EP3075913B1

EP3075913B1 - A method for reducing moisture build-up in a cavity of a cavity wall and a foundation wedge

Info

Publication number: EP3075913B1
Application number: EP15194290.1A
Authority: EP
Inventors: Bjarne LAURSEN
Original assignee: Prodatek AS
Current assignee: Prodak AS
Priority date: 2014-11-14
Filing date: 2015-11-12
Publication date: 2018-10-10
Anticipated expiration: 2035-11-12
Also published as: EP3075913A1; PL3075913T3

Description

Field of the invention

The present invention relates a method for reducing moisture build-up in a cavity of a cavity wall of a building. The invention also relates to a foundation wedge to be placed in the cavity between an outer wall and an inner wall.
The invention further relates to a system for preventing encroachment of moisture into areas where foundations and walls in a building meet.
Finally, the invention relates to a building having one or more walls comprising such foundation wedges and/or such a system.

Background of the invention

A building is normally erected by constructing an insulated foundation and subsequently placing external and inner walls and placing the roof structure of the building so that it is carried by at least the external walls.
The external walls normally comprise an outer wall and an inner wall. The outer wall is the outside of the building and constitutes the building envelope of the building, and the inner wall is placed against the inside of the building. Between the outer wall and the inner wall is a cavity which can be filled with insulation material. The expressions outer wall and inner wall should not be taken to mean that these are necessarily masonry walls, as the front and inner walls can also be manufactured from the traditional materials used for inner and outer walls in buildings, such as wooden cladding, plates based on wooden material, e.g. plywood, so-called OSD boards, woodchip boards, MDF boards and similar boards, gas concrete, concrete, bricks, plasterboards etc.
The outer wall and/or the inner wall may be load-bearing for floor decks and/or roof structure, or the external walls may comprise a load-bearing framework of posts made from concrete, reinforced concrete, wood, metal, including steel or light-alloy metal such as aluminium or similar. The load-bearing framework will be cladded by a facade material of a generally known type, constituting the building envelope of the external walls and comprising an inner wall, e.g. in the form of a plasterboard cladding or similar materials which are normally used for inner wall cladding in a building.
In such structures, a risk may occur of condensate forming in the cavity between the inner wall and the outer wall. In addition, there is a risk that any intruding water may run into the cavity between the outer wall and the inner wall. This water will typically collect in the bottom of the cavity between the inner wall and the outer wall and may spill out over the foundation at outer wall, but there is also a large risk that the moisture penetrates the building in the area at the joint between the inner wall and the foundation. This leads to moisture arising in the area, which may result in growth of mildew and/or moulds, which are unwanted in all types of buildings, as they may pose a health risk for the people residing in the building.
Some solutions to those problems have been proposed in the documents US2002/0115367A1 and GB2450798A .

Object of the invention

An object of the invention is to prevent intruding water, condensate and other moisture which collects at the bottom of the cavity between the outer wall and the inner wall in a cavity wall, particularly an external wall, from penetrating into a building in the area where the wall and the foundation meet.
It is also the object of the invention to reduce the risk of mould, rot and similar in a building in the area where a wall, particularly an external wall, and a foundation meet.

Description of the invention

The invention relates to a method for reducing moisture build-up in a cavity of a cavity wall of a building. The method comprises the steps of claim 1.
Arranging the water impermeable sheet so that it extends all the way from the inner face of the inner wall and out to the outer side of the foundation and so that it at the same time inclines downwards in the same (outwards) direction is advantageous in that it hereby is ensured that moisture - e.g. condensed water forming on the inside of the outer wall - building up at the foundation in the cavity is guided efficiently out of the building. Furthermore, building the outer wall on top of the water impermeable sheet - so that the water impermeable sheet extends all the way beneath the outer wall - is advantageous in that it ensure more efficient drainage of fluid from inside the cavity and out under the outer wall.
The water impermeable sheet could be formed by any suitable flexible sheet or foil material such as any kind of Polyethylene (PE) foil, rubber, synthetic rubber, thermoplastic, asphalt material, bitumen, modified bitumen or other or any combination thereof.
In an aspect of the invention, the method comprises arranging a wedge-shaped element between the foundation and the water impermeable sheet in the cavity.
Placing a wedge-shaped element under the water impermeable sheet is advantageous in that it helps maintaining the inclined shape of the water impermeable sheet.
In an aspect of the invention, the wedge-shaped element is pre-attached to the water impermeable sheet before arranging the water impermeable sheet in the cavity.
Connecting the water impermeable sheet to wedge-shaped element - e.g. by means of adhesive - before arranging it on the foundation is advantageous in that it simplifies installation and preceding logistic.
In an aspect of the invention, the wedge-shaped element is formed from a thermal insulating material.
Forming the wedge-shaped element from a thermal insulating material is advantageous in that the risk of the wedge-shaped element acting as a thermal bridge between the inner and outer wall is hereby reduced.
It should be noted that by the term "thermal insulation material" is to be understood any material capable of significantly lowering the thermal conductivity in the wedge area i.e. typically between the outer wall and the inner wall. Such thermal insulation materials include any kind of material having a low thermal conductivity i.e. typically below 0.5 watts per meter kelvin (W·m-1·K-1) such as mineral wool or foam, polymer-based insulation materials - such as expanded or foamed polystyrene (PS), polyurethane (PU, PUR), polyisocyanurate (PIR), polyethylene (PE), polypropylene (PP) - ceramic insulation tiles, glass foam or other and/or any combinations hereof.
In an aspect of the invention, the water impermeable sheet is arranged in an angle A of between 1° and 80°, preferably between 2° and 60° and most preferred between 3° and 35° in relation to a plane perpendicular to the inner face of the inner wall.
If the inclination angle is too steep the water impermeable sheet becomes correspondingly long and thus more expensive. If the inclination angle is too flat the water impermeable sheet will not be as efficient at draining water away from the cavity. Thus, the present angle ranges presents an advantageous relationship between cost and efficiency.
In an aspect of the invention, the water impermeable sheet is connected to the inner face of the inner wall.
Connecting the water impermeable sheet to the inner face of the inner wall is advantageous in that it ensures a more uniform and precise installation.
In an aspect of the invention, the water impermeable sheet is arranged to extend along a part of the inner face of the inner wall in a direction away from the foundation.
Arranging the water impermeable sheet so that it abuts the inner face of the inner wall over a certain distance is advantageous in that this contact zone enables secure fixation and reduces the risk of ingress of water to the underside of the water impermeable sheet.
In an aspect of the invention, joint sealant and/or adhesive is arranged between the water impermeable sheet and the inner face of the inner wall.
Providing joint sealant and/or adhesive between the water impermeable sheet and the inner face of the inner wall is advantageous in that it ensures good fixation and reduces the risk of ingress of water to the underside of the water impermeable sheet.
In an aspect of the invention, the method further comprises the step of covering posts, beams, pipes or other elements extending from the foundation in the cavity and into the cavity with a covering profile.
Covering these elements in a covering profile is advantageous in that the risk of these elements acting as a thermal bridge between the inner and outer wall is hereby reduced. Furthermore the risk of water condensing on these elements is reduced.
In an aspect of the invention, the covering profile comprises at least two or preferably at least three side pieces, wherein the side pieces are connected by an integral hinge.
Connecting the side pieces of the covering profile by integral hinges is advantageous in that it reduces production costs and ensures simple logistics. And arranging hinges between the side pieces is advantageous in that it enables simple and precise mounting on the element.
In this context the term "integral hinge" should be understood as an area at which the profile has a tendency to bend. I.e. an internal hinge not a separate part from the profile but is formed as an integrated part of the profile - e.g. by forming longitudinal bending zones along which the profile will be able to bend back and forth (as a hinge) when subject to a force.
In an aspect of the invention, the covering profile is made from a thermal insulating material.
Making the covering profile comprise a thermal insulating material is advantageous in that the risk of these elements acting as a thermal bridge between the inner and outer wall is hereby further reduced. Furthermore the risk of water condensing on these elements is further reduced.
In an aspect of the invention, the method further comprises the step of covering a transition zone between the water impermeable sheet and posts, beams, pipes or other elements extending from the foundation in the cavity and into the cavity with collar means.
Forming collar means in the transition zone is advantageous in that it reduces the risk of ingress of water to the underside of the water impermeable sheet.
In this context the term "collar means" should be understood as an any kind of flashing, covering, bandage or other form of collar suited for covering a transition zone between a water impermeable sheet and posts, beams, pipes or other elements.
In an aspect of the invention, joint sealant and/or adhesive is arranged between the collar means and the water impermeable sheet and/or between the collar means and the posts, beams, pipes or other elements.
Arranging joint sealant and/or adhesive between the collar means and the water impermeable sheet and/or between the collar means and the posts, beams, pipes or other elements further reduces the risk of ingress of water to the underside of the water impermeable sheet.
In an aspect of the invention, the collar means are made from the same material as the water impermeable sheet.
Forming the collar means and the water impermeable sheet from substantially the same material is advantageous in that it simplifies installation and logistic and it reduces cost.
The invention further relates to a foundation wedge, comprising a wedge-shaped element having an underside, a side face and an oblique upper side, and wherein the wedge-shaped element is manufactured from an insulation material, the wedge-shaped element being covered by a water impermeable sheet that extends beyond at least two of the parallel edges of the upper side.
An object of the invention is further achieved using a system to prevent encroachment of moisture into areas where foundations and walls in a building meet. The building comprises a foundation and walls located on the foundation, the walls comprising a outer wall and a inner wall placed at a distance from the outer wall. The system comprises the foundation wedge, which is located along the inner wall on the surface of the foundation in the cavity between the outer wall and the inner wall, and the water impermeable sheet of the foundation wedge has been led some distance up against the inner wall and out over the foundation and under the outer wall.
By letting the width of the water impermeable sheet be bigger than the width of the wedge element, it is achieved that the water impermeable sheet can be laid some distance up against the inner wall and over the foundation and under the outer wall. It can thus be avoided to lay the traditionally used strip of water impermeable sheet under the outer wall, as the water impermeable sheet of the foundation wedge can replace this.
Hereby it is also achieved that condensate and intruding water are efficiently conducted away from the area where the inner wall is located on the foundation, as the water is collected on top of the water impermeable sheet and can be conducted out under the outer wall. The oblique upper side of the wedge-shaped element efficiently conducts the water away from the inner wall and towards the outer wall, where it has the possibility of escaping, because the water impermeable sheet extends in under the outer wall. Thereby, the risk of moisture damage is reduced in the area where the inner wall and the foundation meet as well as in the foundation itself. By reducing the risk that the construction materials in this area absorb moisture, the risk of the possibility arising for growth of mildew, moulds and similar in the area of the building is also eliminated or at least reduced significantly.
The foundation wedge is typically placed in the gap after the erection or manufacture of the inner wall, and before the outer wall is erected or manufactured. The foundation wedge can thus be used both in connection with in situ erection of a building, but can also be used in pre-fabricated wall elements manufactured at the factory and transported to the construction site and erected.
The wedge-shaped element is according to the invention fixed on the water impermeable sheet, preferably by glueing, as this makes it easier to handle the foundation wedge and thus also quicker to mount it correctly. It is also possible to use the foundation wedge as two spare parts placed individually when erecting the external wall.
The wedge-shaped element has a rectangular ground plan, wherein the cross-section perpendicularly to the longitudinal direction of the wedge-shaped element is wedge-shaped, the oblique upper side extending from the side wall in the longitudinal direction along the one longitudinal side of the rectangular ground plan to the pointed edge along the other longitudinal side of the rectangular ground plan.
By manufacturing the wedge-shaped element from insulation material, it is furthermore achieved that the risk of any thermal bridges in the area is reduced. Suitable insulation materials are commonly used in construction and are e.g. rock wool, glass wool, polymer-based insulation materials, such as expanded or foamed polystyrene (PS), polyurethane (PU or PUR), polyisocyanurate (PIR), polyethylene (PE), polypropylene (PP) and/or combinations thereof. It is preferred that the insulation material is pressure-resistant, e.g. pressure-resistant rock wool, as the wedge-shaped element is thus dimensionally stable and does not lose its wedge shape during transport, handling and/or mounting.
The water impermeable sheet of the foundation wedge is manufactured from felt board, wall board, foil and/or combinations thereof. Felt board and wall board are commonly known building materials and consist of a fibrous layer, most often made from synthetic fibres, coated with layers of bitumen or a mixture of bitumen and synthetic rubber which normally cover both sides of the fibrous layer. Suitable foils are also known from the construction industry and are e.g. made from polyethylene (PE), low-density polyethylene (LDPE) or rubber-based foils, such as ethylene propylene diene rubber (EPDM), which are also used in the construction industry.
In order to avoid that intruding water or condensate runs in between the water impermeable sheet and the inner wall, a joint or an adhesive is placed between the top edge of the water impermeable sheet and the inner wall. The joint, e.g. mastic sealant, acrylic sealant or silicone sealant, is preferably laid manually between the water impermeable sheet and the inner wall in connection with the mounting of the foundation wedge.
Alternatively, the foundation wedge is manufactured with an adhesive strip along one or more edges of the water impermeable sheet and at least along the side of the edge which is intended to abut the inner wall. Before use, the adhesive strip is preferably covered by a protective strip, which is torn off before the adhesive strip is pressed against the inner wall. By also applying an adhesive strip along the other of the parallel side edges of the water impermeable sheet, it becomes possible to also adhere the water impermeable sheet to the foundation, i.e. under the outer wall, as the second adhesive strip is located on the same side of the water impermeable sheet. Along the ends of the foundation wedge, it is preferred that the adhesive strip at one end is placed on the opposite side of the water impermeable sheet in relation to the above-mentioned adhesive strips. Any further adhesive strip at the other end of the water impermeable sheet of the wedge element is placed on the same side of the water impermeable sheet as the adhesive strips along the longitudinal sides of the water impermeable sheet. This makes it possible to adhere the water impermeable sheets of several foundation wedges together in continuation of each other, so that they constitute an overall surface for the entire length of the wall. Alternatively, a tape roll is used, which is adhered over the joints between the individual pieces of water impermeable sheet, or an adhesive is used, which is applied to one or both layers of water impermeable sheet in an overlap between two water impermeable sheets on to foundation wedges placed in in continuation of each other in the cavity between the front and inner wall.
The system according to the invention preferably comprises a covering profile for covering posts and/or doors placed in the wall.
In one variant, the covering profile comprises a U-profile with perpendicular flanges along one end of the U-profile. The U-profile itself thus covers the post or the frame at the door, and stands on the flange on the foundation. The U-profile is preferably manufactured from plastic, so that no thermal bridge occurs in the wall where the U-profile is mounted. It is possible to cut a triangle out of the U-profile and the corresponding lower flange in the area which abuts the wedge element of the foundation wedge, corresponding to the triangular cross-section of the wedge element, so that the U-profile can be placed around the post after the foundation wedge has been located in the cavity in the wall. For completion, it is advantageous to seal the joint between the water impermeable sheet on the foundation wedge and the U-profile as described above. This also achieves protection against encroachment of moisture in the areas around the posts and/or the doors in the wall and thus also a reduced risk of growth of mildew and moulds in these areas. The covering profile is a substantially U-shaped profile made from hard plastic, such as polyethylene (PE), polypropylene (PP) or polyester/polyethylene terephthalate (PET) and/or combinations thereof, and has a sufficient material thickness to make the U-profile flexible, so that it can easily be mounted around the post while at same time being self-supporting.
In a variant of the covering profile, this comprises at least two or preferably at least three side pieces made from an insulating foam-shaped material, wherein the side pieces are connected by an integral hinge. The covering profile is manufactured from foamed plastic, e.g. PE plastic foam, e.g. by extrusion, and is adapted to the form of the posts as detailed below. A particularly suitable plastic foam is a cross-linked PE plastic foam with closed cells. The plastic foam covering profile adapts easily to the form of the posts, as the material is flexible. There is therefore no need for major precision during the manufacture of the covering profiles. After mounting, the outer surface of the covering profile will preferably have a square or rectangular form, so that it is easy to fix the water impermeable sheet of the foundation wedge to the surface of the covering profile. Thereby, the covering profile, in addition to serving as a substructure for fixing of the water impermeable sheet of the foundation wedge, as described above, can also insulate the post, so that the risk of thermal bridge occurring at the posts is reduced or completely avoided, and any problems arising as a result of condensate issues arising in the cavity between the outer and inner wall are eliminated or at least reduced significantly. This variant of the covering profile can be used to cover vertical post profiles as well as horizontal beam profiles and also other profiles built into a wall in a building.
The invention further relates to a wall, a wall element and/or a building comprising one or more walls with a foundation wedge or a system according to the invention.

Description of the drawings

In the following, the invention will be described with reference to the drawings, wherein

Fig. 1: shows a cross-section through a wall, preferably an external wall, and the foundation in a building,
Fig. 2: shows a foundation wedge according to the invention in an underside view in relation to mounted position,
Fig. 3: shows a covering profile for the system according to the invention,
Fig. 4: shows a system according to the invention, where an alternative covering profile has been used for a post having H-profile,
Fig. 5: shows, in a cross-section view, a principle sketch of mounting of the alternative covering profile around a post having H-profile,
Figs. 6a-6g: show, in a cross-section view, alternative covering profiles for posts etc. having alternative cross-sections, and
Fig. 7: shows a cross-section through a wall, having a foundation wedge according to the invention at the foundation in the building.

Detailed description of the invention

Fig. 1 shows a cross-section through a cavity wall 1, shown here an external wall 1 and a foundation 2.
The external wall 1 has an outer wall 3, which is the outside and the building envelope of the building, an inner wall 4 and a cavity 5 between the outer wall 3 and the inner wall 4. The gap or the cavity 5 in the wall is adapted to become filled with insulation material (not shown).
A foundation wedge 6 according to the invention comprises a wedge-shaped element 7 made from insulation material and a water impermeable sheet 8, see also Fig. 2. The wedge-shaped element 7 has a rectangular ground plan, which can be seen most clearly in Fig. 2, wherein the cross-section perpendicularly to the longitudinal direction of the wedge-shaped element 7 is wedge-shaped, the oblique upper surface 10 of the wedge element extending from a side wall 11 along the one longitudinal side of the rectangular ground plan to the pointed edge 12 of the wedge along the other longitudinal side of the rectangular ground plan. The side wall 11 of the wedge element 7 is perpendicular to the lower face 13.
The foundation wedge 6 is placed on the foundation 2 between the outer wall 3 and the inner wall 4, so that the vertical side face 11 of the wedge element is placed up against the inner wall 4.
The foundation wedge 6 according to the invention can be seen in Fig. 2, which shows the foundation wedge 6 in a bottom view in relation to the mounting position. The foundation wedge 6 comprises an oblong, rectangular wedge element, wherein the inclined upper surface 10 of the wedge element 7 is covered by the water impermeable sheet 8, which is larger than the inclined upper surface 10. The water impermeable sheet 8 is e.g. cut to a size so that it has an edge 14 with a width d along the side edges of the inclined surface 10 of the wedge element 7. Thereby, the water impermeable sheet 8 can cover the foundation 2 in under the outer wall 3 and at the same time extends some distance up against the inner wall 4, see Fig. 1.
A joint 9 is placed along the top edge of the water impermeable sheet 8, where this lays against the inner wall 4, to avoid that condensate and intruding water runs behind the water impermeable sheet. The joint 9 could preferably comprise a sealant and/or an adhesive. Alternatively, the foundation wedge 6 is provided with one or more adhesive strips along the outer edge 14 of the water impermeable sheet 8 as described above.
Intruding water or condensate will run down the water impermeable sheet 8, and because of the oblique upper side 10 of the wedge element 7, the water will be led towards the outer wall 3, as shown by the arrows in Fig. 1, where it can penetrate through the outer wall 3 and thus be led out of the cavity 5 between outer wall 3 and inner wall 4. This avoids moisture problems occurring in the outside area 15 of the inner wall 4 - i.e. on the inside of the building - where the inner wall 4 is placed on the foundation 2. It also reduces the risk of growth of rot or mould occurring in this area 15.
Fig. 3 shows collar means 16 for mounting around posts, pipes, transversal structural element or other elements placed in the cavity 5 in the wall 1. The collar means 16 is in this embodiment shaped as a U-profile 17, wherein the opening 18 in the U-profile is placed around a post in the cavity 5 in the wall 1.
In this embodiment the U-profile rests on the foundation 2 on a first flange 19 while a second flange 20 is placed up against the inner wall 4 to securely seal in the post. An opening 21 may possibly be cut, corresponding to the cross-section in the wedge element 7 in the side wall of the U-profile 17 at the first flange 19, where the foundation wedge 6 abuts the collar means 16. The water impermeable sheet 8 is fixed to the collar means 16 using a joint sealant, adhesive or adhesive strip in the same way as described above. The collar means 16 is preferably made from any suitable flexible sheet or foil material such as any kind of rubber, synthetic rubber, thermoplastic, asphalt material, bitumen, modified bitumen or other or any combination thereof.
In another embodiment the collar means 16 would fully enclose the posts, pipes, transversal structural elements or other elements (or covering profiles as discussed later) at the transition zone with the water impermeable sheet 8, so that the collar means 16 would only abut the elements and the water impermeable sheet 8.
If the collar means 16 preferably is made from a flexible sheet or foil material the collar means 16 can be adapted to fit around any kind of element and ensure a relatively tight seal between these element and the water impermeable sheet 8.
A covering profile 22 for mounting around posts, pipes, transversal structural elements or other elements and/or at doors placed in the wall, is shown in Figs. 4-6. The covering profile 22 is manufactured from foamed plastic, such as expanded or foamed polystyrene (PS), polyurethane (PU, PUR), polyisocyanurate (PIR), polyethylene (PE), polypropylene (PP) and/or combinations hereof, and is adapted to the form of the post. Thereby, the covering profile 22, in addition to acting as a substructure for fixing of the water impermeable sheet 8 of the foundation wedge 6, as described above, it can also insulate the post, so that the risk of a thermal bridge occurring at the posts is reduced or completely avoided. A cross-section of a covering profile 22 for a post 23 having an H-profile is shown in Fig. 5. The covering profile 22 has a first wall 24a and two further walls 24b and 24c, which are fixed to the first wall 24a using an integral hinge 25. The material thickness of the walls 24b and 24c is thinner in the area 27 at the integral hinge and along the outer end 27' of the wall, so that the middle area 28 of the walls 24b and 24c fit into the H-profile 23. The covering profile 22 is mounted around the H-profile by laying the first wall against the outside of one of the outer faces of the H-profile 23 and then tilting the two side walls 24b, 24c into place, as shown with the arrows in in Fig. 5, so that the middle area 28 is pressed in between the arms 29' and 29" of the H-profile.
Similar covering profiles 22c-22g for posts having different profiles are shown in Figs. 6a-6g. Covering profiles are shown here for a differently mounted H-profile (Fig. 6e), U-profiles (Figs. 6c and 6g), T-profiles (Fig. 6d) and I-profiles (Fig. 6f). These covering profiles 22c-22g comprise, as described above, three walls connected by integral hinges 25, which each constitute a corner of the outer face of the mounted covering profile.
Fig. 6a shows an alternative covering profile for posts with circular cross-section (Fig. 6a), e.g. threaded poles, and Fig. 6b shows a similar covering profile 22b for posts with square or rectangular cross-section (Fig. 6b). These covering profiles 22a and 22b have two walls which are connected by an integral hinge 25. The inside of the walls has grooves 30, shown here as semi-circular in Fig. 6a and rectangular in Fig. 6b, or they can be square so as to fit around the relevant post profile. However, other shapes of the grooves 30 are also possible, as the shape of the grooves must merely be adapted to the cross-section of the post profile used.
After mounting, the outer surface of the covering profile 22 will preferably have a square or rectangular shape, so that it is easy to arrange collar means in the transition zone between the covering profile 22 and the water impermeable sheet 8 of the foundation wedge 6.
The covering profile 22 can also be used for covering horizontal beams or other none vertical profiles and elements.
A joint or collar means may also be arranged along the upper end of the covering profile 22 to avoid that intruding water or condensate runs enters the covering profile.
Fig. 7 shows a cross-section through a cavity wall 1, having a post 23 placed in the cavity 5 of the wall 1.
In this embodiment the post 23 is covered by a covering profile 22 that is mounted around a post starting from the foundation 2 and up to the upper end of the post 23. In this embodiment the foundation wedge 6 is fitted to the covering profile 22. The fitting of the foundation wedge 6 can be performed by carving out a hole about the same shape and size of with the covering profile 22. However in another embodiment the foundation wedge 6 could be cut in a straight line and then arranged to merely abut the covering profile 22.
Collar means 16 are fixated on top of the water impermeable sheet 8 such that it creates a tight seal between the covering profile 22 and the water impermeable sheet 8. In this embodiment this seal is formed by an adhesive material, however in another embodiment this seal can be made by means of clamps, needles, soldering, joint sealant or similar.
In another embodiment a bottom part the covering profile 22 is removed such that it abuts the water impermeable sheet 8. In this embodiment the foundation wedge 6 is fitted to the size and shape of the post 23.
The invention has been exemplified above with reference to specific examples of Wedge-shaped elements 7, water impermeable sheets 8, collar means 16 and other. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims.

List

1. Wall
2. Foundation
3. Outer wall
4. Inner wall
5. Cavity
6. Foundation wedge
7. Wedge-shaped element
8. Water impermeable sheet
9. Joint
10. Inclined upper surface
11. Vertical side face
12. Pointed edge
13. Lower face
14. Outer edge
15. Outside area of inner wall
16. Collar means
17. U-profile
18. Opening in the U-profile
19. First flange
20. Second flange
21. Opening
22. Covering profile
23. Post
24a. First wall
24b, 24c. Side wall
25. Integral hinge
26. Inner side of foundation
27. Area at the integral hinge
27'. Outer end 28. Middle area
29', 29". Arm
30. Inner face of inner wall
31. Outer side of foundation
A. Inclination angle of wedge-shaped element
d. Width

Claims

A method for reducing moisture build-up in a cavity (5) of a cavity wall (1) of a building, said method comprising the steps of:
• constructing an inner wall (4) on a foundation (2) of said building substantially along an inner side of said foundation,

• arranging a flexible water impermeable sheet (8) so that it extends from an inner face of said inner wall (30) and across said cavity (5) to an outer side of said foundation (31), and

• constructing an outer wall (3) on said water impermeable sheet (8) along an outer side of said foundation (31) so that said cavity (5) is formed between said inner wall (4) and said outer wall (3),
wherein said water impermeable sheet (8) is at least partly arranged to incline downwards from said inner wall (4) towards said outer wall (3),
wherein said method comprises arranging a wedge-shaped element (7) between said foundation (2) and said water impermeable sheet (8) in said cavity (5), and
wherein said wedge-shaped element (7) is pre-attached to said water impermeable sheet (8) before arranging said water impermeable sheet (8) in said cavity (5).
A method according to claim 1, wherein said wedge-shaped element (7) is formed from a thermal insulating material.
A method according to claim 1 or 2, wherein said water impermeable sheet (8) is arranged in an angle of between 1° and 80°, preferably between 2° and 60° and most preferred between 3° and 35° in relation to a plane perpendicular to said inner face of said inner wall (30).
A method according to any of the preceding claims, wherein said water impermeable sheet (8) is connected to said inner face of said inner wall (30).
A method according to any of the preceding claims, wherein said water impermeable sheet (8) is arranged to extend along a part of said inner face of said inner wall (30) in a direction away from said foundation (2).
A method according to any of the preceding claims, wherein joint (9) sealant and/or adhesive is arranged between said water impermeable sheet (8) and said inner face of said inner wall (30).
A method according to any of the preceding claims, wherein said method further comprises the step of covering posts, beams, pipes or other elements extending from said foundation (2) in said cavity (5) and into said cavity (5) with a covering profile (22).
A method according to claim 7, wherein said covering profile (22) comprises at least two or preferably at least three side pieces (24), wherein said side pieces are connected by an integral hinge (25).
A method according to claim 8, wherein said covering profile (22) is made from a thermal insulating material.
A method according to any of the preceding claims, wherein said method further comprises the step of covering a transition zone between said water impermeable sheet (8) and posts, beams, pipes or other elements extending from said foundation (2) in said cavity (5) and into said cavity (5) with collar means (16).
A method according to claim 10, wherein joint (9) sealant and/or adhesive is arranged between said collar means (16) and said water impermeable sheet (8) and/or between said collar means (16) and said posts, beams, pipes or other elements.
A method according to claim 10 or 11, wherein said collar means (16) are made from the same material as said water impermeable sheet (8).
A foundation wedge (6), comprising a wedge-shaped element (7) having an underside, a side face and an oblique upper side, and wherein the wedge-shaped element (7) is manufactured from an insulation material, the wedge-shaped element (7) being connected to a flexible water impermeable sheet (8) that extends beyond at least two of the parallel edges of the upper side.