Improvements in or relating to building components

The present invention relates to components used in the construction industry and in particular, though not exclusively, to an acoustic and vibration isolator for use at wall and floor junctions in masonry and blockwork structures involving houses and apartments.

Sound and vibration transmission from typical living activities within apartments or houses travels directly through separating floors between apartments and also directly through separating walls between apartments or houses. Another important path or mechanism for sound transmission is via the lateral or flanking structures such as other floor and wall elements present in the building (e.g. external wall). Thus even if the primary separating or dividing wall or floor between apartments is a very significant structure providing good isolation and or mass the performance of the separating wall or floor will be entirely limited and restricted in its potential performance by the structural junctions with other building elements (e.g. other walls). These other structures will also transmit sound and vibration and thus be a limiting factor in the overall wall or floor performance.

Considering blockwork apartments as an example. A masonry wall leaf of blocks is built to the required storey height. A precast concrete slab or concrete floor element is laid upon the wall head to form a wall-floor junction. Mortar or dry infill is located between the wall head and the slab. The wall leaf is then continued above the slab to form the wall of an upper storey. Mortar is applied between the slab and the first block of the upper structure also. An illustration of this arrangement is shown in Figure 1.

Such a construction has a number of disadvantages. There are multiple transmission paths for sound (airborne and impact sound). The path

marked A is well understood and insulation is generally located under the floor boards to combat this. However, flanking transmission, by the path marked B, is the controlling factor and limits the sound and vibration performance between the floors.

The slab may have a camber in its form or the wall head may be uneven. Consequently gaps can exist between the wall head and the slab. Such gaps lead to air leakage and reduce the energy performance of the building envelope. In masonry or blockwork walls with mortar type bedding it is common practice to use a mortar type or equivalent type wet or dry based infill to this junction and gap. As a result this is often not done correctly as the infill material extrudes, or is pushed through or falls out the other side of the junction and gap. As such the gap is not properly filled and sealed and there is still air leakage and heat loss at this junction. Consequently, the energy efficiency of the building envelope is not maximised.

A yet further disadvantage of this construction is that it is common for mortar or infill material to extrude, or be pushed or fall down the other sides of the junction. This can:

- collect on wall ties which are present in cavity walls (which can adversely increase sound transmission across walls leafs) which would require to be cleaned and or removed,

- fall down to the base of the cavity wall and collect and form an acoustic bridge between wall leafs which would be detrimental for the wall's sound insulation for cavity walls and requires to be cleaned and or removed.

- fall onto the face of the wall, particularly for single leaf walls, and reduce the visual appearance of the wall and require cleaning and removal.

It is an object of the present invention to provide an acoustic isolator for use at junctions in building construction which obviates or mitigates at least one of the disadvantages of the prior art.

It is a further object of the present invention to provide a method of constructing a joint in a building which provides enhanced acoustic performance over prior art methods.

According to a first aspect of the present invention there is provided an acoustic isolator for use at junctions of structural elements in construction, the isolator comprising a first planar member and a second planar member, the members being arranged substantially perpendicular to each other, the first planar member being adapted to lie within a joint between the structural elements and the second member being adapted to rest against a side of at least one structural element when the first member is located thereupon, and wherein at least one of the members is formed from a damping material.

By lying within a joint which may be a mortar joint the isolator does not raise the overall building height or wall thickness and thus can be incorporated into a building without the need to adjust the dimensional drawings.

Within this description an isolator is a decoupler, with an acoustic isolator decoupling the noise and vibration transmission through the isolator. Additionally, a damping material is a material with improved damping characteristics e.g. lower sound and vibration transmission, relative to typical structural building materials such as blocks, bricks, timber and mortar.

A mortar joint is typically 10mm thick. Preferably the first member has a thickness less than 10mm. More preferably the first member has a thickness in the range 2 to 5 mm. Advantageously the second member is the same thickness to the first.

Preferably the second member is a downstand from the first member. A downstand assists in locating the isolator on a wall head by locating against the side of the wall head. In this way the first and second members meet along an edge which is arranged on the edge of the wall head. Thus the isolator may be more stable and be able to grip the wall head and avoid slipping off. Where the joint is a mortar joint, the downstand may provide a retaining function to contain the mortar within the joint when mortar is located under the isolator.

The isolator may further include attachment means for attaching the isolator to a structural element. The attachment means may be grippers on a surface thereof or be an adhesive or other bonding treatment applied to the isolator, if required.

Preferably the first member has a width similar to a width of a wall head. A wall head is considered to be a single wall leaf or multiple wall leafs having a cavity therebetween. By making the width approximately equal to the width of a wall head, the isolator may be considered as a cap fitting over the wall head and edged by the second member.

The isolator may include a third planar member. The third planar member may lie perpendicular to the first member opposite to the second member.

The third planar member may provide a second downstand. Such an embodiment provides a cap over the structural element. The cap may grip the structural element to prevent relative movement thereof. Advantageously the isolator forms a wall head cap.

Alternatively the third member may provide an upstand. Such an embodiment provides a lip which reduces the potential for mortar or joint infill material to spill into wall cavities. Where a dry joint is used the upstand may assist in locating the second structural element of the joint.

In a further embodiment the third planar member has a first portion arranged as an upstand and a second portion arranged as a downstand. Such an arrangement provides a cap to grip the element while also providing a lip to reduce mortar extrusion. In an embodiment the upstand and downstand may be formed separately with there being an overlap between. The overlap may be sealed with an acoustic sealant.

The third member may be formed of the same material as the first and second members.

Alternatively the second and/or third members may be composed of a non acoustic-vibration function material.

The members may be formed as overlapping members or they may be integral to provide a single piece isolator.

Preferably the damping material exhibits very high acoustic damping. Preferably the damping material is a high energy absorber. Preferably the damping material is foldable having no or little material memory. In this way the isolator can be shaped on site.

Preferably the damping material is a bitumen based flexible material. More preferably the material is a bitumist aluminium structure.

Preferably at least the first member comprises a surface formed to reduce it's contact area with a neighbouring component. In this way, the sound and vibration transmission is reduced.

Preferably at least the first member is a layered structure. More preferably at least one member is formed from a compressible material.

According to a second aspect of the present invention there is provided a method of constructing a joint in a building comprising the steps:

(a) constructing a first structure; (b) arranging an isolator according to the first aspect along at least a portion of a mating edge of the first structure; and (c) bringing a mating edge of a second structure to the mating edge of the first structure with the isolator therebetween.

In this way the isolator not only provides an acoustic impedance at the joint, but also reduces air leakage and heat loss.

The first structure may be a wall leaf which is built to the height for a next structural level e.g. a slab or floor bearing wherein a slab bearing is a structure forming a floor or a roof. In this embodiment the second structure is a slab forming a floor or roof on the wall head.

Alternatively the first and second structures may be wall leafs.

Preferably the method includes the step of arranging the isolator along the entire mating edge of the first structure. The isolator may be in overlapping parts or may be a continuous strip.

The method may include the step of levelling the mating edge of the first structure prior to bringing in the second structure.

Optionally, the method may include the step of forming a dry or wet joint between the mating surfaces.

The method may include the step of pushing mortar or infill against an upstand of the isolator.

Embodiments of the invention will now be described, by way of example only, and with reference to the following drawings, in which:-

Figure 1 is a schematic illustration of a section through a wall-floor joint in a blockwork building according to the prior art;

Figures 2(a) and 2(b) are section and plan views respectively of an isolator according to an embodiment of the present invention;

Figures 2(c) and 2(d) are section and plan views respectively of an isolator according to a second embodiment of the present invention;

Figures 2(e) and 2(f) are section and plan views respectively of an isolator according to a third embodiment of the present invention;

Figure 3 is a schematic illustration of a section through a wall-floor joint incorporating the isolator of Figures 2(a) and (b);

Figure 4 is a schematic illustration of a section through a wall-wall joint incorporating the isolator of Figures 2(a) and (b) over two wall leafs; and

Figure 5 is a schematic illustration of a section through a wall-floor joint incorporating the isolator of Figures 2(a) and (b) over two wall leafs;

Reference is initially made to Figures 2(a) and 2(b) of the drawings which illustrates an acoustic isolator, generally indicated by reference numeral 10, according to an embodiment of the present invention. Isolator 10 comprises a first planar member 12 being a rectangular section or layer of a thin material.

Arranged along a side 14 of the member 12 is a second planar member 16. Second member 16 is also a rectangular section, arranged so that corresponding longer sides 14,18 of each member 12,16 meet. In this way the lengths of the planar members 12,16 are identical. Member 16 is arranged at right angles to member 12 to provide a downstand when member 12 is located horizontally, as is shown in the Figure.

On an opposite edge 20 of the member 12, there is arranged a further planar member 22. Member 22 is parallel to member 16 and perpendicular to member 12. Member 22 is of identical length to the other two members 12,16. Member 22 can be considered to be in two sections, an upper section 24 and a lower section 26. Upper section 24 is an upstand from the first member 12 providing a right angled corner 28 on an upper surface 30 of the member 12. Lower section 26 is arranged as a downstand from member 12 opposite to the downstand provided by member 16. The downstand of lower section 26 is also at right angles to the lower surface

32 of member 12. In this way a cap is formed from the downstands and the member 12 via the corners 34,36.

Isolator 10 is created from sheets of a flexible material formed into the desired shape. The material may be a bituminous/aluminium structure which provides very high acoustic damping and also has high energy absorption characteristics. The material is between 2mm and 5mm thick. Such a thickness not only allows the isolator to be formed easily, it can also bear the load of further structural members and does not extend beyond the typical thickness of a mortar layer.

The isolator 10 could also be created by gluing the members 14,16 together. Other known affixing methods could also be used. Additionally, the material could be a single or multilayered composite material to provide sufficient strength, flexibility and the desired damping characteristics. The material may also be selected to be fire retardant.

Figures 2(c) and 2(d) illustrate an alternative embodiment of an isolator, generally indicated by reference numeral 10a, according to the present invention. Like parts to those in Figures 2(a) and 2(b) have been given the same reference numeral but are now suffixed 'a'. Isolator 10a has identical first and second planar members 12a, 16a as the first embodiment, but now has only an upstand formed by planar member 22a on the opposing side 20a. The upstand 22a is shorter than the downstand 16a. An advantage of this arrangement is that it can be formed from a single sheet of material requiring only two folds at 14a and 20a.

Figures 2(e) and (f) illustrate a further embodiment of an isolator, generally indicated by reference numeral 10b, of the present invention. Like parts to those of Figures 2(a) and (b) have been given the same reference

numeral but are now suffixed 'b'. Isolator 10a has identical first and second planar members 12a, 16a as the first embodiment, but now has only a downstand 22b on the opposing side 20b. The downstand 22b is the same length as the downstand 16b. This arrangement can also be formed by two folds 14b,20b on a single sheet of material. A further advantage of this arrangement is that it forms a cap to grip whatever it is placed over.

Reference is now made to Figure 3 of the drawings which illustrates the isolator 10, as described with reference to Figures 2(a) and 2(b), in use. Figure 3 shows a section of a blockwork construction being a wall-floor joint. It will be appreciated that this may be in a house, apartment or any other type of building construction.

In constructing a blockwork wall for an apartment, for instance, blocks 40a are arranged vertically to provide a wall leaf 42. The blocks 40a are connected by mortar 44 and can be located beside a second wall leaf 46 to provide a cavity wall 48 characterised by the cavity 50 therebetween. When the height is reached for a slab bearing 52 to support a floor 54 in the apartment, the isolator 10 of the present invention is put to use.

Isolator 10 is fitted over the wall head 56. The wall head 56 may be on a load bearing or non-load bearing solid single leaf wall 42. Isolator 10 will have been preformed or may be formed on the site to ensure that the width of planar member 12 matches the width of the wall head 56. In this way the isolator 10 acts as a cap over the wall head 56 with the downstands 16,26 contacting each side 60,62 of the wall head 56 and the corners 34,36 resting thereupon. The isolator 10 is a snug fit so that it remains in place even when left exposed while further elements of the build are put in place. Thus in windy conditions the isolator will remain in

place and prevent adverse health and safety risks which could result from loose material. An adhesive or bonding material may be used to assist in keeping the isolator 10 in place. In the present embodiment, the material used has an abrasive surface which engages with the blockwork surface to ensure the isolator 10 does not move relative to the wall head 56.

The isolator 10 can be arranged over all or some of the perimeter walls i.e. internal and external walls. A number of isolators 10 may be used, with each abutting or overlapping the adjacent isolator to ensure full coverage. Alternatively the isolator 10 may be supplied as a continuous linear strip which is rolled out over the wall head to the desired length where it may then be trimmed to size.

At this point the wall may be levelled if desired. The slab 52 is then lowered on top of the wall head 56. The slab 52 is typically concrete. The slab 52 will ideally bear down upon the upper surface 30 of the isolator to thereby provide a seal. The end 58 of the slab 52 abuts the upstand 24 of the isolator, also providing a seal.

If the slab 52 has a camber and results in a gap being formed between the lower surface 64 of the slab and the upper surface 30 of the isolator 10, this can be filled with mortar 44 or any alternative in-fill to create a wet joint. The mortar 44 will be applied from the right side of the Figure and will be prevented from entering the cavity 50 by the upstand 24. The upstand 24 thus acts as a back plate or stoppage mechanism. A user can thus confidently push mortar into the gap without having to monitor if any is falling into the cavity 50. By filling the gap, air leakage and heat loss through the joint is prevented. By ensuring that no mortar falls into the cavity 50 mortar cannot: collect on wall ties which are present in cavity walls (which can adversely increase sound transmission across walls

leafs) which would require to be cleaned and or removed; fall down to the base of the cavity wall and collect and form an acoustic bridge between wall leafs which would be detrimental for the wall's sound insulation for cavity walls and requires to be cleaned and or removed; or, fall onto the face of the wall, particularly for single leaf walls, and reduce the visual appearance of the wall and require cleaning and removal.

The remaining blockwork 40b,c can be built upon the slab 52 as is known in the art. As the thickness of the planar member 12 is less than that of a normal mortar joint used in masonary or blockwork construction, the isolator does not interfere with the height of the wall 48 or the floor 54. Use of the isolator 10 does not adversely increase the storey height or wall thickness such that other brick or block coursing of other walls 46 is required.

Additionally, the depth of the downstands 16,26 prevents mortar which is inserted into the gap from forming a bridge between the lower surface 64 of the slab and the inner surface 62 of the wall leaf 42. Such bridging would provide a sound and vibration path which would be detrimental to the acoustic performance of the joint.

The insertion of an acoustic isolator 10 between the wall 42 and the floor 54 reduces the transmission of sound and vibration between the storeys of the apartment. The combination of the upstand 24, the planar member 12 and the downstand 16 provides a barrier to air leakage and heat loss through the joint between the room and cavity 50. The upstand 24 can also assist in placing of the slab 52.

As the isolator 10 locates on the wall head, assists in positioning the slab 52 and prevents mortar 44 extruding into the cavity 50, skill is not required

for its use and it can reduce workmanship effects in a build. Indeed the isolator 10 could be prefixed to the wall head to increase ease of use. The isolator 10 is also easily identifiable when in place, making for easier inspection of work completed.

Further arrangements of the isolator 10 are illustrated in Figures 4 and 5. In Figure 4, two leaf walls 42a,b are arranged side by side. While two leaf walls 42 are illustrated, more could be arranged together if desired. A single isolator 10b, having a second member 12b which extends across the wall heads 56a,b and the cavity 50, is located over the wall leafs 42a,b on the blockwork 40a,41a. The side panels 22b, 16b are arranged to fit snugly down over the wall heads 56a,b. In this way isolator 10b effectively caps the wall leafs 42. Once in place, slab bearings 52a,b can be arranged over the isolator with mortar used to seal the joint. Further brickwork, 40b,41b can then be laid to continue the walls as is known in the art. In Figure 5, an alternative arrangement is shown where the wall leafs 42a,b are capped as described for Figure 4, but a floor 53 is now laid over the wall leafs 42. The downstands 16b, 22b act to prevent the passage of sound and vibration from travelling from the leafs 42 to the floor 53.

The principal advantage of the present invention is that it provides an acoustic isolator for incorporation into joints in buildings which reduces sound and vibration transmission at the junction.

A further advantage of the present invention is that it provides an acoustic isolator for incorporation into joints in buildings which reduces air leakage

7 and heat loss through the junction.

A yet further advantage of the present invention is that it provides an acoustic isolator for incorporation into joints in buildings which prevents mortar collecting within a wall cavity, on wall ties or on the face of a wall.

Use of the present invention can also increase the energy rating in apartments.

Modifications may be made to the invention herein described without departing from the scope thereof. For example, any type of joint may be incorporated such as at the point between walls of flats and stairwells. Additionally, though a single isolator is shown at a joint, more than one isolator may be used. In Figure 3, for example, a further isolator can be located on the other side of the slab, under the second storey blockwork. While a single wall head has been capped in the example, the width of the first planar member can be extended to cover any number of wall leafs located together, such as two leafs which form of a cavity wall. The isolator finds equal application in wet or dry joint positions. Due to is very thin nature and high acoustic-vibration damping properties the isolator could also be applied to framed construction such as timber frame, lightweight steel frame, high-rise concrete and steel frame buildings.