement with the wall of that portion nearest to the inlet, and a ventilation section in the form of a telescopic extension 'of' the main.-section' at the end of the main section opposite to the strap inlet, the ventilator section forming a continuation of the main tube turned through a right angle to the ventilator inlet end.

27. A structural assembly comprising a cavity wall having an outer leaf and an inner leaf with a cavity between them and a ventilator built into the wall, the ventilator comprising a main tubular section penetrating both leaves of the wall, with an open outlet in the inner leaf of the wall and an inlet extension projecting on the outside of the outer leaf of the wall, there being an end face of the extension facing in the same direction as the outer face of the wall, and an inlet to the ventilator formed in a face of the inlet extension other than the end face; the ventilator also having a rigid damp-proof element projecting from one side of the part of the main tubular section where that section bridges the cavity in the wall, the damp-proof element being located within the cavity and serving to arrest flow of moisture across the cavity on the outside of the main tubular section of the ventilator.

28. A structural assembly as claimed in Claim 27, in which there is a moisture barrier rib projecting from the outside of the main tubular section of the ventilator on the opposite side of 'that section to the damp-proof element, and within the cavity.

29. A structural assembly as claimed in Claim 28, in which the moisture barrier rib extends around all sides of the main tubular section other than that from which the damp-proof element projects.

30. A structural assembly as claimed in any one of Claims 27 to 29, in which the inlet is formed in a face of the inlet extension substantially at right angles to the face of the wall.

31. A structural assembly as claimed in Claim 30, in which the inlet is on either the underside or the top side of the inlet extension.

32. A structural assembly às claimed in any one of Claims 27 to 31, in which the inlet opening is protected by a grid.

33. A structural assembly as claimed in any one of Claims 27 to 32, in which the main tubular section of the ventilator is telescopic so that its length can be preselected within limits to suit the thickness of the cavity wall in which it is built.

34. A structural assembly as claimed in any one of Claims 27 to 33, in which one or more mortar keys is or are formed on the exterior of the main tubular section of the ventilator.

35. A ; structural assembly as claimed in Claim 34, in which the keys are embedded in mortar in both the inner and outer leaves of the cavity wall.

36. A structural assembly as claimed in any one of Claims 27 to 35, in which the damp-proof element is a box-like retaining portion and a lateral restraint strap has its hook portion engaged in this retaining portion, its main straight portion extending out through the open outlet of the ventilator and being secured to another structure.

37. A wall tie for use in building construction comprising a pair of arms joined together at the-ir proximal ends with a hook portion at the distal end of each arm, the arms being able-to flex towards each other against resilient load and there being a mortar key at or secured to the proximal ends of the arms.

38. A wall tie as claimed in Claim 37, which is made of wire or of rod-like plastics material.

39. A wall tie as claimed in Claim 38, which is made of a single wire or rod-like material, bent to give it the required configuration.

40. A wall tie as claimed in Claim 38 or Claim 39, in which the mortar key and resilient load are both provided by forming at least one complete loop of the wire or rod at the proximal ends of the two arms.

41. An anchoring socket intended to be built into the wall of a building constructed and arranged substantially as herein described with reference to Figure 1 to 4 of the accompanying drawings.

42. A combined anchoring socket and ventilator constructed and arranged substantially as herein described with reference to Figures 5 to 9 of the accompanying drawings.

43. A wall tie for building construction constructed and arranged substantially as herein described with reference to Figures 13, 14 and 15 of the accompanying drawings.

44. A structural assembly substantially as herein described with reference to any one of figures 2, 3, 4, 6, 7, 8, 9, 10 or 11 and 12 of the accompanying drawings.