GB2109835A

GB2109835A - Cavity-wall ties and frame ties

Info

Publication number: GB2109835A
Application number: GB08134356A
Authority: GB
Inventors: David Lawrence Courtney; William Terence Bacon
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-11-13
Filing date: 1981-11-13
Publication date: 1983-06-08

Abstract

A reversible cavity wall tie 1 (Figs. 1, 2, and 3) has two coplanar flat end portions 2, 3 and a tilted central portion (6) which is connected to the end portions by side walls (7, 8). The tilted portion sheds any mortar droppings. The distance (B) between the side walls provides automatic cavity width adjustment. The tie may be made of a non-corrodable plastics. A reversible frame tie 20 (Figs. 4 and 5), which may be made of a plastics material, has one end 26 shaped for interlocking engagement with a frame. The other end may have aperture 25 for secure fixing in mortar. <IMAGE>

Description

SPECIFICATION Building ties This invention relates to ties for use in the building industry and, in particular, to cavity wall ties and frame ties.

Ties are employed during the construction of a cavity wall to bond the two leaves of the wall together. The ties are generally elongate and extend across the cavity with opposite ends embedded in mortar bonding the bricks or blocks of the wall. Various shapes of tie are known and they are generally made from gaivanised iron or stainless steel. One known design of cavity wall tie is formed from a strip of metal. It is twisted to provide a central portion which is vertical in use and acts as a water drip member, thus preventing water traverse between the wall leaves across the tie. The ends of the tie are split to facilitate bonding with the mortar. This form of tie is reversible, that is it can be used with either of two substantially flat faces uppermost and the central portion vertical, and thus employment by a bricklayer is facilitated.Another known form of cavity wall tie is formed into a figure 8 or butterfly configuration from a length of wire. The ends of the wire are twisted together at the centre of the configuration and point in a direction perpendicular to the plane of the configuration.

This twisted together portion serves as a water drip member but since it must be directed downwards in use this form of wall tie is not reversible. An alternative wire wall tie has triangularly formed ends for embedding in mortar and a central straight portion which incorporates a deformation acting as a water drip member.

Galvanised iron ties may suffer from corrosion after incorporation in a building and subsequently fail, with the result that the wall leaves are no longer bonded together. Stainless steel ties whilst overcoming the corrosion problem have the disadvantage of being considerably more expensive than galvanised iron ties.

A known wall construction technique involves a cavity wall comprising an inner frame of, for example, timber, and an outer brick or block wall.

It is also necessary to tie these two wall leaves together and this is conventionally achieved by securing one end of a wall tie to the frame by nailing or screwing, whilst the other end is embedded in the mortar bonding the blocks or bricks of the wall.

Ties are also employed to secure frames, such as door or window frames, to surrounding brick or block walls. Conventionally the tie is fixed at one end to the frame by nailing or screwing and the remainder of the tie is embedded in the mortar bonding the bricks or blocks together. During construction a frame is supported in position and the brickwork built up around it, ties being inserted at suitable spacings to secure the frame and wall together. The act of nailing, in particular, a tie to the frame tends to result in displacement of the frame from the desired position, or twisting of the frame, with resultant problems of door or window fit in the frame.

According to one aspect of the present invention there is provided a tie, for interconnecting two members, comprising an elongate elements with substantially flat strip-like end portions, the end portions being arranged in a common plane and adapted for securement to a respective one of the members, and a central portion, between and connected to the end portions, tilted out of the common plane and extending at an angle to the longitudinal axis of the element.

According to another aspect of the present invention there is provided a tie, for securing a frame member to a wall member, comprising an elongate strip-like element whose end portions are adapted for securement to a respective one of the frame and wall members, and wherein the end portion for securement to the frame member is adapted for interlocking engagement therewith.

According to a further aspect of the present invention there is provided a tie in combination with a frame member, which frame member is to be secured to a wall member by means of the tie in use of the combination, wherein the tie comprises an elongate strip-like element having one end of a shape adapted for interlocking engagement with a corresponding slot or aperture of the frame member, and wherein the other tie end is adapted to be secured in mortar of the wall member in use of the combination.

Embodiments of the present invention will now be described with reference to the accompanying drawings, in which Fig. 1 is a plan view of an embodiment of cavity wall tie; Fig. 2 is a side view of the embodiment of Fig.

1; Fig. 3 is a section taken along line Ill-Ill of Fig.

2; Fig. 4 is a partly-sectional view of an embodiment of frame tie bonding a frame and a wall together; Fig. 5 is a sectional side view of the arrangement of Fig. 4; Fig. 6 is a partly-sectional plan view of an embodiment of tie for bonding a timber frame to a brick wall, and Fig. 7 is a plan view of another embodiment of timber frame/brick wall tie interlocking with a timber frame.

The cavity wall tie 1 shown in Figs. 1 to 3 is an elongate element with substantially flat strip-like end portions or fixing lugs 2 and 3, which have respective apertures 4 and 5, and a central portion 6. As can be appreciated from Fig. 3 in particular, the central portion 6 is tilted at an angle A to the plane of the end portions 2 and 3 about the longitudinal axis of the element and is joined to the end portions by end wall portions 7 and 8 which are substantially perpendicular to the plane of the end portions 2 and 3, to the central portion 6 and to the longitudinal axis of the element. The distance between the outermost faces of the wall portions 7 or 8 along the longitudinal axis is B, which can be the desired cavity width. The tie is reversible, that is it can be used either way up.

When tie 1 is incorporated in a cavity wall, as indicated by the dotted brickwork lines in Fig. 2, the tie is securely fixed by virtue of mortar employed between the bricks surrounding the lugs 2 and 3 and penetrating the apertures 4 and 5. The central portion 6 provides automatic cavity width adjustment if the brickwork is set in contact with the end wall portions 7 and 8.

The angle nature of the central portion 6 also provides that droppings of mortar, cement or other materials employed in the construction of the wall, will tend to slide off the central portion and thus cleaning of the tie is facilitated. Such cleaning is necessary in order to prevent the formation of a bridge via which moisture may travel from one wall leaf to the other. In addition, the angled nature of the central portion provides that water cannot readily flow between the wall leafs over the tie itself, since the angle will tend to direct water into the cavity. In order to even more reliably prevent such water traverse, the central section 6 may be grooved over its entire circumference and perpendicularly to its length, as indicated in Fig. 1 to 3, to form a drip gully.

Alternatively, a raised wall or bead (not shown) may be provided as a drip member in place of the gully.

The height of the wall portions 7 and 8, and thus the value of angle A, should be such that a sufficient amount of end wall portion area is provided for engagement with the brickwork for cavity width setting and that this is consistent with the overali strength of the tie. Typically A is of the order of 450 whereas larger angles are conceivable, such as up to 900, the strength of the tie would be considerably reduced. Smaller angles would mean smaller end wall portions for contact with the brickwork and reduced cavity width assessment performance, and that droppings would not slide off so readily.

The end portions of fixing lugs 2 and 3 may be shaped otherwise than as shown in Figs. 1 and 2.

For example, the apertures 4 and 5 could be omitted and each end split longitudinally to form divergent arms as in a conventional tie with a central vertical twist.

The cavity wall tie of Figs. 1 to 3 and as described above may be made of metal, such as galvanised iron or stainless steel, or alternatively of a non-corrodible material such as a plastics material with characteristics such as to provide a plastics tie with equivalent strength and performance to metal tie and suitable ageing properties. The use of a plastics material would overcome the corrosion problems associated with galvanised iron ties, however, the plastics material must be suitably chosen to withstand any foreseeable substances likely to be subsequently introduced into the cavity, such as foam cavity wall insulation. One material presently considered suitable is polyethylene, and in fact regranulated polythylene may be used, which has the added advantage of low cost.

Several hundred wall ties are commonly employed in the building of a house. The ties are generally supplied in bundles tied with twine, or the like, which the bricklayer cuts with his trowel, thus allowing the ties to fall in a heap. In view of the conditions pertaining at a building site, conventional dark coloured ties can readily be lost in the mud and mire, so that the wastage rate is high. It is considered that plastics ties which are brightly coloured, for example blue, would be more easily seen. Regranulated plastics are generally so coloured and thus distinguished from 'new' material. Thus the wastage rate should be reduced. The tie shape shown in Fig. 1 to 3 is particularly suitable for manufacture by a plastics moulding technique.Whereas the central section 6 of the tie of Figs. 1 to 13 is substantially rectangular in shape with parallel outer edge faces 10 and 11, these edge faces may, alternatively, be shaped differently, for example present a point or a curve. Projectry members may be provided on the end portions 2 and 3, instead of the apertures. For receivement to the mortar.

A frame tie 20 is shown in Figs. 4 and 5 tying a frame member 21 to a wall member comprising bricks or blocks 22 bonded together with mortar or cement 23. The tie 20 comprises elongate, substantially flat, strip-like element with a tail end portion of fixing lug 24 with an aperture 25 to ensure a secure fixing in mortar 23, and a head end portion 26 for interlocking engagement with the frame member 21. In the embodiment shown in Figs. 4 and 5, the head portion is dovetailshaped and attached to the tail portion by a neck portion 27. The head portion 26 is located within the frame, having been inserted thereinto through a slot 28 in the face of the frame which in use adjoins the wall and which extends along substantially the full length of the frame.The slot 28 is of a cross-section consistent with that of the head and neck portions and such as to prevent the head being withdrawn in the orientation shown. The shape of the head and neck portions is such that a tie may be arranged in the slot 28 at any position along its length, by holding the tie such that the head extends towards the slot but at 900 to the orientation shown in Fig. 5, that in rotating it through 900 about its longitudinal axis, inserting the head and neck portions into a slot, and rotating the tie through a further 900 to adopt the position shown in Fig. 4 in which the shoulder portions 29 prevent withdrawal of the tie. Thus the tie and frame are interlocked.

Such a frame tie 20 would be employed as follows. A frame having a suitable slot 28 is supported in the required position relative to a building, or a foundation thereof, and a bricklayer builds up a wall relative thereto. At intervals he inserts frame ties 20 into the slot 28, as described above, and embeds the tail portions thereof in the mortar 23 between the courses of bricks 22. No nailing or screwing is required and thus the frame is not moved from its supported position.

Whereas a dovetail interlocking arrangement has been described, other interlocking shapes such as part-circular or hexagonal are possible.

The criteria for the shape for this type of interlocking being that it should be possible to insert the tie into the slot when the tie is rotated 900 about its longitudinal axis from its in use orientation, and then once inserted rotation through a further 900 to the in-use orientation the head portion is retained in the slot by the shoulders such as 29. A dovetail arrangement without a neck portion may be employed.

The frame ties described above are reversible which facilitates their use, and a frame once tied thereby to a wall cannot easily be separated therefrom; cutting of the tie being necessary. The frame tie may be made of metal or of a suitable plastics material as described above.

Regranulated polythylene is presently preferred.

The frame ties may, for example, be employed with timber frames in which a suitable slot has been machined, or a plastics frame with a suitable slot 28 moulded therein. The slot in the frame will also provide a drainage path for any moisture which penetrates thereto.

The tie 30 shown in Fig. 6 may be used to tie a timber or other internal frame 31 to a conventional block or brick wall 32, leaving a cavity there between. The tie 30 incorporates a dovetail fixing arrangement 33 at one end for interlocking with frame 31 in a manner described above with reference to Figs. 4 and 5. End portion or lug 34 is embedded in the mortar of the wall 32. The cental section includes an angled portion 35 which may or may not be exactly equivalent to the portion 6 of the wall tie Figs. 1 to 3. The angled portion 35 may be provided with a drip gully or wall if required, and may form all or part of a cavity width assessment system.In the embodiment illustrated in Fig. 6, the cavity width would be determined by the position of the end wall portion of the angled section which is adjacent the brickwork when the dovetail portion 33 is correctly engaged in the matching slot 36 provided in the internal frame 31.

The tie 30 may be made of metal or plastics as described above, and as with ties 1 and 20 may be used either way up, which greatly assists the bricklayer. The tie 30 is inserted in slot 36, as described for the insertion of tie 20 in slot 28, are the tail end portion 34 secured in mortar between two courses of bricks.

The tie 40 shown in Fig. 7 is similar to that shown in Fig. 6 except for the head end portion 41, which is provided with gripping means such as a number of projecting barbs or fins which, once the head is pushed into a suitably dimensioned slot or aperture in a frame (not shown), serve to retain the tie interlocked with the frame. Alternatively, for example, the head end may have slots and the frame slot may have projecting fins for interlocking engaging therewith. The tie 40 as a lug portion 42 for embedding in mortar and a central angled portion 43 for preventing moisture traverse, aiding removal of mortar droppings and acting as a cavity width assessment devise. The tie 40 may be made of plastics or metal, as described above with respect to the other embodiments.

The ties 30 and 40 may in fact be considered variants of the tie 1 of Fig. 1 , since they effectively comprise a tie 1 having one section altered to provide interlocking with a member other than a brick wall, for example, a timber frame. The ties 30 and 40 may in fact be used both as brick to brick cavity wall ties and as brick to timber frame cavity wall ties.

The dovetail type of interlocking arrangement shown in Figs. 4 and 5 for a frame tie may be replaced by gripping means such as projecting barbs or fins as described with reference to Fig. 7, with the slot or an aperture in the frame member to be gripped shaped accordingly.

Claims

1. A tie, for interconnecting two members, comprising an elongate element with substantially flat strip-like end portions, the end portions being arranged in a common plane and adapted for securement to a respective one of the members, and a central portion, between and connected to the end portions, tilted out of the common plane and extending at an angle to the longitudinal axis of the element.

2. A tie as claimed in claim 1, wherein the central portion has end walls via which it is connected to the end portions, which end walls are substantially perpendicular to the common plane and to the longitudinal axis of the element.

3. A tie as claimed in claim 1 or claim 2, wherein the central portion extends on opposite sides of the longitudinal axis whereby the tie is reversible.

4. A tie as claimed in anyone of claims 1 to 3 and for interconnecting the two leaves of a cavity wall, wherein around the circumference of the central portion and substantially perpendicular to the longitudinal axis there is provided a drip member to prevent moisture traverse between the two leaves in use of the tie.

5. A tie as claimed in claim 4, wherein one leaf comprises a brick or block wall bonded with mortar, and wherein one end portion is provided with an aperture therethrough to assist keying of the tie in the mortar in use of the tie.

6. A tie as claimed in any one of claims 1 to 4, wherein one end portion is adapted for interlocking engagement with the respective member.

7. A tie as claimed in claim 6, wherein the end portion adapted for interlocking engagement is dovetail shape.

8. A tie as claimed in claim 6, wherein the end portion adapted for interlocking engagement is provided with projecting barbs or fins.

9. A tie as claimed in any of the preceeding claims wherein the central portion is arranged at an angle 450 to the longitudinal axis.

10. A tie as claimed in claim 2, wherein the maximum distance between the end walls of the central portion, as measured along the longitudinal axis of the element, determines the minimum distance between the two members in use of the tie.

11. A tie as claimed in any one of the preceding claims and made of plastics material.

12. A tie as claimed in any one of claims 1 to 10 and made of metal.

13. A tie, for securing a frame member to a wall member, comprising an elongate strip-like element whose end portions are adapted for securement to a respective one of the frame and wall members, and wherein the end portion for securement to the frame member is adapted for interlocking engagement therewith.

14. A tie as claimed in claim 13, wherein the end portion for securement to the frame member is dovetail shaped.

15. A tie as claim 13, wherein the end portion for securement to the frame member is provided with projecting barbs or fins.

1 6. A tie as claimed in any one of claims 13 to 15, wherein the end portion for securement to the wall member is provided with an aperture whereby to assist keying of the tie in mortar in use of the tie.

1 7. A tie as claimed in any one of claims 13 to 1 6 and made of a plastics material.

18. A tie as claimed in any one of claims 13 to 1 6 and made of metal.

19. A tie as claimed in any one of claims 13 to 18, wherein the tie end portions are arranged in a common plane and separate by a central portion which is tilted out of the common plane and extends at an angle to the longitudinal axis of the element.

20. A tie in combination with a frame member, which frame member is to be secured to a wall member by means of the tie in use of the combination, wherein the tie comprises an elongate strip-like element having one end adapted for interlocking engagement with a corresponding slot or aperture of the frame member, and wherein the other tie end is adapted to be secured in mortar of the wall member in use of the combination.

21. The combination as claimed in claim 20, wherein the one end of the tie and the slot are shaped such that the tie end may be inserted into and removed from the slot in one relative orientation thereof, whilst when the tie end is inserted into the slot and turned through 900 about the longitudinal axis of the tie the tie and frame are interlocked.

22. The combination as claimed in claim 21, wherein the one tie end and the slot are dovetail shaped.

23. The combination as claimed in claim 20, wherein the one tie end or the slot or aperture are provided with projecting barbs or fins.

24. The combination as claimed in any one of claims 20 to 23, wherein the tie ends are arranged in a common plane and separated by a central portion which is tilted out of the common plane about the longitudinal axis of the element and connected to the tie ends by end walls, which are subsequentlly perpendicular to the common plane and the longitudinal axis.

25. The combination as claimed in any one of claims 20 to 24, wherein the tie is made of a plastics material.

26. The combination as claimed in claim 24, wherein the central portion is tilted at an angle of 450.

27. A cavity wall tie substantially as herein described with reference to and as illustrated in Figs. 1 to 3, Fig. 6 or Fig. 7 of the accompanying drawings.

28. A frame tie substantially as herein described with reference to and as illustrated in Figs. 4 and 5 of the accompanying drawings.