Abstract:
A product, and a wall system utilizing such product, adapted to allow drainage of moisture from a wall of a structure. A sheet of corrugated material forms a plurality of ridges and grooves on opposite sides of the sheet of corrugated material. The sheet of corrugated material is relatively inflexible under a force applied generally perpendicular to the sheet. The sheet of corrugated material has a multiplicity of perforations. A sheet of water permeable material is affixed to one side of the sheet of corrugated material. The product is flexible in a direction along the plurality of ridges and grooves allowing the product to be stocked in roll form. A method of providing drainage of moisture from a wall structure is also disclosed.

Description:
TECHNICAL FIELD 
     This invention relates to moisture drainage products and, more particularly, to moisture drainage products intended for incorporation in wall systems and methods for providing moisture drainage in wall systems. 
     BACKGROUND 
     Warm, moisture-laden air can exist in buildings even in buildings in colder climates. A significant amount of moisture can be placed into the air through common household activities, such as cooking, bathing and showering. 
     Especially in colder climates, insulation in a wall structure helps to reduce heat loss from buildings which are heated due to the cold climate. As moisture-laden air passes through the wall structure of such buildings, the moisture-laden air encounters steadily decreasing temperatures. As the air is cooled while moving from the interior of a wall structure to the exterior of the wall structure, the air can eventually reach its dew point and water vapor in the air condenses to form moisture. The result can be a moisture buildup in the wall structure. 
     Vapor barriers are commonly employed on the warm side of wall structures in order to prevent moisture-laden air from entering the wall structure. However, vapor barriers are not usually perfect. In a typical building, multiple penetrations of a vapor barrier can occur, e.g., from electrical and plumbing lines and from windows and doors. 
     If the exterior temperature is cold enough, the moisture existing in the wall structure could eventually turn to frost or ice and, thus, be prevented from draining from the wall structure, at least until the exterior temperature increases. When that happens, however, the moisture can still cause significant damage to the wall structure. 
     Several products exist to allow drainage of moisture from wall structures once the moisture has formed in the wall structure. 
     U.S. Pat. No. 3,654,765, Healy et al, Subterranean Wall Drain, discloses a subterranean wall drain unit including a drain pipe having openings therein and a longitudinally extending planar core defining channels normal to the pipe. A water pervious sheet material covers one face of the core and the openings in the pipe to form a filter therefore. The other face of the core may be covered with a plastic sheet or other vapor barrier. 
     U.S. Pat. No. 3,888,087, Bergsland, Foundation Wall Protective Sheet, discloses improvements in protective membranes or sheets for foundation walls. The sheets have regular courses of protrusions for spacing the sheet from the foundation wall and a porous backing for drainage outwardly of the sheet. The protrusions provide air channels between the protective sheet and the foundation for thermal insulation and for facilitating drying of the foundation wall. Small vertical ribs between the courses of the protrusions provide convenient water passages to take care of drainage water in the porous backing without interfering with the air spaces and incidentally providing bending vertical lines for more facile installation handling. Modifications of the sheet include transverse ribs at lower portions of the sheet to allow horizontal bending thereof wall for footing and drainage configurations. A barrier for preventing back fill falling between the protective sheathing and foundation is also disclosed. 
     U.S. Pat. No. 3,318,056, Thompson, Ventilating Wall Construction With Stud Location Indicators, discloses a sheet of building material placed between wall veneers for moisture protection that includes vertical drainage channels and perforations. 
     U.S. Pat. No. 6,298,620, Hatzinilolas, Moisture Control Panel, discloses a moisture control panel used in exterior walls. A wall constructed with the panel has an inner back-up wall component and an outer wall component of a moisture pervious material, for example, stucco. The moisture control panel is positioned between the two. It has a base sheet on the inner face of the outer wall component. A set of drying perforations slope downwardly toward the inside through this sheet. This drains moisture from the inside of the outer wall component. On the inside, the bay sheet has a set of upwardly sloping bosses which provide an air space on the inside the moisture control panel providing for air circulation and drainage of any moisture. 
     U.S. Pat. No. 4,381,630, Koester, Foundation Vent Structure, discloses a foundation vent structure positioned upon the footings of the building below the lowermost row of concrete blocks of the basement wall and extends below the concrete floor of the basement. The vent structure is formed of a plastic material, preferably in strips, and is shaped to define alternate tunnels and channels having openings therein. The vent structure intercommunicates the openings in the hollow, concrete blocks with the drain area located along the marginal area below the basement wall to permit moisture to be vented into this drain area. 
     However, significant problems exist with such pre-existing products and systems. Such products can prevent the continued movement of moisture of water vapor from the interior to the exterior side of the wall structure where the moisture or water vapor then exits the wall structure and, hence, can cause no further damage. Such products can also become contaminated with other construction materials being used in the formulation of the wall structure or otherwise in the construction of the building. 
     SUMMARY OF THE INVENTION 
     The present invention helps prevent damage from moisture in a wall structure by draining such moisture from the wall structure using ridges and grooves to form vertical channels which allow such moisture to drain. The present invention also allows water vapor and moisture to pass through the product allowing such water vapor or moisture to continue its passage from the interior of the wall structure to the exterior of the building. And further, the present invention prevents other construction materials from contaminating the channels formed by the ridges and grooves permitting moisture to drain in the existing channels. 
     The present invention provides a product adapted to allow drainage of moisture from a wall of a structure. A sheet of corrugated material forms a plurality of ridges and grooves on opposite sides of the sheet of corrugated material. The sheet of corrugated material is relatively inflexible under a force applied generally perpendicular to the sheet. The sheet of corrugated material has a multiplicity of perforations. A sheet of water permeable material is affixed to one side of the sheet of corrugated material. The product is flexible in a direction along the plurality of ridges and grooves allowing the product to be stocked in roll form. 
     In an alternative embodiment, the present invention also provides a wall system for a structure having an interior and an exterior. A plurality of structural members form a structural support for the wall system. Sheathing is placed exterior of the plurality of structural members. A moisture drainage product adapted to allow drainage of moisture from the wall system has a sheet of corrugated material forming a plurality of ridges and grooves on opposite sides of the sheet of corrugated material. The sheet of corrugated material is relatively inflexible under a force applied generally perpendicular to the sheet. The sheet of corrugated material has a multiplicity of perforations. A sheet of water permeable material is affixed to one side of the sheet of corrugated material. The product is flexible in a direction along the plurality of ridges and grooves allowing the product to be stocked in roll form. The moisture drainage product is placed exterior of the sheathing with the ridges and grooves being oriented in a generally vertical direction with the sheet of water permeable material facing the exterior. An exterior veneer is placed exterior of the moisture drainage product. 
     In a preferred embodiment, the plurality of ridges and grooves are parallel. 
     In a preferred embodiment, the corrugated material is a material selected from the group consisting of foils, such as copper, stainless steel and aluminum, plastics, and cellulose materials with a moisture resistant additive. 
     In a preferred embodiment, the corrugated material is a material selected from the group consisting of cementuous and cementuous materials having a reinforced scrim. 
     In a preferred embodiment, the plurality of ridges and grooves in the sheet of corrugated material are evenly spaced. 
     In a preferred embodiment, the sheet of water permeable material comprises polypropylene. 
     In a preferred embodiment, the polypropylene is a spunbond polypropylene. 
     In a preferred embodiment, the sheet of water permeable material comprises a fabric. 
     In another alternative embodiment, the present invention provides a method of providing drainage of moisture from a wall of a structure, the wall having structural members and an exterior veneer. A moisture drainage product is applied to the exterior of the structural members. The moisture drainage product has a sheet of corrugated material forming a plurality of ridges and grooves on opposite sides of the sheet of corrugated material. The sheet of corrugated material is relatively inflexible under a force applied generally perpendicular to the sheet. The sheet of corrugated material has a multiplicity of perforations. A sheet of water permeable material is affixed to one side of the sheet of corrugated material. The product is flexible in a direction along the plurality of ridges and grooves allowing the product to be stocked in roll form. The applying a moisture drainage product step is accomplished with the ridges and grooves of the sheet of corrugated material being oriented in a generally vertical direction with the sheet of water permeable material facing away from the structural members. A veneer exterior is applied exterior of the moisture drainage product. 
     In a preferred embodiment, the veneer exterior is applied exterior to the moisture drainage product with the ridges and grooves of the sheet of corrugated material maintaining an ability to channel to channel moisture along the ridges and grooves. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a plan view of a moisture drainage product constructed in accordance with an embodiment of the present invention; 
         FIG. 2  is a edge view of the moisture drainage product illustrated in  FIG. 1 ; 
         FIG. 3  is a close-up view a portion of the moisture drainage product illustrated in  FIG. 1 ; 
         FIG. 4  is a partial cut-away perspective view of a wall structure incorporating the moisture drainage product illustrated in  FIG. 1 ; 
         FIG. 5  is a perspective view showing the partial installation of the moisture drainage product illustrated in  FIG. 1  installed over sheathing in a wall structure; 
         FIG. 6  is a perspective view showing the partial installation of the moisture drainage product illustrated in  FIG. 1  in a wall structure with lathe installed over the moisture drainage product; and 
         FIG. 7  is a perspective view showing the partial installation of the moisture drainage product illustrated in  FIG. 1  in a wall structure with stucco installed over the lather and the moisture drainage product. 
     
    
    
     DETAILED DESCRIPTION 
     Since the presence of moisture in wall structures of buildings is not uncommon, it is desirable to drain such moisture from the wall structure.  FIG. 1  and  FIG. 2  illustrate a section of moisture drainage product  10  constructed in accordance with an embodiment of the present invention. A sheet of corrugated material  12  is formed from a sheet of plastic material which has been heated and passed through a crimping apparatus producing a series of linear ridges  14  and grooves  16  approximately 3/16 of an inch (0.48 centimeters) deep and approximately 7/16 of an inch (1.11 centimeters) on center. 
     In other embodiments, corrugated material  12  may be constructed from foils, such as copper, stainless steel and aluminum, plastics, and cellulose materials with a moisture resistant additive. 
     As will be discussed with respect to later Figures, linear ridges  14  and grooves  16  of corrugated material  12  form a plurality of channels which, when moisture drainage product  10  is installed in a wall structure with ridges  14  and grooves  16  oriented in a generally vertical orientation, allows moisture which has accumulated in the wall structure to drain, via gravity, from the wall structure. 
     Corrugated material  12  also has a multiplicity of perforations  18  which may be formed in corrugated material  12  either before crimping or after although, in a preferred embodiment, perforations  18  are formed before crimping. 
     Perforations  18  in corrugated material  12  allow moisture, including water and water vapor, to pass through perforations  18 . Perforations  18  allow water vapor which has not condensed in the wall structure to continue to pass outwardly through the wall structure. Further, perforations  18 , since they are water pervious, allow water moisture to pass through corrugated material  12  and be drained from the wall structure with the channels formed by ridges  14  and grooves  16 . 
     A sheet of material  20  is affixed to one side of corrugated material  12 . As shown in  FIG. 1  and  FIG. 2 , sheet of material is affixed to the back side of corrugated material  12 . The primary function of sheet of material  20  is to prevent building materials from accumulating in ridges  14  or grooves  16  on the side of corrugated material  12  having sheet of material  20 . If building materials, in the course of construction, were allowed to accumulate in such ridges  14  and grooves  16 , the channels formed by ridges  14  and grooves  16  could be obstructed by the building material and the drainage ability of the channels formed by ridges  14  and grooves  16  could obfuscated. Sheet of material  20  is also pervious to moisture, including water and water vapor. 
     In a preferred embodiment, sheet of material  20  is constructed of polypropylene, preferably spunbond polypropylene. Alternatively, sheet of material could be constructed of a fabric woven of a moisture resistant material. 
     Sheet of material  20  may be affixed to corrugated material  12  in any suitable manner such as by commonly available commercial construction adhesives. 
       FIG. 3  is a close-up view of a portion of moisture drainage product  10  showing corrugated material  12  including ridges  14  and grooves  16  forming channels, perforations  18  and sheet of material  20 . 
     Corrugated material  12  is constructed of a material which is rigid enough such that, when corrugated with ridges  14  and grooves  16 , is able to withstand commonly encountered construction forces as moisture drainage material  10  is being installed in a wall structure. Examples of commonly encountered construction forces are hammer or automated nailing strikes either affixing moisture drainage product  10  in the wall structure or affixing a later applied material in the wall structure such as the exterior veneer. As an example, an exterior veneer of stucco typically requires a lathe material to be applied exterior to moisture drainage product  10 . The force required by nails or spikes to secure the lathe material to the wall structure should not compromise ridges  14  and grooves  16  to the extent that drainage channels formed by ridges  14  and grooves  16  are obstructed. Similarly, commonly encountered forces involved in shipping, storing and handling of moisture drainage product  10  should also not compromise the drainage channels. In a preferred embodiment, moisture drainage product  10  is able to withstand the weight of a typical construction worker wearing shoes. 
     It will be appreciated that ridges  14  and grooves  16  of moisture drainage product  10  increase the rigidity of moisture drainage product as moisture drainage product  10  is attempted to be bent transverse to ridges  14  and grooves  16 . Thus, ridges  14  and grooves  16  actually increase the rigidity of moisture drainage product  10  and help allow moisture drainage product  10  to withstand normal construction forces. It will also be appreciated that ridges  14  and grooves  16  in moisture drainage product  10  allow moisture drainage product  10  to be less rigid in a direction parallel to ridges  14  and grooves  16 . This relatively less rigidity allows moisture drainage product  10  to be shipped, stocked and stored as a roll stock. Preferably, moisture drainage product  10  can be shipped and stored on 50 foot (15.2 meter) rolls. Alternatively, moisture drainage product could also be shipped, stocked and stored as rigid sheet stock. 
       FIG. 4  is an illustration of wall structure  22  containing moisture drainage product  10 . Starting at the interior side of wall structure  22 , conventional studs  24  form a plane along which sheathing  26  may be affixed. Typically, and optionally, a water barrier  28 , such as #15 roll stock, is applied exterior to sheathing  26 . Moisture drainage product  10  is affixed exterior to water barrier  28  with sheet of material  20  facing outwardly. Sheet of material  20  extends beyond corrugated material  12  on one edge of the roll of moisture drainage product  10 . This edge of sheet of material  20  is used to overlap the next roll of moisture drainage product  10 . The lowest roll of moisture drainage product  10  in wall structure  22  has this edge of sheet of material  20  wrapped under corrugated material  12  to form a bug screen. A veneer for wall structure  22  is applied exterior to moisture drainage product  10 . In one embodiment, the veneer consists of a metal lathe  30  and stucco  32  applied over metal lathe  30 . It is to be recognized and understood that many other forms of exterior veneer are also contemplated including, but not limited to concrete block, brick, natural or man-made stone, and wood siding of all types including wooden lap siding. 
     It can be recognized that without moisture drainage product  10  in wall structure  22  that moisture occurring or accumulating in wall structure  22  can drain through channels created by ridges  14  and grooves  16  in moisture drainage product. Perforations  18  allow moisture drainage product  10  to be water pervious allowing water and water vapor to pass through moisture drainage product  10 . This prevents moisture drainage product from a vapor barrier in the middle of wall construction  22  and actually causing the moisture accumulation it is designed to ameliorate. Further, sheet of material  20  prevents the stucco material  32  from obscuring channels formed in corrugated material  12  on the exterior side of moisture drainage product  10 . 
       FIG. 5 ,  FIG. 6  and  FIG. 7  illustrate a method of constructing wall structure  22 . 
     In  FIG. 5 , wall structure  22  is partially formed with studs  24 , sheathing  26  and roll stock  28 . This is a typical and conventional wall structure construction technique. Typically, studs  24  are installed and then sheathing  26  is affixed to the exterior side of studs  24 . Roll stock  28  is then affixed to the exterior side of sheathing  26 . Studs  24 , sheathing  26  and, optionally, roll stock  28  form the structural components of wall structure  22 . Of course, it is recognized and understood that wooden studs  24 , sheathing  26  and roll stock  28  are just one example of what could comprise the structural components of wall structure  22 . Many other conventional, and unconventional, products, materials and construction could also used. As can be seen in  FIG. 5 , moisture drainage product  10  is then conventionally affixed with construction fasteners exterior to roll stock  28  and sheathing  26 . Note that sheet of material  20  is again placed on the exterior side of moisture drainage product  10 . Thus,  FIG. 5  shows wall structure  22  in a partially completed state with moisture drainage product  10  installed but without an exterior veneer. 
     In  FIG. 6 , the construction of wall structure  22  has taken one more step, the step of partially completing the exterior veneer. In this embodiment, the exterior veneer is stucco. In order to prepare wall structure  22  for stucco material  32 , lathe, preferably metal lathe,  30  is conventionally affixed exterior of moisture drainage product  10 . In  FIG. 7 , stucco  32  can be seen having been applied to lathe  30 . Again, especially since stucco material  32  is semi-liquid when applied to lathe  30  and is intermixed with lathe  30  to give stucco structural integrity, that it is likely that stucco  32  would get into the channels formed by ridges  14  and grooves  16  of corrugated material  12  if it were not for sheet of material  20  which effectively prevents the clogging of the channels formed by ridges  14  and grooves  16 . 
     Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not limited to the illustrative embodiments set forth above.