Abstract:
A damp protection arrangement for a space confined by floor, ceiling and wall portions in a building and comprising the following components: a damp permeable first layer structure ( 80 ), inside the space comprising at least one wall portion ( 16/80 ) of said portions; a second layer structure ( 60 ), inside the space covering at least the first layer structure ( 60/80 ); a continuous air gap ( 50 ), separated from the space and defined between the first and the second layer structures; an air inlet at a lower level in the space and communicating with the air gap ( 50 ); an air outlet at a higher level in the space and communicating with the air gap; and heating source ( 54 ) inside the air gap ( 50 ) for providing an air flow in the air gap between the inlet and the outlet and capable of dehumidifying layer structures.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a damp protection arrangement for a space confined by floor, roof and wall portions in a building. The invention also relates to a method of protecting such a space from damp. 
       BACKGROUND 
       [0002]    The problems related to damage from damp are serious when, as is common in Nordic countries, the houses are constructed with hollow spaces in floor structures and walls. Mildew damage as well as chemical emissions arise if water enters these hollow spaces. This problem grew when the houses were made tight in the beginning of the seventies. Thereby also the natural ventilation that occurs in floor structures and walls was also removed. 
         [0003]    In Sweden alone the cost for damp damage is equivalent to about a half billion           A smaller part of this cost includes the cost of repairing leakage such as fractured pipes etc. The main part of this cost is in the work in connection with tearing up, drying and reconstructing the spaces, for example bathrooms, that are subjected to water damage. This is in spite of the leak possibly being located at a quite different place than the bathroom. Currently a problem is also that many rather newly installed bathrooms have to be teared up and dried out solely of the reason that the impermeable layers of an upstair neighbor are leaking. 
         [0004]    The insights forming the basis of the invention may be expressed as follows:
       If a water damage were observed on an early stage, large costs would be saved.   If the damp could be dried out without having to tear away walls and floor structures, still more costs would be saved.   If the damp within the walls could be ventilated away in a controllable manner, emissions causing illness would also be ventilated away, and the number of bad houses would decrease.   If the necessary measures resulted in cost savings they would be employed.   If the necessary measures did not use up space, they would also be used.   If the necessary measures were simple, the craftsmen would adopt them.   If the necessary measures can be applied within current regulations, there are no formal obstacles to apply them.       
 
       PRIOR ART 
       [0012]    It is known from SE 9701542-4 C2 to install board elements mounted spaced from walls and floor for the purpose of ventilating a room, so that between the walls and the floor a ventilation space is formed for a through flow of air. This technology is used in order to ventilating away detrimental concentrations of damp and gases, such as radon gas, in a preventive purpose. 
         [0013]    For wet spaces such as bathrooms and the like, it is known from SE 8203579-1 B to ventilate a damp sub floor by an impermeable, damp proof board at a space from the floor, which board extends upwards along and also at a distance from a lower portion of an adjacent wall. 
       DISCLOSURE OF THE INVENTION 
       [0014]    An object of the invention is to further develop the prior art and provide a low-cost, simple and space-saving solution to the problems of damp, particularly but not exclusively in wet spaces. 
         [0015]    In accordance with an aspect of the invention, the damp protection arrangement comprises the following features in combination:
       A damp permeable first layer structure inside the space comprising at least one wall portion of said portions.       
 
         [0017]    Thereby, portions lying behind such as insulation in the building may be defined and be provided a well defined flow-promoting smooth face of an air gap capable of conveying damp mixed up with possibly harmful substances.
       A second layer structure, inside the space covering at least the first layer structure.       
 
         [0019]    Thereby also a smooth face may be defined, i.e. the opposite face of the air gap. The second layer structure may be optionally permeable to damp for being suitable in a wet space, or permeable to damp for being suitable for other types of spaces that run the risk of being subjected to damp damages.
       A continuous air gap, separated from the space defined between the first and the second layer structure.       
 
         [0021]    Thereby an insulated passage is provided for accumulation and exposure of damp, for interaction with an air flow and for transport of resulting damp air in the space.
       An air inlet at a lower level in the space and communicating with the air gap.       
 
         [0023]    Thereby a passage may be provided for transport of dry air to the air gap.
       An air outlet at a higher level in the space and communicating with the air gap.       
 
         [0025]    Thereby a passage may be provided for transport of the damp air out of the space.
       A heating source inside the air gap for providing an air flow in the air gap between the inlet and the outlet and capable of dehumidifying the layer structures.       
 
         [0027]    By the heating source being located inside the air gap, the heating source can directly heat the dry air, so that the dry air will have a high tendency to attract the damp or humidity, possibly mixed up with harmful substances, and bring the resulting humid air into motion upwards to the outlet and out of the building. 
         [0028]    Other features and advantages of the present invention are apparent from the claims and the following detailed description of exemplary embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0029]      FIG. 1  is a diagrammatic sectional cutaway view of a building having a space provided with a damp protection arrangement according to the invention; 
           [0030]      FIG. 2  is a detail view in larger scale of a first encircled area of  FIG. 1 ; 
           [0031]      FIG. 3  is a detail view in larger scale of a second encircled area of  FIG. 1 ; and 
           [0032]      FIG. 4  is a detail view in larger scale of a third encircled area of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0033]    Generally referenced by  10  in  FIG. 1  is a portion of a building having a floor portion  12 , a ceiling portion  14  and wall portion  16  defining a wet space  24 . While the damp protection arrangement in the exemplary embodiment is described in connection with a wet space, and primarily may be applied to wet spaces, the damp protection arrangement according to the invention, as the invention is defined in the claims, may also be applied to other spaces that run the risk of being subjected to damp damages, for example spaces directly below a leaking roof. For the access to the wet space, also shown is a door  26 . 
         [0034]    The floor, ceiling and wall portions  12 ,  14 ,  16  may be of varying construction. While the invention may be applied on pure concrete structures, it is primarily intended for portions, for example infill portions having battens and beams (not shown) defining hollow spaces that in turn may be filled with heat insulating materials  20  and  22  respectively. Such portions are particularly sensitive to damp damages. 
         [0035]    According to the invention, inside the wet space  24  confined by the floor, ceiling and wall portions  12 ,  14 ,  16 , a damp protection arrangement is provided, comprising a damp permeable layer structure  70 ,  80  and a damp impermeable layer structure  40 ,  60  that define a continuous air gap  50  therebetween. It is to be noted that  FIG. 1  shows the damp protecting arrangement only in illustrative purpose, showing excessive thicknesses and spacings between the layer structures. A damp protection arrangement according to the invention needs no more space than a conventional original layer construction in a wet space. In principle only the thin air gap and the thin damp permeable layer  80  are added in the wall portions  16 , while in the floor portion  12  only the air gap is added; in conventional wet space walls often double layers of gypsum wall board is used, were the added gypsum layer is about as thick as the air gap. Doubled gypsum wall board layers are, however, unsuitable together with the present invention, as the resulting doubled paper layers between the boards suck up water and acts as obstructing to the dehumidification. 
         [0036]    While the layer structures in the embodiment shown are indicated as stretching over all floor and wall portions,  12 ,  16 , they may be used to a varying extent in many combinations depending on varying constructions of the floor and wall portions in the particular case. In an extreme case, for example comprising a concrete building structure having only one differing wall portion that is especially sensitive to damp damage, it may be sufficient to use the layers structures  60 ,  80  only at the corresponding wall face in the wet space (not shown). In the normal case, however, the layer structures extend also over the floor portion  12  of the wet space  24  and over all wall portions. Directly to the ceiling portion  14  there should not be any layer structure at all as that structure then would run the risk of keeping damp in the corresponding concrete structure or in the insulating material  20 . In the example shown, a damp permeable ceiling layer  90  needs to be spaced from the ceiling portion  14  to keep the continuous air gap  50  separated or insulated from the damp protected wet space  24 . 
         [0037]    As is more clearly apparent from  FIG. 2 , the damp permeable layer structure  80  adjacent to a wall portion  16 , comprises a damp permeable layer  82 . The outer face of the damp permeable layer  82  serves to form a preferably flat face of the air gap  50  and to keep possible insulations  22  in place in the wall portion  16  lying behind. It is however, within the scope of the appended claims also conceivable that the damp permeable layer structure is composed of the present wall portion only, with or without insulation and without any supplementary layer. The damp permeable layer  82  is however in the embodiment shown preferably a cloth of geotextile or a board of cement; also other materials may however be suitable. 
         [0038]    The layer structures  16  adjacent to the wall portion  16  comprises from the inside and out to the wet space  24  a supporting layer  66 , a damp impermeable layer  64  and a surface layer  62 . The support layer  66 , the inner face of which serves to form the opposite flat face of the air gap  50  and the outer face of which accordingly carries the impermeable layer  64  and the surface layer  62 , is a board of wet room gypsum in the exemplary embodiment but can also consist of other supporting board materials. The impermeable layer  64  is a water tight moisture barrier of a known type applied to the outer surface of the support layer  66 . On the impermeable layer  64  the surface layer is finally applied in a conventional manner, in the exemplary embodiment a layer of tiles together with fastening and joining compounds. 
         [0039]    As is more clearly apparent from  FIG. 3 , the damp permeable layer structure  70  adjoining a floor portion  12 , comprises a damp permeable layer  72 . The top face of the damp permeable layer  72  serves to form a flat face of the air gap  50  and to keep possible insulation  20  in place in the underlying floor portion  12 . In the exemplary embodiment, the damp permeable layer  72  is a conventional—in case of a reconstruction possibly already present—sub floor layer, for example made of floor boards based on wood fibers, but also other materials may be suitable. In order to increase the damp permeability in relatively impermeably sub floor layers, ventilating bores  74  may be drilled by using a suitable bore diameter and distribution over the floor surface, as indicated by 15 lines in  FIG. 3 . The bores  74  may be covered by a vapour permeable but water impermeable cloth  76 . 
         [0040]    The layer structure  40  adjoining the floor portion  12 , in the exemplary embodiment comprises from the inside and out to the wet space  24 , a support layer  48 , a layer  46  providing floor inclination, an impermeable layer  44  and a surface layer  42 . The support layer  48  the inside of which serves the purpose of forming the opposite flat side of the air gap  50  and the outside of which accordingly supports the remaining layers  46 ,  44 ,  42 , in the exemplary embodiment for example a conventional damp resistant floor board of a gypsum type, but may also consist of other supporting board materials. The layer  46  that provides the inclination to the floor is a filling compound  46  of a known type. The impermeable layer  44  is a moisture barrier of a known type applied on the top surface of the layer  46 . On the impermeable layer  44  is finally applied the surface layer  62  in a conventional manner, in the exemplary embodiment a clinker layer together with fastening and joining compound. 
         [0041]    The gap width of the air gap  50  that typically can be about 1 cm, is maintained between adjoining layer structures  40 ,  70  and  60 ,  80  respectively, by spacers  52  such as elongated strips or spars of wood material. Other types of spacers may however also be usable. As is indicated in  FIG. 3  by the broken spacer  52  in the air gap  50 , the spacers at the floor portion  12  may be arranged by interspaces in the longitudinal as well as in the transverse direction in the floor plane in order that the air flow from the air gap  50  at the floor portion  12  may be distributed to mutually perpendicular air gaps  50  at the wall portion  16 . 
         [0042]    To heat the air in the air gap  50  and to increase the air flow that is indicated by filled arrows on the drawing, in the embodiment shown there is provided a heating cable  54  ( 2 ) at a low level inside the portion of air gap  50  that extends along the wall portions  16 . The heating cable  54  is in a suitable manner, for example by cable clamps  56 , attached to the outside of the damp permeable layer  80 , and runs horizontally across the air flow along the entire air gap  50 . As is indicated in  FIG. 1 , the heating cable is connected to the electric network (not shown) of the building  10  through an electric cable  100 . An electronic unit  102  may in a manner known per se be provided with a switch for switching the heating power on and off, and possibly also be provided with equipment capable of controlling the heating power. 
         [0043]    As is further indicated in  FIG. 1 , the damp protection arrangement can also be adapted to monitor the state of the air gap  50  and be brought into function by itself: In the air gap  50  is a sensor  104  adapted to sense the presence of damp or moisture in the air gap  50  and to signal the result through a signal line  106  to the electronic unit  102  so that the unit  102  is capable of turning on and off and/or controlling the heating power in response to the signals from the sensor  104 . 
         [0044]    While the inlet for dry air to the air gap  50  may be arranged in other ways at a low level in the wet space  24 , in the embodiment according to  FIG. 4  an air inlet  30  extends to the air gap  50  in the level of the air gap  50  through a threshold  28  at the door  26  to the wet space  24 . The air inlet  30  can consist of a plurality of transverse openings or an elongated gap or slot in the threshold  28  and have an inlet filter (not shown) preventing inlet of dust or the like. 
         [0045]    In the embodiment shown in  FIG. 1 , the outlet for air from air gap  50  comprises a piece  92  of tubing extending from the inside of the wet space  24  through the ceiling layer  90  to an exhausted passage  96  in the building  10 . The portion of the piece  92  of tubing that is insulated from the wet space  24  by the ceiling layer  90  is provided with perforations  94  through which the air from air gap  50  can be sucked out to the exhausted passage  96  and out of the building  10 . 
         [0046]    Pipes for water and sewer to the wet space  24  are insulated in the passage through the air gap  50  in a suitable manner, for example by sleeves of expanded plastics material (not shown).