GB2051920A

GB2051920A - Lintel With Arch Support

Info

Publication number: GB2051920A
Application number: GB8016562A
Authority: GB
Original assignee: DMS BUILDING COMPONENTS Ltd; PRESS BAT HOLDINGS Ltd
Current assignee: DMS BUILDING COMPONENTS Ltd; PRESS BAT HOLDINGS Ltd
Priority date: 1979-05-24
Filing date: 1980-05-20
Publication date: 1981-01-21
Also published as: GB2051920B

Abstract

A lintel assembly includes a combined arch support and damp- proof element (11) which rests on or is secured to a forwardly projecting horizontal plate (16) of lintel (10) which may have a box section body (12) of sheet metal. A lip (15) is provided on the lintel extending into the cavity but not bridging it. The damp-resisting portion (23) of the combined element (11) extends under the lip (15) to catch moisture which may be in the wall cavity and diverted towards the outer skin of masonry. The combined element is formed as a unitary structure, typically in glass fibre reinforced plastics. <IMAGE>

Description

SPECIFICATION Cavity Wail Arch Support This invention relates to an arch support for a building structure and to a method of using such an arch support to construct a masonry arch.

Arches have been a feature of building construction for many years. The construction of arches has in many cases involved extremely skilled design and building work, resulting in a pleasing aesthetic appearance.

Modern building techniques, particularly for house building and the like, have tended towards reducing building costs and building time. Skilled workmen have been growing fewer in number and expensive to employ.

Thus, in recent years the aesthetically pleasing arch has largely disappeared from moderately priced range house building in favour of squared openings.

Correctly constructed masonry arch is selfsupporting once it is complete. During construction, it needs to be supported from beneath, so that the masonry elements such as bricks or blocks may be laid and the joints mortared if required. The traditional method of making an arch involves the use of a temporary arch shaped former which is traditionally made of wood and which supports the masonry until the arch has been laid and the mortar joints (if any) are dried out. The formwork is then removed. If a door, window or the like is to be sited in such an archway, the portion between the door or window frame and the arch has been filled with a specially constructed timber member or alternatively the top of the window or door could be arch shaped to fit the space.Such methods clearly involve a great deal of skilled carpentry work, at least some of which must be performed on site, to ensure a good fit between the constituent parts.

The use of timber for such permanent arch fillers is unsatisfactory because timber tends to rot after a certain length of time.

Where the arch is to be formed in a cavity wall, the problems are even more acute in view of the fact that two leaves of masonry have to be supported and also in order to ensure that any dampness in the cavity is adequately dealt with. It would be necessary for example, in order to comply with the building regulations for an external wall to provide some form of damp proof tray within the cavity which would be capable of collecting any moisture in the cavity and diverting it outwardly towards the outer skin of masonry.

It has been proposed to support cavity walls by means of lintels of various types and it is an object of the present invention to provide a cavity wall lintel which enables a masonry arch to be constructed readily in the outer leaf of a cavity wall and incorporating integral damp resistant means.

According to the invention there is provided a lintel assembly for use in a cavity wall comprising, in combination, a lintal, and a combined arch-supporting and dampresisting element; the lintel being capable, in use, of spanning a gap in a cavity wall and being supprted by the masonry of the wall at opposed sides of the gap and comprising an inner-leafsupporting body and an outer-leaf-supporting plate or part projecting forwardly and generally horizontally from a lower portion of the body so as to span the cavity of the cavity wall, the body including a forward lip extending longitudinally of the body at a position above the flange, towards or into, but not bridging, the cavity and projecting generally downwardly;; the combined arch-supporting and dampresisting element being formed as an elongate unitary structure in a rigid material and comprising a forward portion positioned at least approximately within the outer leaf of the wall in use and including an arch-supporting portion disposed centrally of the length of said element and having a segmental front face and an arcuate upper surface which is generally horizontal in any plane perpendicular to the length of said element and which is approximately equal in length to the gap to be bridged, and a damp-resisting portion disposed rearwardly of, and extending upwardly from the forward portion of the element-so as to span the cavity in use, and projecting under the forward lip of the lintel body so as to receive any moisture draining therefrom and divert it forwardly towards the outer leaf of the cavity wall.

The expressions "forwardly", "upwardly" and the like are intended to refer to the normal positioning of the lintel assembly in use in a cavity wall having an inner and an outer saf of masonry.

The body of the lintel may comprise a hollow box section of sheet metal, which may include a plurality of internal stiffeners or may comprise a concrete lintel or a rigid steel section.

End flanges may extend from each end of the arch-supporting portion of said element to overlie closely the outer-leaf-supporting plate or part of the lintel, the end flanges being integrally formed with the arch-supporting and damp-resisting portions.

Preferably, the combined arch-supporting and damp-resisting element is formed as a one-piece moulding in a synthetic plastics material. For example, the element may be formed of glass fibre reinforced polyester or polyurethane.

The invention will now be described in more detail by way of example only with reference to the accompanying drawings in which: Figure 1 is a front perspective view of a lintel assembly embodying the invention; Figure 2 is a perspective view from the front and one side of the same lintel assembly; Figure 3 is a side perspective view of the same lintel assembly.

Referring firstly to Figure 3 of the drawings, a lintel assembly comprises a lintel generally indicated at 10 and a combined damp-resisting and arch-supporting element generally indicated at 11 and hereinafter referred to as a "combined element".

The lintel is made of sheet metal and includes a box section body 12 having internal stiffeners 13 at spaced positions along its length. The top of the box section body is formed by a corrugated top plate 14 which has, at its forward edge, a forwardly and downwardly projecting lip 1 5 extending into, but not across, the cavity in use.

The top plate 14 and the other members of the box section body are formed as cold rolled sections in light weight steel sheet and may be treated with any suitable rust resistant material, For example, pre-galvanised sheet may be used.

The box section body 12 provides a support for an inner leaf of brickwork or other masonry of a cavity wall.

The outer leaf of the cavity wall is supported by a plate or part 1 6 which projects forwardly and generally horizontally from a lower portion of the body 12. The expressions "upper", "lower" and the like are used in relation to the lintel in its condition of use in a cavity wall.

The lip 15 need not be provided on the top plate 14 but must be spaced above the plate or part 16.

The lintel 10 is intended to span a gap in a cavity wall (not shown) the end portions of the lintels resting on the masonry below the lintel at each side of the gap. Suitable plaster key or similar covering arrangements are provided on the lintel in accordance with the use for which is it intended.

The lintel assembly also comprises a combined element 11 which is made, in a preferred embodiment, as a one-piece moulding in a synthetic plastics material. Typical plastics which may be used are glass fibre reinforced polyester or polyurethane. The combined element is required to have a sufficient rigidity to support a number of masonry elements such as bricks or blocks during the assembly of an arch. However, once the arch has been constructed and, if mortar joints are used, these have been allowed to set, the arch becomes self-supporting and hence the load bearing requirements of the combined element are limited. The expression "rigid" as used in connection with the material of which it is made are to be interpreted accordingly.

The combined element includes an archsupporting portion 1 7 which is disposed centrally of the length of the element as seen in Figure 1.

The arch-supporting portion 1 7 includes a front face 18 which is at least approximately in the shape of a segment of a circle. It also includes an arcuate upper surface 1 9 which is approximately horizontal at each increment of its length taken in planes perpendicular to the length of the element.

Thus, the arcuate surface 1 9 presents, at each point along its length. a generally horizontal surface on which the bricks or other masonry elements can be laid to form an arch.

As can be seen in Figure 3 of the drawings in particular, the arcuate upper surface 1 9 is provided with an indentation 20 running along its length which is used partly to add rigidity to the arch and partly as a key for mortar used in assembling the arch.

At each end of the arch-supporting portion 1 7, end flanges 21 extend along in a generally horizontal plane, closely overlying the plate or part 16 of the lintel. The end flanges 21 may be provided with ribs 22 or the like as a mortar key, to rigidify the flanges and to deflect moisture outwardly.

The combined element also includes a dampresisting portion 23 which is in the form of a flat plate extending integrally from the rearward edge of the arcuate upper surface 1 9 and the end flanges 21 and extending upwardly and rearwardly across the cavity of the wall in use.

The damp-resisting portion 23 projects under the lip 1 5 of the lintel top plate 14. It may be located against movement by the lip or may be loose as shown. However, it is a requirement that the lip should overlie the damp-resisting portion at least at its upper edge so that any moisture which may gather within the cavity towards the inner leaf of the cavity wall will drip from the lip 15 onto the inclined damp-resisting portion and will be diverted forwardly across the cavity towardsthe outer leaf of masonry.

At the extreme forward edge of the combined element 11, a drip lip 24 is provided which extends outwardly beyond the forward end 25 of the plate or part 16.

In use, the upright segmental front face 1 8 of the combined element 11 shows at the forward face of the masonry and will be set back about one or two centimetres from the front face of the masonry. Any water running down the wall on the outer face may fall onto the outer facejof the archsupporting portion and thence onto the drip lip 24, which prevents it from seeping rearwardly into the masonry.

Although it is preferred that the combined element should be secured to the lintel, for example by clips attaching the end flanges 21 to the plate or part 16, it may be formed as a separate element to be assembled with a generally conventional lintel on site. In this case, the lintel need not include a box section body but could have, for example, a concrete body or a heavy rolled metal section, provided that it included a forward lip extending longitudinally of an upper portion of the body so that the combined element can be inserted under the lip.

In use, an arch is formed by laying bricks or other masonry elements, together with mortar if required, on the arcuate upper surface 1 9 of the combined element, the front face 1 8 being somewhat inset into the masonry and the drip lip 24 receives moisture from the lower edge of the masonry above the gap.

Once the arch has been formed and is selfsupporting (that is any mortar used has set) subsequent courses of brickwork can be built up to form the outer leaf of the wall above the arch and of course the construction of the inner leaf of masonry will have been uninterrupted by the construction of the arch and will have continued on the lintel body 12.

The lip 1 5 of the top plate of the lintel will lead any moisture onto the inclined damp-resisting portion of the combined element and will lead it forwardly to the front of the cavity, as required by good building practice.

Since the combined element is made of synthetic plastics material, it is impervious to water and does not rot over a period of use. It is also unlikely to shrink or warp, which would be likely to happen to a timber arch filler.

It is also possible to produce various colours or decorative patterns to be visible in the flat arch, on the front face of the combined element.

Claims

1. A lintel assembly for use in a cavity wall comprising, in combination, a lintel, and a combined arch supporting and damp resisting element the lintel being capable, in use, of spanning a gap in a cavity wall and being supported by the masonry of the wall at opposed sides of the gap and comprising an inner-leafsupporting body and an outer-ieaf-supporting plate or part projecting forwardly and generally horizontally from a lower portion of the body so as to span the cavity of the cavity wall, the body including a forward lip extending longitudinally of the body at a position above the flange, towards or into, but not bridging, the cavity and projecting generally downwardly;; the combined arch-supporting and dampresisting element being formed as an elongate unitary structure in a rigid material and comprising a forward portion positioned at least approximately within the outer leaf of the wall in use and including an arch-supporting portion disposed centrally of the length of said element and having a segmental front face and an arcuate upper surface which is generally horizontal in any plane perpendicular to the length of said element and which is approximately equal in length to the gap to be bridged, and a damp-resisting portion disposed rearwardly of and extending upwardly from the forward portion of the element so as to span the cavity in use, and projecting under the forward lip of the lintel body so as to receive any moisture draining therefrom and diverted forwardly towards the outer leaf of the cavity wall.

2. A linter assembly according to claim 1 wherein the body of the lintel comprises a hollow box section of sheet metal.

3. A lintel assembly according to claim 2 wherein the box section has a plurality of internal stiffeners.

4. A lintel assembly according to claim 1 wherein the body of the lintel is of concrete.

5. A lintel assembly according to claim 1 wherein the body of the lintel comprises a rigid steel section.

6. A lintel assembly according to any preceding claim wherein end flanges extend from each end of the arch-supporting portion of said element to overlie closely the outer-leaf-supporting plate or part of the lintel, the end flanges being integrally formed with the arch-supporting and dampresisting portions.

7. A lintel assembly according to any preceding claim wherein the combined arch-supporting and damp-resisting element is formed as a one piece moulding in a synthetic plastics material.

8. A lintel assembly according to claim 7 wherein the plastics material is glass fibre reinforced polyester.

9. A lintel assembly according to claim 7 wherein the plastics material is glass fibre reinforced polyurethane.

10. A lintel assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.