GB2512565A

GB2512565A - Stud for a wall and a wall module comprising a stud

Info

Publication number: GB2512565A
Application number: GB201301103A
Authority: GB
Inventors: Stewart Chalmers Dalgarno
Original assignee: STEWART MILNE GROUP Ltd
Current assignee: STEWART MILNE GROUP Ltd
Priority date: 2013-01-22
Filing date: 2013-01-22
Publication date: 2014-10-08
Also published as: GB201301103D0

Abstract

A stud 20 for a wall is disclosed, being elongate and generally C-shaped in section and comprises at least two spaced, elongate stud members 21 to which the wall panels are attached in use and a web member 22 interconnecting the stud members. The web member is provided with a plurality of slots 25 spaced in the longitudinal direction which extend in the longitudinal direction and cut completely through the thickness of the web member. The slots 25 serve to disrupt the transmission path of sound waves travelling transversely across the web member 22, between the stud members 21, and therefore reduce noise transmission from one side of the stud 20 to the other. A wall module comprising a stud 20 and two spaced, parallel wall panels attached to each longitudinal side edge of the stud 20 is also disclosed.

Description

Stud for a Wall and a Wall Module Comprising a Stud The present invention relates to a stud for a wall and to a wall module comprising a stud.

In building construction, stud walls are well-known. They comprise a stud framework to which panels are attached either side forming the exterior surface of the stud wall. The stud framework is often made from wood and usually comprises a number of spaced vertical beams or studs which are attached to top and bottom plates attached to the ceiling and floor respectively. The framework may also include horizontal bars in between each vertical stud as well as other structural components.

Stud wall construction provides a relatively simple, inexpensive structure which is very suitable for internal, non-load bearing walls within a property where strength, security and noise transmission are less of a concern. Stud walls are also suitable for external walls or party walls (shared walls between separate, adjoining properties) but require modification or supplementation to the basic stud wall design.

In the case of a party wall for example, structural properties, security, fire protection and noise transmission need to be taken into consideration. Party walls are typically prone to airborne acoustic noise sources, ranging from a frequency of 50 Hz to 4000 Hz. Most critical noise sources tend to below, bass tone noise sources between 100 Hz and 250 Hz. Noise in this frequency range is emitted from Wand audio devices, which tend to be the greatest source of environmental noise disturbances and complaints between neighbours. Impact noise, whilst needing to be considered, is less of an issue in walls but more important in floor design and construction.

In order to address security and noise transmission considerations, party walls are often made of brick or block construction rather than stud. This type of construction does have some disadvantages, including the need to construct the wall on-site, requiring materials handling and labour supervision. If such a wall is made from a single layer of bricks or blocks, the acoustic and thermal transmission properties are known still to be relatively poor.

Party walls made of two spaced conventional stud walls are known. With insulation installed between and within the two stud walls, thermal properties can be improved compared to block construction. However, this type of party wall construction is relatively thick, depriving the property of available floor area, and is also relatively complex to construct due to the need for two separate stud walls. Fire protection is usually fitted on-site during the construction process, but until this protection is fitted, any fire is likely to spread quickly.

Modular timber construction methods are known, and examples are the "Sigma OP" and "Sigma II" systems produced by Stewart Milne Timber Systems. In these systems, timber-framed modules for the floors, walls and roofs are prefabricated in the factory and delivered to the construction site where they are assembled to form the finished building. As with the conventional twin-stud party wall mentioned above, party walls with the Stewart Milne modular systems have traditionally comprised twin spaced stud wall modules with insulation in between. Although the modular nature of the system reduces the amount of on-site construction which is necessary compared to a conventional twin-stud party wall, there is still some inefficiency due to the need to construct two separate stud walls on-site, insulate between them and fit fire protection. The modular stud party wall suffers from the same relative thickness issue as a conventional stud party wall, and fire spread risk is again high until fire protection is fitted on-site during construction.

The present invention seeks to address the above problems with known construction methods.

In accordance with a first aspect, the invention provides a stud for a wall formed by attaching wall panels to each side of the stud, wherein the stud is elongate and generally C-shaped in section, comprising at least two spaced, elongate stud members to which the wall panels are attached in use and a web member interconnecting the stud members, wherein the web member is provided with a plurality of slots spaced in the longitudinal direction which extend in the longitudinal direction and cut completely through the thickness of the web member.

The presence of the slots in the web member serves to disrupt the transmission path of sound waves travelling transversely across the web member, between the stud members, and therefore reduces noise transmission from one side of the stud to the other. The slots extend in the longitudinal direction at least to some extent, which effectively means that the slots have an angle of less than 90 degrees to the longitudinal direction. It is preferred that they extend more in the longitudinal direction than the transverse direction, in order to increase the disruption of transverse sound waves, and therefore the slots preferably have an angle of about 45 degrees or less to the longitudinal direction. In particularly preferred embodiments, each slot is substantially parallel to the longitudinal direction.

In a preferred arrangement, the plurality of slots define a region of the web member and are configured to provide an effective discontinuity running longitudinally along the length of the region when viewed from the transverse direction. The result of this arrangement is that there is no direct, linear path in the material of the web member transversely across the region (i.e. at 90 degrees to the longitudinal direction). The configuration of slots serves to disrupt and elongate the transmission path of sound waves travelling across the web member, such that the level of attenuation is higher than compared to a direct, transverse path across the region. The non-linear nature of the path which the sound waves are forced to follow is longer, which in itself increases the attenuation, but it is believed that the abrupt changes in direction due to the presence of discontinuities, i.e. slots, across the transmission path further dissipates acoustic energy and attenuates the sound waves.

By reducing the level of acoustic transmission transversely across the stud, a single-thickness wall constructed using the studs of the present invention is suitable for use as a party wall.

In certain preferred embodiments, the presence of the slots in the web member provides an effective cavity within the stud wall which is up to about 40% deeper than the actual depth of the cavity. The invention allows a thinner, single-stud wall to be used which has an acoustic performance equivalent to that of a conventional twin-stud party wall.

The thermal transmission properties of a wall made using the stud of the present invention are also improved. The C-shaped cross-section reduces heat loss compared to a solid stud by having a reduced-thickness web member which lowers the thermal conductivity across the stud. The web member will typically be made from a separate piece of material from the stud members, and the discontinuities between the materials further reduce thermal energy transmission. The arrangement of slots in the web member further reduces thermal conduction transversely across the web member of the stud by effectively lengthening the thermal conduction path.

The region of slots on the web member is preferably centrally located in the transverse direction. In preferred embodiments, the slots run or the region of slots runs along substantially the length of the web member, although it may of course not be necessary or desirable to provide the slots right at the ends, for example if the rigidity or structural integrity of the web member needs to be increased in these areas.

There are various ways in which the slots can be configured to provide an effective discontinuity running longitudinally along the length of the region. For example, a longitudinal line of parallel slots which are angled or inclined to the longitudinal may be provided, with the end of one slot overlapping with the end of the next when viewed from the transverse direction.

In another preferred arrangement, the slots are provided in a plurality of lines running in the longitudinal direction of the web member, and the slots of adjacent lines arranged to be in an offset or overlapping relationship relative to one another to provide the effective longitudinal discontinuity. When viewed from the transverse direction, the slots of one line lie across the spaces between the slots of the adjacent line.

In an offset-type arrangement, the transmission path of sound waves travelling through the web member in a transverse direction from one stud member to the other is non-linear. The slots of adjacent lines may also be configured such that there is no direct line of web member material at all angles to the transverse direction across the web, between one stud member and the other. The terms non-linear and non-direct are intended to cover any shape of path other than a straight line, including curved, angled, staggered and tortuous.

As discussed above, the slots extend in the longitudinal direction at least to some extent. In one embodiment in which the slots are arranged into a plurality of longitudinal lines, the slots are parallel slots which are angled or inclined to the longitudinal. The slots of adjacent lines may be angled in the same orientation, or in the opposite orientation so as to form a herringbone pattern.

In another embodiment in which the slots are arranged into a plurality of longitudinal lines, the slots are preferably substantially parallel to the longitudinal direction as are the lines of slots. Preferably, the slots within the same line are of uniform length and are uniformly spaced. More preferably, the slots of all lines have the same length and the same spacing.

In a preferred arrangement which maximises the minimum transmission path length for a given slot length and spacing, the slots of adjacent lines are offset by about 50% relative to each other, or in other words, by about half the repeat distance of the slot pattern.

Within each line of slots, the greater the length of a slot compared to the combined length of a slot and a spacing, the greater the transmission path length. Preferably, the length of a slot compared to the combined length of a slot and a spacing is about 50% or greater. At the other end of the range however, if the amount of solid material between the slots is reduced too far, the stud may become prone to collapse when under transverse compression, such as during stacked transportation or storage when pre-formed into a wall module (discussed further below). Preferably therefore, the length of a slot compared to the combined length of a slot and a spacing is no greater than about 90%. Preferred ranges for the length of a slot compared to the combined length of a slot and a spacing are 50-90%, 60-90%, 70-90% and 80-90%.

In preferred embodiments, at least two lines of slots are provided on the web member. In practice, three lines of slots have been found to work well, however four, five or more lines may also work well and would provide increased acoustic and thermal separation. However, with increasing numbers of lines, care must be taken to ensure the structural integrity of the web member is not compromised, particularly when the stud is subject to transverse compression.

As mentioned above, the lines of slots run along the web member substantially in the longitudinal direction. The lines of slots do not need to be exactly parallel, but should be generally parallel; in practice, it is likely that the lines will be substantially parallel as a result of practical, high-volume manufacturing techniques.

In any slot configuration within the scope of the invention, suitable dimensions for each individual slot and the spacing between slots (and lines of slots) will be apparent to the skilled person based on practical considerations, such as the overall dimensions of the stud and the properties of the web member material. In preferred embodiments, the length of a slot is between 100mm and 450mm and the width of a slot is between 1mm and 5mm. The spacing between slots within the same line may be between 25mm and 100mm. A particularly preferred arrangement has a slot length of 200-250mm, a slot width of 3-5mm and a spacing within a line of 25-50mm. The spacing between each line of slots (i.e. in a transverse direction) may preferably be between 10mm and 50mm. A particularly preferred line spacing is between 15mm and 25mm.

S The slots may be pre-formed in the web member, but it is more likely that the slots will be cut into the sheet web material during manufacture. While there are many suitable methods for cutting the slots into the web material, a preferred embodiment employs a circular saw or router device. In this case, any practical manufacturing arrangement is not likely to pass the circular saw through the web to at least its radius depth, and therefore the slots will not be square-cut at their ends but will have a curved profile following the curve of the saw blade. For safety reasons, it may be preferable for the saw blade to only marginally break the distal surface of the web, in which case the curved profile may be more prominent.

The stud members and web member may be made of any suitable material, including metal or plastics, but preferably they are made of wood. In cross-section, the stud may be made from a single, appropriately-shaped piece of material (which is supplied in lengths), but in reality and particularly when using wood, a more efficient arrangement will employ separate components for the stud members and web member. In a preferred arrangement, the stud members are made from timber and the web member is made from a wood-based panel (such as ply, hardboard, medium-density fibreboard (MDF), oriented strand board (OSB), or the like) or from any suitable structural sheathing material. Non-wood materials from which the web member could be made include reinforced gypsum, cement particle, magnesium oxide or calcium silicate.

The transverse width of the stud (and therefore the spacing between the wall panels) may be of any suitable dimension for the specific application. Two preferred standard widths which the applicants envisage are about 195mm and about 235mm.

The web member does not necessarily extend across the full width of the stud but could overlap only partially with the stud members at each side. Alternatively, the web member could extend between but not overlap with the stud members, provided some means of attaching the components together is provided (unless the stud is made from a single piece of material). Preferably however, the web member extends the full width of the stud, and therefore in the preferred stud embodiments mentioned above, the web member would have a width of about 195mm or about 235mm respectively. The thickness of the web member may be between 5mm and 20mm, with a preferred thickness being about 8-10mm or about 9mm.

The side of the stud members to which the wall panels are attached may be any suitable width to provide a sufficient attachment surface. This width may range from about 30mm to about 100mm, or about 35mm to about 90mm. A particularly preferred with is about 35- 40mm with a value of 38mm being a standard width. In total, including the thickness of the web member, the side width of the stud will therefore be about 50mm in particularly preferred embodiments.

In the transverse direction of the stud, each stud member may have a depth of between about 40mm and about 150mm or between about 40mm and 100mm. A preferred depth is about 60mm. If the stud width/depth is about 195mm, a stud member depth of about 60mm divides the transverse width into three approximately equal sections (stud member -web member (only) -stud member).

Each stud member may be square or rectangular in cross-section. If rectangular, the longer side may be parallel to the plane of the web member or it may be perpendicular to it. This provides the option of a smaller or larger attachment surface for the wall panels and larger or smaller interface with the web member, depending on the particular requirements of the construction.

Studs in accordance with the invention may be constructed using multiple stud members and/or multiple web members depending on the need for increased strength and rigidity compared to a standard stud formed from two stud members and a single web member.

Increased strength and rigidity may be required if the wall is to bear an increased load, for example. Increased rigidity and resistance to sideways flexing may be advantageous where walls meet, for example where a wall constructed using a stud in accordance with the invention meets an external wall. Various stud configurations are discussed below.

A stud in accordance with the invention may be constructed using two or more stud members. For example, more than one stud member may be provided on each side of the stud. Additional stud members may be provided adjacent to the first stud member on the same side of the web member (effectively lengthening the arms of the C-shaped cross-section) and/or on the other side of the web member from the first stud member (effectively creating an H-shaped cross-section). The stud members, if rectangular in cross-section, may be oriented in the same or in orthogonal directions. For example, stud members on one side of the web member may have their longer sides parallel to the plane of the web member and on the other side of the web member their longer sides may be perpendicular to the plane of the web member.

A stud in accordance with the invention may comprise one or more web members. If two or more web members are employed, they may be positioned adjacent to one another (effectively forming a double, triple, etc. web member) or the web members may be spaced from one another and have one or more stud members in between. Further stud members may be provided on one or both of the outside faces of the web members.

A stud is typically used to refer to a vertical beam to which a wall panel is to be attached, and that also applies in relation to the present invention as described. However, the stud of the present invention may instead, or in addition, be used in a horizontal orientation or in any other orientation. The skilled person will understand that the relative orientation in which the stud of the present invention is used in practice will not affect the benefits provided by the invention.

In a preferred embodiment, the stud of the present invention may be used as a rail, or horizontal beam. The stud of the present invention can also be used in a combination of both vertical and horizontal orientations, for example as the four sides of a wall module discussed further below. In the case where the stud is used horizontally as a rail, it may be necessary depending on the situation to seal or cover the slots to prevent damp or water ingress to the core of the wall or module. Self-adhesive weatherproof tape is suitable for this purpose.

In accordance with a second aspect, the invention provides a wall module comprising at least one stud as described above and two spaced parallel wall panels attached to each longitudinal side of the stud. The stud therefore extends between the two spaced wall panels, and preferably its transverse direction is substantially perpendicular to the planes of the parallel panels.

Preferably, the module includes at least two studs for structural stability. Although they can be any shape including angled, the wall panels on each side of the module will in most cases be quadrilateral (i.e. rectangular or square) and of the same dimensions, and a preferred arrangement is to align the panels so that they overlie when viewed in the transverse direction to form a module with two pairs of opposing side edges (vertical and horizontal in use). A stud is preferably located at each side edge of at least one pair of opposing side edges, which would usually be the vertical side edges in use. However, studs may alternatively or in addition be provided along each opposing horizontal edge, effectively forming top and bottom rails in the module. With studs and rails around the perimeter of the module, a strong, box-like structure is achieved. A particularly preferred module will include one or more studs located intermediate the side edges of the module, usually parallel to the two vertical edge studs.

In order to increase the sound insulation properties of the panel, it is preferable to include sound-absorbing material in the void spaces inside the wall module. Any suitable material may be used for this purpose, although it is preferably fire retardant. A preferred material is glass fibre, which has good sound absorption properties, such as 200mm or 250mm glass wool insulation having a density of about 18 kg/rn3. The applicants have found that a relatively compact fill with glass fibre (e.g. by using more than one layer of glass fibre matting) further improves sound insulation by limiting the potential for any gaps or voids to remain.

Each wall panel of the wall module may be unitary, formed of a single sheet of material, or it may be formed of a plurality of sheets of material. The material of the wall panel may be any suitable material for the purpose, including most types of board including plasterboard.

However, through extensive research, the applicants have discovered that the use of varying densities of material in the module assists sound absorption by disrupting the acoustic wave path. Preferably therefore, the material used for the wall panels is a relatively dense material compared to the material used for the studs. As mentioned above, the studs are preferably made of wood, which typically has a density in the range of 300-450 kg/m3.

Preferably, the density of the panel material is at least about twice that of the stud material, but more preferably at least about three times that of the stud material. In preferred embodiments, the panel material has a density in the range of about 900 kg/m3 up to about 1400 kg/m3.

A particularly preferred material for the wall panels is non-combustible sheathing. This can be formed using calcium silicate, magnesium oxide, reinforced gypsum or cement particle board formulations. A suitable proprietary material is V-Wall board made by RCM Ltd. V-Wall board is made from a mix of cement, lime, calcium silicate, wood fibre and additives to form a very dense, solid material. Its typical density is 1200 kg/m3 which is about 3 times denser than timber sheathing board and about 10 times denser than plasterboard. It is comparable with a dense masonry block.

The use of this type of sheathing board also reduces the risk of fire, which is a particular concern during construction while the final plasterboard fire protection layer is not fitted.

The sheathing board provides fire compartmentation during construction, helping to reduce fire spread between construction zones or to adjacent buildings. The board also reduces radiant heat emission and potential damage to nearby buildings. The board is very strong and highly weather resistant, which is particularly beneficial during storage, transportation and construction, before the building is weather-tight.

The basic structure of a wall module in accordance with at least preferred embodiments of the invention, which can be constructed off-site, comprises the studs, wall panels and void insulation as required. The modules can be transported to the construction site and fixed vertically in position adjacent to other modules or other walls to form the building structure.

Once the modules are in place, the structure can be completed by adding the surface finishing panels (e.g. plasterboard) and services as required.

In a further development, the applicants have found that the provision of a relatively small cavity between the wall module panel and the surface finishing panel further reduces acoustic transmission. Such a "micro cavity" is preferably up to about 5mm, and more preferably within the range of about 1-3mm, or ideally about 3mm.

While not wishing to be bound by any particular theory, it is believed that the micro cavity allows the plasterboard finishing panel to vibrate at a frequency which is different to that of the inner, more dense sheathing panel. The inner sheathing panel is more rigid and more securely fixed into position and creates a rigid skin, whereas the plasterboard has the potential to "trampoline" and help to break up the noise path and absorb acoustic energy.

Preferably, the cavity is formed by the placement of spacers between the wall module panel and the surface finishing panel, the thickness of the spacer being the desired cavity depth.

The spacers are preferably resilient. In a preferred embodiment, the spacers comprise a plurality of spaced strips of material which overlie the stud edges. This will provide a more solid attachment for the surface finishing panels, through the spacer strips and the wall module panels, directly to the studs. The wall module panels and surface finishing panels can be attached to the studs (and rails) directly or indirectly by using any suitable fastener, such as nails, screws or the like. In the case of the surface finishing panels, the attachment to the studs and rails will be indirect, via the wall panels and spacers, if present.

In order to assist with assembly and to provide additional acoustic damping, the spacers are preferably self-adhesive. A preferred material for the spacers is an acoustic resilient strip (ARS) made from a self-adhesive bitumen-based material with a gelling agent, available from Icopal Limited. The spacer strips are preferably about 50mm wide and run the vertical length of the studs, overlying them. They may conveniently be attached to the wall module during off-side manufacture of the module.

The surface finishing panels can be formed from any suitable material as desired. In most cases, it is expected that plasterboard will be the chosen material and the wall modules have been designed with this material in mind. A preferred type of plasterboard is 15mm type A taper-edged sound-shield wallboard, made by Knauf and having a density of 14 kgjm3.

Although the present invention is particularly beneficial when used in or as a single-stud party wall, it is suitable for use in other locations, such as external walls, internal walls, load-bearing walls, non-load bearing walls and room divider walls.

In summary, the present invention provides a stud and a wall module having improved acoustic insulation properties compared to the prior art. A wall constructed with the present invention can be thinner and less complex, allowing material and labour cost savings to be achieved, as well as an increase in usable floor area.

The invention also extends to a wall for a building, such as a party wall, comprising at least one stud as described above or at least one wall module as described above. A building including such a wall is also an aspect of the invention.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 shows a perspective, partial cross-sectional view of a wall module incorporating studs and rails in accordance with the invention; Fig. 2A shows an elevation of a stud in accordance with the invention; Fig. 2B shows an end view of the stud of Fig. 2A (not to scale with Fig. 2A); Fig. 3 shows alternative stud constructions to that of Fig. 2B, in accordance with the invention; Fig. 4 shows a horizontal cross-sectional view of a party wall constructed using a wall module in accordance with the invention; Fig. 5 shows a horizontal cross-sectional view of a party wall constructed using a wall module in accordance with the invention, including a service zone; Fig. 6 shows a vertical cross-sectional view of the junction between mid-floor modules and upper and lower party walls constructed using wall modules in accordance with the invention; and Fig. 7 shows a horizontal cross-sectional view of the junction between a single-skin party wall constructed using a wall module in accordance with the invention and an external wall.

Fig. 1 shows a wall module lOin accordance with a preferred embodiment of the invention in partial cross-section. Wall module lOis shown mounted on a typical ground floor construction comprising ground floor slabs 1 and a block upstand 2. A soleplate 3 is fixed to the block upstand and serves to locate the wall module 10 as will be described below. Foam seals 4 may be provided to seal the junction between the wall module 10 and the block upstand 2, and slab insulation 5 may be provided between the floor slabs 1 and block upstand 2. Other types of floor construction, whether ground-floor or mid-floor, are of course suitable for use with the present invention.

Wall module 10 comprises front vertical face 11, rear vertical face 12, left side 13, right side 14, top side 15 and bottom side 16. Wall module lOis formed from a number of vertical studs 20 and horizontal rails 30, both being of the same general construction which is described in more detail below. It can be seen in Fig. 1 that the studs 20 and rails 30 are generally C-shaped in section. Elongate, vertical studs 20a and 20b form the left and right sides 13 and 14 of the module respectively and horizontal rails 30a and 30b form the top and bottom sides 15 and 16 respectively. An intermediate vertical stud 20c is also provided in between the two side studs, approximately equidistant between the two.

As can be seen from Fig. 1, left and right side studs 20a and 20b are positioned with their C-shaped sections oriented inwards whereas the top and bottom rails 30a and 30b are positioned with their C-shaped sections oriented outwards. This arrangement firstly simplifies the assembly of the module since a complex corner joint potentially requiring one or both components to be cut is avoided. Secondly, no large gaps to the interior of the module are left at the corners. Thirdly, and most conveniently, top and bottom rails 30a and 30b provide a central channel 17 which can be used to ensure the module is located and fixed in the correct position. As mentioned above, soleplate 3 which is fixed to block upstand 2 locates in the central channel 17 during installation of the module. The module can then be fixed in place to the soleplate by means of suitable fixings provided horizontally through the top and bottom rails 30a and 30b.

With the general arrangement of studs and rails as described, the assembly of module lOis completed off-site by the addition of sound insulation material 40 such as fire-retardant glass fibre matting and wall panels 50 such as the relatively dense, non-combustible calcium silicate sheathing board referred to above. Vertical spacing strips 60 formed of acoustic resilient material are attached to wall panels 50, also usually as part of the off-site module manufacturing process. The spacing strips are attached to the wall panels 50 where the panels overlie the studs 20. Once the module is fixed in location on site, surface finishing panels 70 such as plasterboard are attached to the modules forming the wall, with the spacing strips 60 forming micro-cavities in between the wall panels 50 and the surface finishing panels 70 as described above. It is preferable to ensure that the vertical joins between sections of surface finishing panels do not line up with the vertical joins between modules, so that any gaps are staggered and any risk of noise transmission through the gaps minimised.

Figs. 2A and 2B show the construction of a stud 20 or rail 30 in more detail. Reference will be made to a stud for conciseness, but the structure is equally applicable to a rail. Stud 20 is formed from two parallel, spaced elongate timber stud members 21 which are connected by a planar web member 22 formed from oriented strand (OSB). The web member 22 is attached to the stud members 21 by means of nails or staples.

Web member 22 is provided with a slotted region 23 which is located centrally, in the region of the web member between the two stud members, and which runs the full longitudinal length of the web member. Slotted region 23 contains three longitudinal, parallel lines 24 of slots. The individual slots 25 are also parallel to the longitudinal direction. All of the slots 25 have the same length and spacing within each line. Adjacent lines of slots are offset in the longitudinal direction by 50% relative to one another.

Fig. 3 shows examples of alternative stud constructions to that of Fig. 2B which are still in accordance with the invention. Fig. 3A shows a "rotated" stud in which the rectangular-section stud members 21 are rotated by 90 degrees compared to the standard stud of Fig. 2B, so that their longer sides are perpendicular to the plane of the web member 22. The "rotated" stud provides a larger attachment surface for the wall panels. Fig. 3B shows a "hybrid" stud which is essentially a combination of a standard stud and a rotated stud. This type of stud provides increased strength both in terms of load-bearing capability and lateral rigidity, as well as a larger attachment area for the wall panels. An example of where a hybrid stud may be used is given below in Fig. 7, where a party wall constructed in accordance with the invention meets an external wall.

Fig. 3C shows a stud built up from multiple stud members 21 with a single web member 22 and Fig. 3D shows a stud built up from multiple stud members 21 and multiple web members 22. These arrangements also provide increased strength compared to the standard stud.

Turning to Fig. 4, this drawing shows a horizontal cross-sectional view of a section of party wall constructed using the wall module of Fig. 1. One intermediate stud 20c is shown in this view, to which calcium silicate sheathing wall panels 50 are attached either side. Glass fibre matting 40 fills the void spaces inside the module. Vertical spacing strips 60 formed of acoustic resilient material are attached to wall panels 50 at locations corresponding to the studs 20. Plasterboard surface finishing panels 70 are fixed in place on site.

Fig. 5 shows a similar view to the party wall section of Fig. 3, but with the addition of a service zone 80. Service zone 80 allows pipes, cables, etc. to be hidden from view in a void space created between surface finishing panel 70 and a further finishing panel 81, which may also be formed from plasterboard. Finishing panel 81 is mounted to a series of battens 82 which are attached to the surface finishing panels in alignment with the studs 20. In some applications, it may be possible for inner finishing panel 70 to be omitted and the battens 81 fixed directly to wall panels 50.

Fig. 6 shows an elevational view of a vertical cross-section of the junction between mid-floor modules and upper and lower party walls constructed using wall modules described above.

The drawing shows two mid-floor modules 90 mounted on top of lower party wall module 1OL. Upper party wall module lOU is mounted on top of the two mid-floor modules 90, straddling the join between them. The four modules are fixed together using long screws 91 which are inserted through each corner intersection at an angle of approximately 45 degrees.

Therefore, each screw 41 secures one wall module and one mid-floor module together.

The adjoining ends of each mid-floor module 90 are sealed with an air-tight membrane 92 and a strip of Rockwool® slab insulation 93 is fitted between the ends of each mid-floor module on site. Acoustic seals 94 are fitted to the top surface of lower wall module 1OL and to the bottom surface of upper wall module lOU. A suitable material is made by Vita Cellular Foams (UK) Ltd. under the trade name Flexitec. Skirting 95 is fitted on-site to the lower edge of upper wall module lOU.

Fig. 7 shows a plan view of a horizontal cross-section of the junction between a single-skin party wall 100 in accordance with the invention and an external wall 200. Module 100 is a modified version compared to that described above as it includes an additional "hybrid" stud in order to provide further strength and rigidity at the point where the party wall and the external wall meet.

External wall 200 is constructed from wall modules 201 and outer leaf 202. External wall modules 201 are similar in construction to wall modules of the invention apart from the fact that the studs 203 do not need to be slotted, although of course they could be if desired or expedient. External leaf 202 will typically be constructed from bricks or blocks 204 and optionally provided with an external finishing layer such as cement render 205. An expansion joint 206 is provided in external leaf 202, at the location of the party wall 100.

Acoustic seals 207 are fitted between external wall modules 201 and party wall module 100.

These may be pre-fitted to the ends of external wall modules. Vertical strapping 208 is fitted in the junction corners and this may also be pre-fitted to the external wall modules 201. The three modules are fixed together using nails or screws 209 as appropriate. Finally, surface finishing panels 210 are attached to the modules, ready for skimming and painting as required.

Claims

Claims 1. A stud for a wall formed by attaching wall panels to each side of the stud, wherein the stud is elongate and generally C-shaped in section, comprising two spaced, elongate stud members to which the wall panels are attached in use and a web member interconnecting the stud members, wherein the web member is provided with a plurality of slots spaced in the longitudinal direction which extend in the longitudinal direction and cut completely through the thickness of the web member.
2. The stud of claim 1, in which the plurality of slots define a region of the web member and are configured to provide an effective discontinuity running longitudinally along the length of the region when viewed from the transverse direction.
3. The stud of claim 2, in which the region of the web member is centrally located in the transverse direction.
4. The stud of claim 2 or 3, in which the region of the web member runs along substantially the length of the web member.
5. The stud of any preceding claim, in which the plurality of slots are arranged into a plurality of lines running in the longitudinal direction of the web member.
6. The stud of claims, in which at least three parallel lines of slots are provided on the web member.
7. The stud of claims or 6, in which each slot is substantially parallel to the longitudinal direction.
8. The stud of claim 5,6 or 7, in which the slots of adjacent lines are offset in the longitudinal direction relative to one another.
9. The stud of claim 8, in which the slots of adjacent lines are offset by about 50% relative to one another.
10. The stud of any of claims 5 to9, in which the slots are of a uniform length and a uniform spacing within each line, and in which the length of a slot compared to the combined length of a slot and a spacing is between about 50% and about 90%.
11. The stud of any preceding claim, comprising more than one stud member on each side of the stud.
12. The stud of claim 11, in which the stud members on each side of the stud are adjacent to each other, on the same side of the web member.
13. The stud of claim 11, in which the stud members on each side of the stud are located either side of the web member.
14. The stud of any preceding claim, comprising more than one web member.
15. The stud of claim 14, in which one or more stud members are located in between each web member on each side of the stud.
16. A wall module comprising at least one stud as claimed in any preceding claim and two spaced, parallel wall panels attached to each longitudinal side edge of the stud.
17. The wall module of claim 16, in which the wall panels are quadrilateral and are aligned to form the module with two pairs of opposing side edges, a stud being located at each side edge of at least one of the pairs of opposing side edges.
18. The wall module of claim 17, in which studs are located at each side edge of the module.
19. The wall module of claim 17 or 18, in which one or more studs are located intermediate the side edges of the module.
20. The wall module of any of claims 16 to 19, further including sound-absorbing material in void spaces inside the wall module.
21. The wall module of any of claim 16 to 20, in which the wall panels are made from a relatively dense material compared to the material used for the at least one stud.
22. The wall module of claim 21, in which the wall panels are made from sheathing board.
23. The wall module of any of claims 16 to 22, in which the wall module includes one or more surface finishing panels attached to the wall panels.
24. The wall module of claim 23, in which a cavity is provided between the wall panel and the surface finishing panel by placing spacers between the panels.
25. The wall module of claim 24, in which each spacer comprises a strip of acoustic resilient material.
26. A wall comprising at least one stud as claimed in any of claims ito 15 or at least one wall module as claimed in any of claims 16 to 25.
27. A building including a wall as claimed in claim 26.
28. A stud for a wall substantially as described herein with reference to the accompanying drawings.
29. A wall module substantially as described herein with reference to the accompanying drawings.