GB2286209A - Wall and method of constructing the same - Google Patents

Abstract

A method of constructing a wall of a building comprising the steps of providing one or more conduits (26) in the space to be occupied by the wall, disposing respective first and second shuttering means (18, 20) in face-to-face relationship with said one or more conduits disposed therebetween, securing said first and second shuttering means with respect to each other, and at least partially filling the space defined between said first and second shuttering means with a flowable concrete mixture so that said mixture surrounds said one or more conduits and sets to form the said wall. <IMAGE>

Description

WALL AND METHOD OF CONSTRUCTING THE SAME The present invention relates to a wall and to a method of constructing a wall and is therefore of particular relevance to the construction industry and to buildings in general.

In the past houses and other buildings have typically been constructed with an outer brick skin which is spaced from an inner skin of light weight breeze block by a small air gap.

Plaster is then applied to the inner surface of the breeze block skin to provide a smooth and uniform surface for the owner or resident to decorate according to their own taste.

One of the problems with such a construction however, is that the means for delivering the various services expected of a modern building such as, electricity, water, heat, communications and waste disposal, all have to be routed at the very beginning of the construction process. Once the building has been completed the task of re-routing one or more of the services is not only expensive but also results in the building being festooned with service pipes either on the inside or the outside. Such an array of service pipes is generally not regarded as being pleasing to the eye and may even affect the value of the property.

One way of overcoming this problem would be to make use of the openings provided in each of the breeze blocks of the inner skin. These openings, which are normally in alignment with each other once the inner skin has been constructed, can be thought of as defining a service duct of sufficient size to accommodate most, if not all, of the means needed to deliver the various services. The problem is however, that such a use of the openings would not meet existing building regulations unless the duct defined by the openings is first lined with a conduit which itself meets those regulations.Since it would not be possible to feed such a conduit through the aligned openings once the inner skin has been constructed, such a scheme would necessitate the construction of the inner skin in such a way as to involve the sliding of successive breeze blocks over a previously erected, generally vertically extending conduit. This is clearly not a commercial proposition.

The reason why existing building regulations insist upon the openings of the breeze block being lined with a separate conduit if used in the manner proposed is because as the blocks become ever lighter and more thermally efficient as block making technology advances, the blocks themselves become weaker and weaker. If, say, a water main was routed through a series of unlined openings within the breeze block skin and that water main subsequently burst, the breeze block skin would collapse causing untold damage to the building and to its inhabitants and contents. Faced with this regime the manufactures of breeze blocks tend to fill the openings of each block with a foam plastic to help improve their strength and increase their thermal efficiency and inertia. Of course, once the openings have been filled in this way they can no longer be used for routing building services.

The present invention is directed to a wall and a method of constructing a wall which, at least in part, addresses some of the problems of the prior art.

According to a first aspect of the present invention there is provided a method of constructing a wall of a building comprising the steps of providing one or more conduits in the space to be occupied by the wall, disposing respective first and second shuttering means in face to face relationship with said one or more conduits disposed therebetween, securing said first and second shuttering means with respect to each other, and at least partially filling the space defined between said first and second shuttering means with a flowable concrete mixture so that said mixtures surrounds said one or more conduits and sets to form the said wall.

Advantageously, the method may comprise the additional step of securing said one or more conduits with respect to one or both of said first and second shuttering means.

Advantageously, a supporting member may be disposed between said first and second shuttering means to which said one or more conduits are secured. Preferably the supporting member may comprise a mesh.

Advantageously, the method may comprise the additional step of providing one or more reinforcing members in the space defined between said first and second shuttering means.

Advantageously, said one or more conduits may be provided with an external rib or projection to facilitate the binding of the one or more conduits with the concrete mixture.

Advantageously, said one or more conduits may be formed of steel.

Advantageously, the method may comprise the additional step of removing one or both said first and second shuttering means once the flowable concrete mixture has set.

Alternatively, one or both of said first and second shuttering means may be of the "vanishing" type and may display waterproof and/or damp-proof properties. Preferably, one or both of said first and second shuttering means may be provided on a surface facing said one or more conduits with a layer which displays the waterproof and/or damp-proof properties.

Preferably one or both of said first and second shuttering means may comprise a thermally insulating material.

Advantageously, the method may comprise the additional step of providing secondary skin spaced from said first and second shuttering means in such a way as to define an air gap therebetween. Preferably the secondary skin may be secured to one or both of said first and second shuttering means.

Advantageously, the method may comprise the additional step of applying a layer of plaster on a surface of the shuttering means spaced furthest from the secondary skin.

Advantageously, the concrete mixture may be caused to set in such a way that access may be gained to at least one end of said one or more conduits in one of a crawl space at or below ground level, in a roof space or at an aperture in the wall such as a door, window or arch.

Advantageously, the method may comprise the additional step of providing a further conduit that extends within the space to be occupied by the wall transversely of said one or more conduits and which communicates with each of the one or more conduits in turn.

Advantageously, said one or more conduits may be provided with a T-Section which extends from the conduit to substantially flush with a surface of one of said first or second shuttering means remote from the space to be at least partially filled by the flowable concrete mixture. Preferably the T-section may be adapted to be concealed behind a skirting board, picture rail or some other suitable decorative feature.

According to a second aspect of the present invention, there is provided a wall constructed in accordance with any of the aforementioned methods.

According to a third aspect of the present invention, there is provided a method of constructing a building, the method including the step of constructing a wall in accordance with any of the aforementioned methods.

According to a fourth aspect of the present invention, there is provided a building constructed in accordance with any of the aforementioned methods.

A number of embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a schematic view of a horizontal cross-section taken through a generally vertically extending wall; Figure 2 is a schematic view of a vertical cross-section taken through a generally vertically extending wall; Figure 3 is a schematic view of a horizontal cross-section taken through a basement section of the wall of Figures 1 and 2; Figure 4 is a schematic view of a vertical cross-section of the wall of Figures 1 to 3 showing the lower part of a window; and Figure 5 is a schematic view of a vertical cross-section of the wall of Figures 1 to 4 and showing the upper portion of a window.

Referring to Figure 1 there is shown a horizontal cross section through a generally vertically extending wall 10. As is conventional, the wall 10 is comprised of an outer skin 12 which is spaced from an inner skin 14 by an air gap 16. The outer skin 12 may be of any desired facing material such as stone, brick or concrete.

The inner skin 14 is itself comprised of an inner shuttering 18 and an outer shuttering 20 both of which occupy generally parallel planes and are separated by a layer of concrete 22. The inner shuttering 18 and outer shuttering 20 are secured with respect to each other by means of one or more cross-ties 24 which may be of any known design such as those used in cavity wall construction. As shown in Figure 1, the outer skin 12 may be secured with respect to the inner skin 14 by means of an extension of the same cross-ties 24.

Within the concrete layer there are disposed a plurality of generally vertically extending conduits 26 which are uniformally spaced apart and which are substantially equidistant from the inner shuttering 18 and the outer shuttering 20. A reinforcing mesh 28 extends through the concrete layer 22 in a plane generally parallel to both the inner shuttering 18 and the outer shutting 20 and is provided with means 30 for attachment to each of the conduits 26. At regular intervals along the wall 10, a conduit 26 is omitted and its place taken by a reinforcing pillar 32. To complete the wall 10, the inner surface of the inner shuttering 18 is provided with a coating of plaster 34.

In order to construct a wall 10 of the type illustrated in Figure 1 it is first necessary to erect the reinforcing mesh 28 in the space to be occupied by the concrete layer 22. The various conduits 26 and reinforcing pillars 32 are then secured to the mesh 28 by virtue of the attachment means 30 before then being surrounded on opposite sides by the inner shuttering 18 and the outer shuttering 20. The two shutterings 18 and 20 are secured with respect to each other by means of one or more cross-ties 24 and once secured a flowable concrete mixture is pumped into the space defined between the shutterings to surround and encase all three of the conduits 26, the reinforcing mesh 28 and the reinforcing pillars 32.Finally, the outer skin 12 is constructed a small distance from the outer shuttering 20 so as to leave an air gap 16 and the outer skin attached to the inner skin 14 by means of the end tails of the cross-ties 24.

Clearly, the reinforcing mesh 28 serves the two fold purpose of both retaining the conduits 26 and the reinforcing pillars 32 in mutual alignment while at the same time serving as a tie between successive casts of the flowable concrete mixture. Nevertheless, it will be apparent to those skilled in the art that a wall may be constructed in accordance with the present invention without using any additional member to support either the conduits 26 or reinforcing pillars 32, particularly where the wall is of limited dimensions.

Likewise, it will be apparent that the reinforcing mesh 28 may be replaced by two or more verically spaced strands of wire which extend between the conduits 26 and reinforcing pillars 32 in a direction generally parallel to both the inner shuttering 18 and the outer shuttering 20. Having said that, the use of a steel mesh having a mesh size of 200mm x 200mm and a wire gauge of 7mm has been found to be particularly advantageous.

The conduits 26 are preferably of galvanised mild or stainless steel as this enables the conduits to both meet existing fire regulations and contribute massively towards the flexural strength of the resulting wall 10. Conduits 26 formed of other materials such as plastics may also be used where the building regulations, and particularly the fire regulations, permit.

In a preferred embodiment, the conduits 26 are formed of spirally wound galvanised mild steel and have a diameter of approximately 125mm. Conduits of this type have at least three advantages. Firstly, they are relatively inexpensive and so enable a wall 10 to be constructed in which the conduits are spaced five to the meter. This density of conduits 26 not only provides a plurality of paths by which the services to the building may be routed but also provides a large number of subsidiary air gaps within the inner skin 14 which has the affect of increasing the thermal efficiency of the wall as a whole. Furthermore, the presence of a large number of conduits 26 also means that less concrete is needed to form the concrete layer 22. In fact the amount of concrete required approximates to that necessary to form the breeze blocks of the prior art.

A second advantage of steel conduits is that when they are used in conjunction with a steel reinforcing mesh 28 as is currently preferred, the various attachments means 30 may simply comprise one or more welding joints.

A third, and perhaps less obvious advantage of using spirally wound steel conduits, is that the spiral rib which necessarily extends along the outer surface of the conduits enable the conduits to bind more readily with the concrete mixture when this is pumped between the two shutterings 18 and 20 thereby providing a stressed skin that greatly increases the flexural strength of the wall.

Galvanised mild steel conduits of the aforementioned type are sold in the United Kingdom by J.P.C. Pressplan Limited of Springmill Street, Bradford, BD5 7DU.

In order to provide the inner skin 14 with enhanced structure and load bearing properties, the reinforcing pillars 32 are preferably spaced at appropriate intervals, intersections or changes of direction, typically at no more then two meter intervals. These pillars are preferably also made of steel and have a hollow square cross section in which each side has a dimension of approximately 120mm and a thickness of 5.3mm. Having said that, it will be apparent to those skilled in the art that a wall may be constructed in accordance with the present invention without incorporating any such reinforcing member or members where the dimensions of the wall and the loads it has to bear so permit.

The inner and outer shutterings 18 and 20 serve a number of different purposes. One such purpose is clearly to provide a surface against which the flowable concrete mixture may be cast. In this regard one or both of the shutterings 18 and 20 may be of the "vanishing" type and so be incorporated into the final wall 10. Alternatively, one or both of the shutterings 18 and 20 may be of the "non-vanishing" type thereby necessitating its removal from the inner skin 14 once the concrete layer 22 has been allowed to set. In either case, in order to enable the concrete mixture to be successfully cast against it, each of the shutterings 18 and 20 preferably display waterproof and damp-proof properties at least on that surface facing the conduits 26. These waterproof and damp-proof properties however, may come about either as a result of the inherent nature of the shuttering used or as a result of the presence of a waterproof and damp-proof layer applied to the surface of an otherwise non-waterproof and non-damp-proof shuttering material.

The preferred nature of the two shutterings 18 and 20 to display waterproof and damp-proof properties on at least that surface which faces the conduits 26 leads directly to one advantage of employing shuttering of the "vanishing" type since by doing so the wall 10 is automatically provided with at least two damp course layers.

In one preferred embodiment the outer shuttering 20 is indeed of the "vanishing" type. Under such circumstances, as well as displaying waterproof and damp-proof properties, the outer shuttering 20 is preferably formed of a thermally insulating material. One such material is sold by Pittsburgh Corning Corporation under the trade mark FOAMGLAS. FOAMGLAS is a cellular glass insulation material and as well as being both waterproof and damp-proof also displays a high thermal efficiency. In addition, FOAMGLAS displays the additional advantages of having a high compressive strength, being dimensionally stable, being non-combustible and resistant to rodents and other vermin.

If the outer shuttering 20 displays the necessary thermal efficiency then the inner shuttering 18 can simply comprise conventional plaster board with a waterproof and damp-proof backing layer on the surface which is to face the conduits 26.

In this way the surface of the inner shuttering 18 which is remote from the concrete layer 22 may provide a suitable surface for the application of the plaster coating 34.

The inner and outer shutterings 18 and 20 are secured with respect to each other by means of cross-ties 24 to prevent the shutterings from bursting or moving apart as the concrete mixture is pumped between the two. The cross-ties 24 may be of any convenient type and in the example shown, comprise lengths of twelve gauge stainless steel wire which are fed through small openings in both the inner and outer shutterings 18 and 20 and secured by sprung fix plates. If so desired, the cross-ties 24 may be secured to the reinforcing mesh 28 by means of one or more spot welds or some other suitable attachments means.

Assuming that the outer shuttering 20 is separated from the outer skin 12 by an 87.5mm air gap and that the outer skin 12 is 102.5 mm thick, then the wall 10 illustrated in Figure 1 will have an overall thickness of 540mm. Such a wall more then meets the building regulations for strength and thermal efficiency. Furthermore, because the conduits 26 are encased in the concrete layer 22, the conduits satisfy all the necessary fire regulations. Other advantages of the wall as herein described stem from the fact that the main bulk of the construction material is within the thermal barrier defined by, on the one hand, the air gap 16 and the thermally insulating outer shuttering 20, on the other hand by the inner shuttering 18. As a result the wall 10 exhibits a significant thermal inertia.

Another advantage of the wall 10 is its low cost of construction which comes about as a result of the fact that pumped full weight concrete delivered to the site by truck is actually cheaper on an occupied volume basis than conventionally strengthened breeze blocks.

Of course, one of the main advantages of the method of construction herein described is that as a result of the large number of conduits 26, a choosen service may be delivered to almost any point on any wall within the building without requiring any subsequent structural alterations.

Access to the conduits 26 may be achieved in a variety of ways. For example, in one currently preferred embodiment access is obtained from behind the skirting board. In this way should it be desired to re-route any service once the building has been constructed all that would be necessary in the worst case is for a section of the skirting board to be replaced.

An example of this arrangement is shown in Figure 2, where it can be seen that each of the conduits 26 is provided with a blind T-section 36 which extends from the conduit to be flush with the plaster coating 34 on the internal surface of the inner shuttering 18. The blind T-section 36 is normally hidden from view by the skirting board 38 but if necessary the skirting board 38 can be removed and the blind T-section opened in order to gain access to the conduits 26.

In another arrangement, which is also illustrated in Figure 2, access to the conduit 26 is again achieved by means of a blind T-section 36 which, as before, extends from the conduit to flush with the plaster coating 34 on the inner surface of the inner shuttering 18. On this occasion however, the blind T-section 36 is obsecured from normal view by means of a picture rail 40 or some other suitable decorative feature.

In yet another arrangement, a ring duct may be provided which extends generally transversely of the conduits 26 in order to communicate with each of them in turn. Such a ring duct may be provided at the height of one or both of the skirting board 38 and picture rail 40 and so allow easy access to any one of the conduits 26 and the re-rooting of a service from one conduit to another. Thus, for example, in a building housing both electrical equipment and air conditioning apparatus, a ring duct provided behind a skirting board may serve the dual purpose of facilitating the routing of electrical cables while also acting as an air plenum chamber for diffusion into the room while a ring duct at the height of a picture rail or some other decorative feature may serve as an exhaust plenum.

In yet another arrangement, access to the conduits 26 may be attained from a crawl space below the ground floor level or from a basement if such is provided. A typical basement arrangement is shown in Figure 3 to comprise a modified concrete layer 42 which is cast against a specially shaped inner shuttering 44 so as to allow free and unimpeded access to at least a portion of each of the conduits 26. Within these portions the material of which the conduits are formed is partially cut away so as to allow the introduction to the conduits of the various means for delivering the required services.

In yet another arrangement, access to the conduit 26 may be gained from within the roof space. An example of one such arrangement is illustrated in Figure 2 in which each of the conduits 26 is shown to be closed at its upper end by means of a hinged cap 46. By removing one or more tiles 48 from the roof 50 and then pivoting the cap 46 about its hinged connection to the conduit 26 it is possible to either introduce or extract from the conduits any one of the various means required to deliver the necessary services. In this way, for example, a communications cable or water supply may be fed from one conduit 26 to another spaced some distance from it.

In yet another arrangement, where the building is provided with one or more windows 52, access to the conduit 26 may be gained by temporarily removing one or more of the window ledges 54. An example of one such arrangement is illustrated in Figure 4, where the conduit 26 is again shown to be closed at its upper end by means of a cap 46.

Where there are windows 52, access may also be gained to the conduits 26 by temporarily removing a fascia panel 56 provided above the window and which extends from the window to the inner shuttering 18. An example of one such arrangement is illustrated in Figure 5, where again the conduit 26 is shown to be closed, albeit at its lower end, by a cap 46.

By virtue of the plurality of conduits 26 and the many ways in which access may be gained to them, it will be apparent to those skilled in the art that in addition to the other advantages previously mentioned, the method of construction herein described enables the entire provision of services to be removed from the critical path involved in the erection of a modern building. This in itself will reduce building time and represent a significant saving in costs.

Claims (25)

1. A method of constructing a wall of a building comprising the steps of providing one or more conduits in the space to be occupied by the wall, disposing respective first and second shuttering means in face-to-face relationship with said one or more conduits disposed therebetween, securing said first and second shuttering means with respect to each other, and at least partially filling the space defined between said first and second shuttering means with a flowable concrete mixture so that said mixture surrounds said one or more conduits and sets to form the said wall.

2. A method in accordance with Claim 1 and comprising the additional step of securing said one more more conduits with respect to one or both of said first and second shuttering means.

3. A method in accordance with Claim 1 or Claim 2, wherein a supporting member is disposed between said first and second shuttering means to which said one or more conduits are secured.

4. A method in accordance with Claim 3, wherein said supporting member comprises a mesh.

5. A method in accordance with any preceding claim and comprising the additional step of providing one or more reinforcing members in the space defined between said first and second shuttering means.

6. A method in accordance with any preceding claim, wherein said one or more conduits are provided with an external rib or projection to facilitate the binding of said one or more conduits with said concrete mixture.

7. A method in accordance with any preceding claim, wherein said one or more conduits are formed of steel.

8. A method in accordance with any preceding claim and comprising the additional step of removing one or both of said first and second shuttering means once the flowable concrete mixture has set.

9. A method in accordance with any of claims 1 to 7, wherein one or both of said first and second shuttering means is of the "vanishing" type and displays waterproof and/or damp-proof properties.

10. A method in accordance with claim 9, wherein one or both of said first and second shuttering means is provided on a surface facing said one or more conduits with a layer which displays said waterproof and/or damp-proof properties.

11. A method in accordance with claim 9 or claim 10, wherein one or both of said first and second shuttering means comprises a thermally insulating material.

12. A method in accordance with any preceding claim and comprising the additional step of providing a secondary skin spaced from said first and second shuttering means in such a way as to define an air gap therebetween.

13. A method in accordance with claim 12, wherein said secondary skin is secured to one or both of said first and second shuttering means.

14. A method in accordance with claim 12 or claim 13 and comprising the additional step of applying a layer of plaster on a surface of the shuttering means spaced furthest from said secondary skin.

15. A method in accordance with any preceding claim, wherein said concrete mixture is caused to set in such a way that access may be gained to at least one end of said one or more conduits in one of a crawl space at or below ground level, in a roof space or at an aperture in said wall such as a door, window or arch.

16. A method in accordance with any preceding claim and comprising the additional step of providing a further conduit that extends within the space to be occupied by the wall transversely of said one or more conduits and which communicates with each of said one or more conduits in turn.

17. A method in accordance with any preceding claim, wherein said one or more conduits are provided with a T-section which extends from the conduit to substantially flush with a surface of said first or second shuttering means remote from the space to be at least partially filled by said flowable concrete mixture.

18. A method in accordance with claim 17, wherein said T section is adapted to be concealed behind a skirting board, a picture rail or some other suitable decorative feature.

19 A method of constructing a wall substantially as herein described with reference to the accompanying drawings.

20. A wall constructed in accordance with the method of any of claims 1 to 19.

21. A wall substantially as herein described with reference to the accompanying drawings.

22. A method of constructing a building, said method including the step of constructing a wall in accordance with the method of any of claims 1 to 19.

23. A method of constructing a building substantially as herein described with reference to the accompanying drawings.

24. A building constructed in accordance with the method of claim 22 or claim 23.

25. A building substantially as herein described with reference to the accompanying drawings.