The present invention relates to a wall construction for a building, the wall construction comprising a wooden structural frame and a method of manufacturing same. More particularly, the invention relates to a wall construction in which the structural frame includes a vapour barrier.

To reduce heat exchange between an inside and an outside of a building, the authorities in some countries have regulations for the insulation of walls, floors and roofs. The description that follows will substantially be directed towards an external wall of a building.

To reduce the energy consumption for tempering buildings, the requirements for insulation have increased considerably over the last 20 years. The insulation is typically installed in the wooden structural frame which includes vertical studs spaced apart and fixed to bottom and top plates.

A person skilled in the art will know that the purpose of the vapour barrier is to prevent humid air from reaching its dew point in the wall construction. One of the purposes of the vapour barrier is thus to avoid the formation of moisture in the wall. Such moisture formation could result in an increase in the heat transfer coefficient, the so- called U-value, of the wall construction, which in itself is not very desirable for energy- economy reasons. However, moisture formation in a structural frame represents a more serious problem, namely fungus and rot.

The risk of such condensation depends on many factors, but in the building trade in Norway the problem is considered to be real as long as the thickness of the insulation is over 200 mm.

A vapour barrier that is correctly installed on a so-called "warm" side of a structural frame, that is to say on the side of the structural frame of an external wall that faces the inside of the room, may prevent air from moving from the warm side into the insulation, where it will condense if the air is cooled to its dew point. However, experience shows that it is challenging to achieve a completely tight vapour barrier, that is to say a vapour barrier without any leakage openings. This is due to, among other things, the fact that it may be problematic to seal around pipes, cables, junction boxes and the like that are extended through the vapour barrier, or perforation of the vapour barrier in consequence of damage arising in the building period before the vapour barrier is protected by internal wall cladding. According to the prior art, the vapour barrier is interrupted through joisting or floors.

To reduce the problems mentioned, it is usual today to install the vapour barrier in a "set back" manner in the wall construction, typically at 1/4 from the warm side of the wall. This is achieved by installing the vapour barrier on the inside of the structural frame as before, and by a furring or casing being installed on the outside of the structural frame so that the vapour barrier is between the structural frame and the furring. In the specialist environment, said furring is also referred to as "boxing". Thus, a space is provided between the vapour barrier and the inside wall cladding, this space being suitable for housing pipes, cables and junction boxes, for example.

Another challenge with today's building method is that a wall construction with a correctly installed vapour barrier will be very tight. A tight wall which, in addition, has a thick layer of insulation, maybe thicker than 300 mm, will result in stagnant air in the structural frame. Of course, this is an advantage as long as the structural frame is dry when the construction is being assembled. However, a great number of wall constructions are built in situ and are thereby exposed to precipitation in the building period. Research shows that a moist structural frame that has insulation and a vapour barrier applied to it may stay moist for several years after the building has been completed. The risk of fungus and rot damage arising in the structural frame is therefore high. The problem can be reduced by letting the wall construction stay open for as long as possible in the building period after the building has been sealed externally with a roof and external cladding. So-called building dryers may be used in addition to facilitate or expedite the drying. However, such a drying period could delay the progress of the building process while, at the same time, a building dryer requires very much energy.

From the publication JP H1030281 A, a wall construction is known, in which a conventional vapour barrier between an internal wall cladding and a structural frame has been replaced by a plate-shaped body made from a moisture-absorbent and moisture- releasing acoustical-insulation material. The plate-shaped material rests against an insulation material in the structural frame. On the outside of the structural frame, a diffusion-open, waterproof cloth is installed, which is clamped against the structural frame by means of laths that support the external cladding of the wall construction. The wall construction known from JP H1030281 A is thus diffusion-open.

Such a diffusion-open wall construction may, by great temperature differences between indoor air and outdoor air, cause condensation in the insulation, especially if the insulation thickness exceeds 200 mm. Thus, the diffusion-open solution described in JP H1030281 is not suitable where an insulation thickness of more than 200 mm is required in order to satisfy the existing requirements for thermal insulation in buildings.

From the publications JP H11293801 A and JP H08260586 A, wall constructions for ensuring airing of the back of the external cladding of the wall are known. In JP H11293801, a watertight barrier is clamped between the back of the cladding and the framing studs of the wall construction. Air is flowing between the waterproof barrier and insulation installed between the studs. In JP H08260586 a waterproof, but diffusion-open, cloth is installed on the outside of the structural frame.

The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through the features that are specified in the description below and in the claims that follow.

The inventor has surprisingly found that the challenges of moisture in the structural frame, whether caused by leakage in the vapour barrier or moisture forming in the building period, can be solved in a simple manner by "moving the structural frame into the warmth"; that is to say, the structural frame is exposed to a climate inside the room defined by the wall construction among other things.

The invention is defined by the independent claims. The dependent claims define advantageous embodiments of the invention.

According to a first aspect of the invention, a wall construction for a building is provided, the wall construction comprising a wooden structural frame, the structural frame at least comprising vertical studs which are fixed, at their end portions, to plates at the top and bottom, and the structural frame constituting at least a portion of a wall that has an external side and an internal side. The characterizing feature of the invention is that the external side of the structural frame is provided with a vapour barrier. By the term "external side" is meant, in this document, the side of the structural frame that is predominantly exposed to the lowest temperature of the wall construction, typically an outdoor temperature. In this document, the external side will also be referred to as the "cold side".

By the term "vapour barrier" is meant, in this document, a material which is diffusion- tight or vapour-tight in at least one direction, and that the at least one direction is from a "warm side" towards a "cold side". A common type of vapour barrier used in the building industry is made of an ageing-resistant plastic material which is diffusion- tight in both directions.

By installing the vapour barrier on the external or cold side of the wall, the structural frame will be exposed to the indoor climate of the building. Any moisture in the structural frame will thereby be vented to the indoor climate. In addition, the risk of damaging the vapour barrier in connection with the installation of hidden systems such as pipes and cables will be considerably reduced. The above-mentioned casing or boxing will not be necessary either.

The wall construction may further comprise a framework projecting substantially at right angles from the external or cold side of the structural frame.

The framework may comprise a plurality of frames made of wood, for example, the frames being spaced apart along a longitudinal direction of the wall construction. Each of the frames may typically be fixed to the framing studs of the wall construction.

In one embodiment, each of the frames includes a first lath fixed to the structural frame, and a second lath installed at a distance from the first lath by means of a spacer.

One of the purposes of the framework is the ability to house an insulation means such as mineral wool. A person skilled in the art will know that the purpose of such an insulation means is to prevent, to the greatest extent possible, the motion of air and that it is therefore very important to prevent open "air channels" between, for example, what is housing the insulation means, which is the framework here, and the insulation means. The person skilled in the art will also know that even though an insulation means is relatively flexible, it has a "minimum bend radius", so that said air channels may form if the insulation is pressed against elements that have a size that compresses the insulation and a design with sharper edges than the minimum bend radius of the insulation. To reduce the risk of said air channels, a very accurate cutting is required for an insulation means that is installed against an element. Such a cutting is time-consuming and may be challenging to get sufficiently accurate.

As mentioned above, one of the purposes of the framework is to house the insulation means. Another purpose is to support the external cladding of the wall construction. It will thus be understood that the framework only needs to be dimensioned for carrying relatively small loads. However, the spacer used in the framework must have a certain strength in order to, among other things, ensure load transmission from the outer portion of the framework, which may be said second lath, to the inner portion of the framework, which may be said first lath.

A person skilled in the art will know that wood has a far higher thermal conductivity than an insulation means of a kind known per se, such as mineral wool. Wood that extends through an insulation means may thereby cause a cold bridge.

To reduce the cross-sectional area of the spacer, in order thereby to achieve a reduced cold bridge as well, the spacer may, in a position of application, have a vertical section exhibiting a height that is larger than the width of the spacer. By width is meant, here, the extent parallel to the horizontal extent of the wall construction. The spacer may thus be a plate-shaped element which has a height that, in the position of use, is larger than the thickness of the plate.

An insulation means of the above-mentioned kind, which is installed between the spaced-apart frames of the framework, will have to abut against the spacers. In one embodiment, a side face of the insulation means may be installed sealingly against a first side face of the spacer. However, any further insulation means that might be installed against a second side face opposite the first side face will also have to cover the side faces that make up the width or thickness of the spacer. In order to at least reduce the problem of said air channels, it may be practical if the spacer is formed with a first side face and a second side face, the length of the first side face being different from the length of the second side face. Thus, the first side, for example, may be straight, whereas at least a portion of the second side face may be formed with a concave portion or a polygonal portion. Regardless of design, the purpose is to produce a spacer in which the side (or the sides) of the spacer against which the insulating means is compressed has a design adapted to the "minimum bend radius" of the insulation means, so that said air channels are avoided to the greatest extent possible.

It will be understood that even if the wall construction is insulated with an insulation means installed in the framework as explained above, a further insulation means may be installed in a space defined between each of the studs of the framing studs and the top plate and bottom plate of the structural frame. Thus, the further insulation means will improve the U-value of the wall construction, while, at the same time, it will have a favourable sound-proofing effect. The further insulation will be separated from the inside of the room by means of a cladding, such as panelling, or a building board of a kind known per se.

According to a second aspect of the present invention there is provided a module system comprising at least two wooden module elements to provide a portion of a wall construction which has an external or cold side and an internal or warm side, each of the module elements including a structural frame with a periphery surface, the structural frame comprising at least two vertical studs which are fixed, at their end portions, to horizontal plates, and the module elements being arranged to be attached to each other, the structural frame of each of the module elements being provided with a vapour barrier installed against the external side of the structural frame.

In an alternative embodiment there is provided a module system comprising one wooden module element to provide a wall construction that has an external or cold side and an internal or warm side, the module element comprising a structural frame with a periphery surface, the structural frame comprising at least two vertical studs which are fixed, at their end portions, to horizontal plates, and the module element being arranged to be attachable to module elements of adjacent wall portions, the structural frame of the module element being provided with a vapour barrier installed against the external side of the structural frame.

The module element or module elements may typically be produced in a factory building. Thereby, arrangements may be made for efficient production in a controllable and predictable climate. By doing so, the challenges with respect to precipitation and wind in connection with the production of the module elements will be eliminated.

Two or more module elements may be placed side by side or at least partially over each other to produce a wall construction.

In an embodiment of the module system in which it comprises only the structural frame before two module elements are connected to each other, it may be an advantage if the vapour barrier of at least one of the module elements has an extent which is larger than the extent of the module element. The vapour barrier of a first module element will thereby overlappingly be brought into abutment against a second module element after they have been connected to each other side by side or over each other. Thereby an effective vapour barrier is ensured at the interface between two interconnected module elements.

As will be explained below, in a preferred embodiment of the module system according to the present invention, it will be desirable to manufacture the module elements as completely as possible before they are connected to each other. In such an embodiment, it is an advantage if a marginal area of the vapour barrier is installed against the periphery surface of the structural frame. By a periphery surface is meant, here, the edge faces of the module element that define the extent of the module element. In a position of use, the periphery surface may thus be the side faces of the studs and plates facing away from a centre portion of the module element.

The vapour barrier may be fixed to the periphery surface by means of staples and/or an adhesive. To ensure a best possible seal between the vapour barrier and the periphery surface of the module element, the spacing of the staples must be as small as possible, for example 10 cm or less. Fixing the vapour barrier to the periphery surface of the module element is thus time-consuming. Using a curable adhesive can be messy and the application time-consuming. In addition, such an adhesive may require a certain time before achieving its intended effect, namely to connect the vapour barrier to the periphery surface of the module element. An adhesive means in the form of sticky tape is relatively quick and easy to apply; at the same time, it achieves its function immediately.

Independently of which one or which ones of the above-mentioned fastening means will be used, providing a seal at the interface between two adjacent module elements will be a challenge.

To ensure a substantially complete seal between the vapour barrier and the periphery surface of the module element and, at the same time, a seal between two adjacent module elements, it is an advantage if the vapour barrier is wedged, by means of a vapour-proof strip, to a groove arranged in the periphery surface. The strip is com- plementarily adapted to the width of the groove, but is larger than the depth of the groove so that, in a position of use, the strip protrudes a short distance from the periphery surface. "A short distance" may be, for example, 1-5 mm. Thus, the periphery surface of the structural frame of the module element may be provided with grooves arranged to receive the marginal area of the vapour barrier and a complementarily adapted sealing strip arranged to clamp the vapour barrier to the groove.

As will appear from the description below, such a groove and such a sealing strip may also be used to fix a wind barrier to the periphery surface of the module element. As an alternative to the groove in the periphery surface of the structural frame, the vapour barrier (and possibly the wind barrier) may be adhered to the periphery surface of the structural frame by means of an adhesive means. In one embodiment, the adhesive means comprises a diffusion-tight sealing strip, at least one of the faces of the sealing strip including an adhesive.

The module system preferably includes a framework of the kind explained in connection with the first aspect of the invention.

In one embodiment, each of the at least two module elements of the module system may be provided with said framework.

The framework may, independently of whether it is installed in the module system after the module elements have been interconnected into a complete wall construction or a portion of a wall construction or whether each of the module elements are made with a framework, be provided with an insulation means to produce at least a portion of the desired U-value of the construction.

To be able to produce a module element as complete as possible, it is an advantage if the module element is provided with a watertight, but diffusion-open, wind barrier. A person skilled in the art will know that the purpose of such a wind barrier is to provide a barrier for preventing, to the greatest possible extent, air from entering the insulation means and thereby reducing the insulating properties of the insulation means, while, at the same time, any humid air in the insulation will be allowed to escape through the wind barrier. Another important purpose of the wind barrier is to prevent water, for example rain water, from passing the wind barrier and thus wet the insulation before an outer cladding has been applied to a wall construction, for example.

An insulation means which is installed in the framework of the module element according to the invention, may be exposed to an outer environment on the external side of the module element, but also on the side faces of the module element. To also protect the insulation of the module element from water before at least two module elements have been put together for the formation of a portion of a wall construction, it is an advantage if the wind barrier also surrounds the insulation at the side faces of the module element. According to the invention, each of the module elements may be provided with a wind barrier which is installed against the framework and the surfaces of the insulation means that are exposed to an outer environment when the module element is made. A marginal area of the wind barrier may be installed against the periphery surface of the structural frame. It is further an advantage if a marginal area of the wind barrier is fixed to the periphery surface of the structural frame. Such an attachment of the marginal area of the wind barrier may be provided by means of nails or a suitable adhesive. However, such an attachment of the vapour barrier to the structural frame of the module element is encumbered with several of the drawbacks that are discussed above in connection with the attachment of the vapour barrier to the structural frame of the module element.

To ensure as complete a surrounding of the insulation means as possible, it is an advantage if the wind barrier is made in one piece. In one embodiment, the wind-barrier is made as a "sack" or "bag" sewn into shape, adapted for being slid surroundingly around the framework and the insulation means. Such a sack-shaped wind barrier can be slid in from an external side of the module element and over a portion of the periphery surface of the structural frame.

The inventor has surprisingly found that the wind barrier may be attached to the structural frame in a manner corresponding to that of the vapour barrier, namely with the use of a groove and a complementarily adapted sealing strip. Thus, the periphery surface of the structural frame of the module element may be provided with a groove arranged to receive the marginal area of the wind barrier and a complementarily adapted sealing strip adapted for wedging the wind barrier to the groove.

In one embodiment, the marginal area of the wind barrier may be placed in a separate groove and be fixed in this by means of a complementarily adapted sealing strip. A solution like that will require the periphery surfaces of the structural frame to be provided with two grooves, one for the vapour barrier and one for the wind barrier. In a solution like that, a sealing strip configured with two "groove portions" connected by a spacer may be used, or two separate sealing strips may be used. An advantage of using two separate grooves, and especially two separate sealing strips, is that the vapour barrier and the wind barrier can be fixed to the structural frame independently of each other. However, a solution like that, with two separate grooves, may be more laborious, especially if the grooves will have to be milled in two separate operations.

In a prototype of the module element, the marginal area of the wind barrier and the marginal area of the vapour barrier are placed in a common groove and fixed by means of one sealing strip. A solution like that turns out to work excellently. In one embodiment, the vapour barrier and the wind barrier may thus be wedged to one common groove. From the above explanation it will be understood that the framework and the insulation will be protected from water during storage, transport and installation.

The module elements may be formed in such a way that frameworks of two module elements that are placed side by side may be brought to abut against each other. In those cases in which the module elements are provided with insulation means, and especially if the insulation means is protected by a wind barrier before the module elements are fitted together, it may be an advantage if side portions of two adjacent frameworks are provided with receiving means for receiving a complementarily adapted engagement means, so that two adjacent frameworks can be fixed to each other.

In an alternative embodiment, two adjacent sides of two frameworks may be provided with complementarily adapted engagement means which are arranged to mutually engage and produce a locking engagement when the module elements are being installed. Such complementarily adapted engagement means may, for example, be of the kind that is known from the furniture industry for use in connecting elements that form part of a modular sofa, that is to say engagement means of the pin-and-slot type.

In an alternative embodiment, some of the features of the module system described above may be used when manufacturing a module system comprising just one module element. Such a "one-module" system will especially be relevant if the wall construction is of such a size that it will be allowed to be transported on a public road from a place of manufacture to a building site.

According to a third aspect of the present invention there is provided a method for manufacturing a portion of a wall construction for a building, the method comprising the steps of:

- manufacturing a load-bearing wall construction from wood, the wall construction having an external or cold side and an internal or warm side; and

- installing a vapour-barrier on the external side of the load-bearing wall construction.

The load-bearing wall construction may typically be a structural frame of the kind that is mentioned above in connection with the first and second aspects of the invention.

The method may further comprise:

- installing a framework projectingly on the external side of the wall construction, the framework including a plurality of frames, the frames being spaced apart;

- installing an insulation means in and between the frames of the framework; and - installing a wind barrier against at least a portion of the framework.

In one embodiment, the wind barrier is installed only against the side of the framework that faces away from the load-bearing wall construction, against the outward- facing side of the wall construction, then. In another embodiment, the wind barrier is also installed at least over the upper edge of the framework and terminated against a portion of the load-bearing wall construction, so that the insulation means is at least partially surrounded by the wind barrier.

According to the third aspect of the invention, the load-bearing wall construction may be made in situ or as a prefabricated module element. Alternatively, the load-bearing wall construction may be made as a module system comprising at least two module elements arranged to be fixed to each other to provide a portion of the wall construction. In such an alternative method, it may further include installing a framework pro- jectingly on an external side of each of the module elements, the framework comprising a plurality of frames, the frames being spaced apart. The frames may be made of wood .

The method may further comprise installing an insulation means in and between the frames of the framework, so that the space defined by the framework is substantially filled with the insulation means. After the insulation means has been installed in and between the frames of the framework, a wind barrier may be installed against a portion of the framework. In one embodiment, the wind barrier is installed against the side of the framework that faces away from the load-bearing wall construction of the module element. To ensure an overlap of the boundary portion between two adjacent module elements, it is an advantage if the wind barrier in such an embodiment has an extent, at two of its side portions, that is larger than the extent of the module element. In one embodiment, the wind barrier is installed only after the at least two module elements have been connected to each other side by side or at least partially over each other.

As discussed above in connection with the second aspect of the invention, it is an advantage if the wind barrier is installed against the framework and the surfaces of the insulation means that are exposed to an outer environment when the module element is being made. It is further an advantage if a marginal area of the vapour barrier and a marginal area of the wind barrier are installed in a groove arranged in a periphery surface of the structural frame, and to wedge said marginal areas to the groove by means of a sealing strip which is complementarily adapted to the groove. In one embodiment each of the marginal area of the vapour barrier and the marginal area of the wind barrier is wedged to a separate groove in the periphery surface in the structural frame. In an alternative embodiment, each of said marginal areas may be wedged to one common groove in the periphery surface of the structural frame.

As an alternative to the groove in the periphery surface of the structural frame, at least one of the vapour barrier and the wind barrier may be adhered to the periphery surface of the structural frame by means of an adhesive means. In one embodiment, the adhesive means comprises a diffusion-tight sealing strip, at least one of the faces of the sealing strip including an adhesive. The at least one side of the sealing strip that includes the adhesive is the side fixing the vapour barrier and/or the wind barrier to the periphery of the structural frame.

To ensure a stable connection between two adjacent frameworks, the method may further include anchoring a portion of the framework of a first module element to a portion of the framework of an adjacent second module element. Such an anchoring may be provided before or after the wind barrier has been installed on the module elements, according to whether the wind barrier is installed after the module elements have been connected to each other or before the module elements have been connected to each other.

The method may further include installing a furring against the wind barrier. The purpose of the furring is to provide an air gap between the wind barrier and an external cladding. The furring is typically laths that are fixed to an outer portion of the framework. The wind barrier will thus be clamped between the furring and said outer portion of the framework. The external cladding is preferably installed after the at least two module elements have been connected to each other, but it is also conceivable, for example in those cases in which the cladding consists of vertical cladding boards, that at least a portion of the surface of the module element that, in a position of application, is exposed to an outer environment is provided with the external cladding.

According to a fourth aspect of the present invention there is provided a framework for housing an insulation means on an outside of a load-bearing wall construction, the framework comprising an inner frame element for attachment to the load-bearing wall construction, an outer frame element for supporting an external cladding, and a spacer for connecting the outer frame element to the inner frame element, the spacer, in a position of use, having a vertical section which exhibits a height that is larger than the width of the spacer. By width is meant here, as earlier, the extent parallel to the horizontal extent of the wall construction. Thus, the spacer may be a plate-shaped element. The spacer may have a design of the kind discussed in connection with the first aspect of the invention.

In what follows, examples of preferred embodiments are described, which are visualized in the accompanying drawings, in which :

Figure 1 shows a view in perspective of a portion of a wall construction seen from an outside or a cold side, the wall construction comprising a structural frame with an outside which is provided with a vapour barrier, a framework with insulation, a wind barrier and external cladding;

Figure 2a shows a view in perspective of a structural frame formed as a module element;

Figure 2b shows, on a larger scale, a portion of the structural frame shown in figure 2a, seen from a side;

Figure 3a shows a view in perspective of a first embodiment of a framework arranged to be installed against and fixed to the structural frame shown in figure 2a;

Figure 3b shows, on a larger scale, a second embodiment of a framework after it has been fixed to the structural frame shown in figure 2a;

Figure 4a shows a view in perspective of a first embodiment of a prefabricated module element seen from an outside;

Figure 4b shows a view in perspective of a second embodiment of a prefabricated module element;

Figure 5a shows the module element of figure 4a seen from an inside; and Figure 5b shows the module element of figure 4b seen from an inside.

In the description, positional indications, such as "upper", "lower", "right" and "left", refer to the positions that are shown in the figures.

Like or corresponding elements are indicated, to a great degree, by the same reference numerals in the figures.

For illustrative reasons, the relative proportions of individual elements may be somewhat distorted. In some of the figures, some of the elements shown are not indicated by reference numerals, and some elements may have been left out in some figures for the sake of clarity.

In the figures, the reference numeral 1 indicates a wall construction for a building, the wall construction 1 including a structural frame 3. The structural frame 3 includes vertical studs 5 which are fixed, at their end portions, to plates 7 (see for example figure 2a) which, in the exemplary embodiments, are shown as horizontal beams of the same dimension as the studs 5. It should be underlined that one or both of the plates 7 may be non-perpendicularly arranged to the studs 5, and that the plates 7 may have other dimensions than the studs 5.

Figure 1 shows a view in perspective of a portion of a wall construction 1 seen from an external or "cold" side. The wall construction 1 includes a structural frame 3, a framework 20 and external cladding 40.

A vapour barrier 9 is clamped between the external side of the structural frame 3 and the framework 20 by the framework 20 being fixed to the structural frame 3 by means of mechanical fastening means of a kind known per se. The framework 20 includes a plurality of frames 22 spaced apart along the longitudinal direction of the wall construction 1. The frames 22 are typically made of wood, but it is also conceivable that at least some of elements of the frames 22 may be made from a synthetic material. The vapour barrier 9 shown in figure 1 is placed against the structural frame 3 after this has been completed, but before the frames 22 are fixed to the structural frame 3.

The primary purpose of the framework 20 is to house an insulation means 30, so that the insulation means 30 is installed on the outside of the vapour barrier 9 and thereby also on the external or cold side of the structural frame 3. As will be explained below, an insulation means may, in addition, be installed in spaces defined between the studs 5 and plates 7 of the structural frame 3.

Figure 1 further shows a diffusion-open wind barrier 35 which is fixed to the framework 20, for example by means of nails. For the sake of clarity, only an upper, left- hand portion of the wind barrier 35 is shown in hatching. The purpose of the wind barrier 35 is to provide a barrier to prevent, to the greatest possible degree, air from entering the insulation means 30, while, at the same time, any moisture in the insulation means 30 is allowed to flow out through the wind barrier 35. The wind barrier 35 is thus diffusion-open. An outer cladding 40, shown here as upright cladding boards, is installed by means of furring laths 42 and supporting laths 44, installed on the outside of the wind barrier 35 and fixed to the framework 20.

For illustrative reasons, only portions of the insulation means 30, wind barrier 35 and outer cladding 40 of the wall construction 1 are shown.

In figure 1, a foundation F supporting the wall construction 1, and floor joists B that are fixed to and project at right angles from the studs 5 of the structural frame 3 are shown as well. It will thereby be understood that, in the embodiment shown, the structural frame 3 of the wall construction 1 is a load-transmitting one, that is to say a so-called bearing wall. By the very fact of the vapour barrier 9 being installed against the external side of the structural frame 3, the vapour barrier 9 is carried uninterruptedly past the floor joists B. When the vapour barrier is installed on the internal or warm side of the structural frame the way it is done according to recognized prior-art teaching, the joists B will have to be extended through the vapour barrier and consequently perforate this.

Figure 2a shows a view in perspective of a structural frame 3 designed for providing a load-transmitting element in a module element 10 forming part of a module system. The structural frame 3 includes vertical studs 5 (three shown) which are fixed, at their end portions, to plates 7. In the embodiment shown, the plates are of the same dimension as the studs 5. However, it will be understood that the plates 7 and the studs 5 may be of different dimensions, as will be well known to a person skilled in the art. The structural frame 3 shown in figure 2a is, in principle, identical to the structural frame 3 in the wall construction 1 built in situ, shown in figure 1, but built as a module element 10, then.

When a wall construction made by means of a module system according to the present invention is produced, at least two module elements 10 are placed side by side or over each other. When two module elements are placed over each other, they will typically be placed laterally offset relative to each other. Two adjacent portions of the module elements 10 (only one module element shown in the exemplary embodiments) are fixed to each other by means of one of or a combination of a mechanical fastening means, such as a plurality of bolts, and an adhesive. In the embodiment shown in figure 2a, the structural frame 3 is provided with a plurality of bolt holes 12 arranged in a spaced-apart manner around the periphery of the structural frame.

According to the present invention, the external side of the structural frame 3 is provided with a vapour barrier 9 which, in figure 2a, is illustrated with areas of inclined hatching. A challenge with a wall construction that has been made by means of mod- ule elements 10 is to prevent, to the greatest possible degree, leakage between the vapour barrier and the structural frame 3. A possible way of achieving this is fixing the vapour barrier 9 to the external surface of the structural frame 3 by means of a suitable adhesive. By the external surface is meant, in this connection, the surface of the structural frame 3 that is arranged to receive a framework 20 as will be explained below. A drawback of said possible way is that the interface between two adjacent module elements 10 (only one shown in the figures) may be a potential leakage portion if the interface does not have a curable sealing means applied to it. Applying a curable sealing means, such as a silicone- or acrylic-based sealing means, around a periphery of the module element 10 is time-consuming and may be messy.

To ensure a wedging of the vapour barrier 9 to the structural frame 3, the periphery surfaces of the structural frame 3 are provided with a groove 14 as is shown best in figure 2b. The groove extends continuously in the periphery surfaces of the plates 7 and outermost studs 5.

The groove 14 is adapted for receiving a marginal portion or marginal area of the vapour barrier 9. The vapour barrier 9 is wedged to the groove 14 by means of a sealing strip 16 which is complementarily adapted to the groove 14 so that a tight fit is achieved. The sealing strip 16 is shown in figures 3b-5b.

The sealing strip 16 is preferably made from a diffusion-tight elastic material, such as, but not limited to, a rubber-based material or a synthetic material. The sealing strip 16 is formed in such a way that, in the position of use, it projects slightly, for example by 1-5 mm, beyond the periphery surfaces of the structural frame 3. Thereby a sealing of the interface between two adjacent module elements 10, possibly between a module element 10 and a foundation F (see figure 1) may be achieved .

A vapour barrier 9 which is fixed to a groove 14 in the structural frame 3 of a module element 10 by means of the sealing strip 16 is shown in figure 3b.

Reference is now made to figures 3a and 3b which show two different embodiments of a framework 20 according to the invention, the framework 20 being made up of several spaced-apart frames 22 (three shown). Figure 3b shows only an upper portion of the framework 20 that is fixed to a studwork 3.

Each of the frames 20 includes a first or inner lath 24, a second or outer lath 26 which is installed at a distance from the inner lath 24 by means of a spacer 28. The outer laths 26 of the frames 22 are connected at the top and bottom to a frame plate 27. It should be mentioned in this connection that the frames 22 shown in figure 1 are pro- vided with a corresponding frame plate, not shown however.

As shown, in the position of use, the spacer 28 has a vertical section exhibiting a height that is larger than the width or thickness of the spacer. Thus, the spacer 28 may be formed as a plate-shaped spacer 28 as shown in the figures. The purpose of such a design is twofold. Firstly, a plate-shaped spacer 28 may exhibit relatively good load-transmission properties for vertical forces between the second lath 26 and the first lath 24. Secondly, the cross-sectional area of the spacer 28 that is exposed to the cold side of the wall construction 1 or module element 10 will be small in relation to the load-transmission property of the spacer 28. Thereby a cold bridge, which the spacer 28 will necessarily represent, will be as small as possible.

As mentioned above, the purpose of the framework 20 is to provide a space for housing an insulation means 30 as shown in figures 1, 5a and 5b. The insulation means 30 may typically be mineral wool made from glass or stone.

As mentioned initially, such an insulation means has a "minimum bend radius". To avoid, or at least reduce, the possibility of leakage channels forming between the spacers 28 and the insulation means 30 that, in a position of application, has been brought to rest against the spacers 28, the spacers 28 are provided with a first side face which has a length that is different from the length of a second side face. By the term "length" is meant the peripheral length of the spacer 28 measured from top to bottom. In figures 3a and 3b, the first side face, resting against the laths 24, 26 of the frame 22, is straight, whereas the second side face includes an upper sloping portion 29, a lower sloping portion 29' and a plane surface 29" extending between said sloping portions 29, 29'. Thus, the second side face has a larger length than the length of the first side face which, in the position of application, is resting against and is fixed to the laths 24, 26. The transitions between said sloping portions 29, 29' and the intermediate, plane surface 29" are preferably rounded.

To be able to exploit the advantages that prefabrication of module elements entails, it is an advantage if the module element 10 is manufactured as completely as possible. In practice, this is to say a module element 10 with a structural frame 3, vapour barrier 9, framework 20, insulation 30 and a wind barrier 35. Such a "complete" module element 10 is shown in figures 4a and 4b. On account of clarity of the figures, the insulation means 30 is not shown in figures 4a and 4b.

By the very fact of there being access in the structural frame 3 for connecting two adjacent module elements 10, a fixed connection between the structural frames 3 of the module elements may be provided relatively easily. However, it is an advantage if an outer lath 26 and/or a frame plate 27 of the framework 20 of a first module element 10 is connected to an outer lath 26 and/or a frame plate 27 of the framework 20 of a second (not shown) module element. Such a connection is provided, according to the invention, by means of two different methods which still have similarities.

Both methods are based on providing at least the outer lath 26 and/or a frame plate 27 of the framework 20 of each of the module elements 10 that are to be fixed to each other with a receiving means.

In figure 4a, several receiving means 50a (sixteen shown - four on each side face) are spaced apart around the periphery of the framework 20. In the embodiment shown, the receiving means 50a consist of profiles with a C-shaped cross section. The C- shaped profiles 50a are made from metal or a suitable plastic material and fixed by means of screws, for example, to recesses 27a (shown best in figure 3a) arranged in the outer laths 26 and frame plates 27. The opening of the C's of the profiles 50a face away from the outer laths 26 or frame plates 27 to which the the profiles are fixed. After two module elements 10 have been placed against each other, an engagement means (not shown) complementarily adapted to two receiving means 50a positioned adjacent to each other is inserted into the receiving means 50a. Said engagement means will, for example, have an H-shaped profile which is wedged simultaneously into two adjacent receiving means 50a. The engagement means may, for example, be made from a wooden material or, preferably, a suitable plastic material, but other materials of suitable strengths are also conceivable.

Figure 4b shows an alternative embodiment of the receiving means 50a shown in figure 4a. Figure 4b shows a receiving means 50b in the form or rails with C-shaped cross sections installed around the periphery of the framework 20. The C-shaped rails 50b are made of metal or a suitable plastic material and fixed, for example by means of screws, to a shoulder 27b (se figure 3b) arranged in the outer laths 26 and the frame plates 27. The longitudinal axes of the rails 50b thus extend parallel to the longitudinal axes of the laths 26 or the frame plates 27. The openings of the C's of the rails 50b face away from the outer laths 26 or the frame plates 27 to which the rails are fixed. After two module elements 10 have been placed against each other, an elongated engagement means (not shown), which is complementarily adapted to two receiving means 50b positioned adjacent to each other, is inserted into the receiving means 50b. Said engagement means will have a profile arranged to be wedged simultaneously into two adjacent receiving means 50b and provide an interconnection be- tween the two. The engagement means is typically made from a suitable plastic material, but other materials of suitable strengths are also conceivable. An H-shaped rail of aluminium is an example of such other material. Such a rail 50b may consist of several individual elements, be divided, that is.

In the embodiments shown in figures 4a and 4b, the wind barrier 35 extends beyond the lower frame plate 27 and beyond the left-hand lath 26 of the module element 10. The wind barrier 35 is indicated by grid hatching at two of the corner portions of the module element 10, but it will be understood that the wind barrier 35 extends over or covers the entire external side of the module element 10. By the very fact of the wind barrier 35 extending beyond the module element 10, it may provide an overlap to a module element 10 that is installed below or to the left of the module elements 10 shown in figures 4a and 4b. However, it will be understood that said overlap is, strictly speaking, not necessary. This is because the wind barrier 35 in the embodiment shown is formed as a "bag" or "sack" which has been pulled over the framework 20 (and the insulation, not shown, in the framework 20). The wind barrier 35 has been slid in from the external side of the module element 10 and over a portion of the structural frame 3 of the module element 10. This is illustrated in figure 4a with a hatched portion (indicating a portion of the wind barrier 35) at the left-hand top of the side portion of the module element 10. A corresponding solution is illustrated on the right in the side portion of the module element 10 shown in figure 4b, and in figures 5a and 5b.

The part of the wind barrier 35 that is shown as projecting beyond the external side of the module element may typically be made of separate pieces of wind barrier sewn to said bag.

Figures 5a and 5b show the module elements 10 of 4a and 4b, respectively, seen from an internal or "warm" side. The space that is defined between the vapour barrier 9 and the structural frame 3 may be filled at least partially with an insulation means, not shown. Such an insulation means may both increase the temperature-insulating properties of the module element 10, and the sound-insulating properties of the module element 10. Particularly effective is such an insulation in reducing a resonance in the module element 10 after an internal cladding (not shown) has been fixed to the structural frame 3.

Even if it does not appear clearly from figures 4a and 5a, it will be understood that the wind barrier 35 is installed in the recesses 27a before the receiving means 50a are installed in the recesses 27a. Figures 4b and 5b illustrate that the wind barrier 35 is installed in the module element 10 before the receiving means 50b (the C-shaped rails) is installed on the framework 20.

In the embodiments shown in figures 4a to 5b, the marginal area of the wind barrier 35 is placed in the same groove 14 as the marginal area of the vapour barrier 9, and wedged to the groove by means of the sealing strip 16. Thereby a complete seal is achieved against the structural frame 3 of the module element 10.

It is also conceivable that a groove 14 of the kind that is described in connection with figures 2a-2b, 3b-5b is used at least in a portion of a periphery surface of a wall of the kind that is shown in figure 1, built in situ.

The wall construction 1 may be prefabricated as a module element, especially if the extent of the wall construction is of such a size that will allow it to be transported on a public road.

With this, it will be understood that the present invention solves known problems related to necessary and/or undesired perforations of the vapour barrier 9, as there will be easy access to the construction frame 3 for pipes and cables to be extended even after the vapour barrier has been installed against the structural frame 3. With the present invention, so-called boxing, which will reduce an available area of a room defined by the wall construction 1 according to the present invention, will not be necessary either.

It should be noted that all the above-mentioned embodiments illustrate the invention, but do not limit it, and persons skilled in the art may construct many alternative embodiments without departing from the scope of the attached claims.

The use of the verb "to comprise" and its different forms does not exclude the presence of elements or steps that are not mentioned in the claims. The indefinite article "a" or "an" before an element does not exclude the presence of several such elements.

The fact that some features are indicated in mutually different dependent claims does not indicate that a combination of these features cannot be used with advantage.