Patent Publication Number: US-2004045242-A1

Title: Mold and mildew resistant openwork building material

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to a building material, such as an openwork spacer, for forming drainage and ventilation passageways within a wall, roof or like structure of a building to prevent the accumulation of moisture and the growth of mold, mildew, bacteria and other fungi therein. The present invention also relates to a building structure system, or assembly, having the spacer, to a method of assembling a building structure, and to a method of manufacturing an openwork building material.  
       BACKGROUND OF THE INVENTION  
       [0002] Moisture and other substances can accumulate and become trapped within a structure, such as a wall or roof of a building, and cause premature deterioration of the structure. For instance, wind driven rain may penetrate within a wall/roof, or condensation may form within a wall/roof as a result of moisture vapor escaping outwardly of a building through a house-wrap product. Other problems can result from moisture contained in the lumber utilized to construct the wall/roof or from other substances, such as corrosive surfactants, which may leak from certain types of outer siding and roofing materials.  
       [0003] Wall and roof structures of buildings have been assembled with building materials, such as openwork spacers, to combat the problem of moisture accumulation and the like. To this end, the openwork spacer is assembled within the wall or roof structure and provides a network of ventilation and drainage passageways therethrough. Thus, the spacer permits liquids to drain from the structure and ambient air to flow within the structure to evaporate and remove any moisture therein.  
       [0004] An example of a building material for use in providing a path of ventilation in a roof or wall of a building structure is disclosed in U.S. Pat. No. 5,099,627 issued to Coulton et al. and assigned to Benjamin Obdyke, Inc., the assignee of the present application. According to the Coulton patent, an openwork member located between an inner sheathing member and an outer building material provides vapor flow paths therethrough to prevent moisture from becoming entrapped between the inner sheathing member and outer building material. Also see Benjamin Obdyke, Inc.&#39;s commercially available CEDAR BREATHER underlayment spacer product for use with wooden shingle installations.  
       [0005] Benjamin Obdyke, Inc.&#39;s co-pending U.S. patent application Ser. No. 09/934,240 filed on Aug. 21, 2001 discloses another example of an openwork spacer that provides ventilation and drainage passageways between an inner sheathing member and an outer building material of a wall or roof building structure. Still further examples are disclosed by Benjamin Obdyke, Inc.&#39;s commercially available HOME SLICKER ventilation and drainage spacer product, co-pending U.S. patent application Ser. No. 09/875,074 filed on Jun. 6, 2001 and published as U.S. Patent Application Publication No. 2001/0054263 on Dec. 27, 2001, and co-pending U.S. patent application Ser. No. 10/079,020 filed on Feb. 19, 2002.  
       [0006] Other examples of building materials that provide ventilation and/or drainage functions within a building structure are disclosed in U.S. Pat. Nos. 5,826,390 issued to Sacks; 6,131,353 issued to Egan; 6,233,890 issued to Tonyan; 5,598,673 issued to Atkins; 5,860,259 issued to Laska; 4,538,388 issued to Friesen; 4,805,367 issued to Kleckner; 4,315,392 issued to Sylvest; 5,489,462 issued to Sieber; and 5,383,314 issued to Rothberg. The Sacks patent discloses a vapor permeable membrane having spacers thereon for the purpose of providing drainage passageways within a wall of a building, and the Tonyan patent discloses a weather resistive membrane having an attached mesh material which provides open spaces for the flow of moisture downwardly within a wall structure. The Egan patent discloses a drainage mat including a vapor permeable membrane and an openwork mat of filaments having a waffle-like structure. The Laska and Atkins patents disclose products for providing open drainage paths behind masonry walls. The Kleckner, Friesen and Sylvest patents disclose products for providing ventilation within roof structures, and the Sieber and Rothberg patents disclose plastic sheet drainage mats.  
       [0007] The presence of moisture within a wall or roof of a building can lead to the development and growth of mold, mildew and like fungi within wall/roof spaces. The presence of mold spores and the like can create health concerns. For example, in an article titled “Dupont TYVEK Helps Solve Moisture Problems in California Schools” which was recently published on the Internet, it is reported that the presence and discovery of toxic spores within rotting walls have forced school closings. The article suggests the interior wood wall framing, which is made of non-kiln dry lumber, be sprayed with a non-carcinogenic fungicide to pre-empt the growth of any mold or mildew.  
       [0008] Various other patents disclose the use of fungicides in relation to buildings and construction materials. For example, U.S. Pat. Nos. 4,852,316 issued to Webb, 5,224,315 issued to Winter, IV, and 5,729,936 issued to Maxwell disclose prefabricated building panels containing a fungicide. U.S. Pat. No. 5,181,358 issued to Mead discloses a convex siding material provided with an aperture for spraying a fungicide behind the siding material after installation, and U.S. Pat. No. 4,679,380 issued to Rudd discloses a method of treating an existing building structure with an antifungal agent. U.S. Pat. No. 5,698,052 issued to Russo discloses a wallpaper adhesive containing a fungicide and U.S. Pat. No. 5,208,016 issued to Ohmae et al. discloses a method of making a resin composition containing an antimicrobial agent. In addition, U.S. Patent Application Publication No. 2001/0045066 of Nickell et al. discloses blending plastic materials with insect controlling chemical agents and manufacturing building materials therefrom.  
       [0009] Although the drainage and/or ventilation spacer products and other building materials disclosed in the above referenced patents, published patent applications and published article may function satisfactorily for their intended purposes, there remains a need for an improved openwork spacer building material which can be used to form drainage and ventilation passageways within a wall, roof or like structure of a building and which can prevent the accumulation of moisture and the growth of mold, mildew, bacteria and other fungi within the wall/roof structure. Preferably, the spacer should permit ready installation requiring only a minimum of skill, should provide drainage and/or ventilation paths along the inner sheathing member and the outer building material, and should also provide ventilation paths transversely through the spacer. In addition, preferably the spacer should be lightweight and inexpensive to manufacture and should be provided in a form permitting efficient storage and transportation.  
       OBJECTS OF THE INVENTION  
       [0010] With the foregoing in mind, a primary object of the present invention is to provide a building material which is capable of being readily installed in a wall or roof structure between an inner sheathing member and an outer building material and which prevents the accumulation of moisture and the growth of mold, mildew, bacteria and other fungi within the structure.  
       [0011] Another object of the present invention is to provide an openwork spacer material, and a method of making same, that provides a plurality of ventilation and drainage passageways and that provides for the presence of a fungicide or like agent.  
       [0012] A further object of the present invention is to provide a building structure and a method for assembling a building structure having an openwork spacer material therein which prevents moisture from becoming entrapped within the structure and which prevents the growth of mold, mildew, bacteria and other fungi within the structure.  
       SUMMARY OF THE INVENTION  
       [0013] More specifically, the present invention is a spacer-type building material used in the construction of building structures, such as walls and roofs. The spacer is a continuous, indeterminate-length web of material that has an openwork structure and carries an antifungal agent. Thus, when installed within a wall or roof, the openwork spacer prevents growth of mold and mildew and provides an airspace and ventilation and drainage pathways to prevent moisture from being trapped within the building structure thereby preventing deterioration of the building structure. Preferably, the openwork spacer is stored and shipped in a spiral roll and is unrolled during installation.  
       [0014] According to another aspect of the present invention, a method of manufacturing a spacer-type building material is provided. The method includes producing a continuous, indeterminate-length openwork web of material, dispersing an antifungal agent throughout the openwork web of material, and rolling the web of material lengthwise into a spiral roll about an imaginary central axis. In use, the spacer-type building material is unrolled and installed within a building structure, prevents the growth of mold and mildew, and provides an airspace and ventilation and drainage pathways for preventing moisture from being trapped within the building structure and from deteriorating the building structure.  
       [0015] According to still another aspect of the present invention, a method of assembling a building structure is provided. A spiral roll of an elongate web of an openwork material is provided adjacent the inner sheathing of a building structure. The web of openwork material is unrolled and placed along the inner sheathing, and an outer building material is installed relative to the inner sheathing such that a layer of openwork material is sandwiched between the inner sheathing and the outer building material. The openwork material provides an airspace and ventilation and drainage pathways within the building structure to prevent moisture from becoming trapped within the building structure thereby preventing premature deterioration of the building structure, and the openwork material carries an antifungal agent to prevent growth of mold and mildew within the building structure.  
       [0016] According to yet another aspect of the present invention, a building structure is provided having drainage passageways and air spaces therein to prevent moisture from being trapped and to retard deterioration. To this end, the building structure includes an inner sheathing member, an outer building material, and an elongate web of openwork material located between the inner sheathing member and the outer building material. In addition to providing ventilation and drainage passageways and air spaces within the building structure, the openwork material also carries an antifungal agent to prevent growth of mold and mildew within the building structure. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0017] The foregoing and other objects, features and advantages of the present invention should become apparent from the following description when taken in conjunction with the accompanying drawings, in which:  
     [0018]FIG. 1 is an elevational view of a first embodiment of a portion of an openwork spacer according to the present invention;  
     [0019]FIG. 2 is a perspective view of a wall constructed with the spacer of FIG. 1 according to the present invention;  
     [0020]FIG. 3 is a cross-sectional view of the sidewall illustrated in FIG. 2 taken along a plane parallel to the horizontal;  
     [0021]FIG. 4 is a perspective view of a spiral roll of the spacer illustrated in FIG. 1;  
     [0022]FIG. 5 is a cross-sectional view of a roof constructed with the spacer of FIG. 1 according to the present invention;  
     [0023]FIG. 6 is a perspective view of a wall constructed with a second embodiment of a spacer according to the present invention;  
     [0024]FIG. 7 is a perspective view of a spiral roll of the spacer illustrated in FIG. 6;  
     [0025]FIG. 8 is a perspective view of a portion of the openwork spacer illustrated in FIG. 6;  
     [0026]FIG. 9 is a cross-sectional view of the openwork spacer illustrated in FIG. 6;  
     [0027]FIG. 10 is a cross-sectional view of third embodiment of an openwork spacer having a fabric material attached thereto; and  
     [0028]FIG. 11 is a cross-sectional view of fourth embodiment of an openwork spacer constructed of sheet of house wrap material having a plurality of beads adhered thereto at spaced-apart locations.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0029] Referring now to the drawings, FIG. 2 illustrates a wall  10  of a building assembled with a spacer  12 , FIG. 5 illustrates a roof  14  of a building assembled with the spacer  12 , and FIG. 6 illustrates another wall  16  of a building assembled with an alternate spacer  18 . The installed spacers,  12  and  18 , provide ventilation and drainage passageways which enables the free flow of air, vapor and liquids within the wall/roof to ensure that moisture is prevented from accumulating in spaces within the wall/roof. In addition, the spacers,  12  and  18 , carry an antifungal agent, fungicide or the like which provides an additional preventive means for retarding, and/or substantially eliminating, the growth of mold, mildew, bacteria and/or other fungi within the wall/roof.  
     [0030] The structure of the openwork spacer according to the present invention provides a plurality of ventilation and drainage paths so that liquid moisture is permitted to descend within the wall/roof under the force of gravity to an exit provided at the base of the wall/roof and so that a ventilation air flow can pass within the wall/roof to evaporate condensation and other moisture and remove moisture vapor. The specific structure of the openwork spacer can vary as illustrated in the drawings and as discussed below with respect to specific examples. Preferably, the openwork spacer is lightweight, made of minimum of material, and yet is capable of providing an elastically compressible building material that has a suitable compression strength to operate in about a 100 to about a 200 pounds per square foot (psf) environment. For instance, the spacer preferably should compress no more than about 30% of its original manufactured thickness when it is subjected to 100 to 200 psf of pressure. In addition, preferably the openwork spacer is provided in a roll-form as illustrated in FIGS. 4 and 7 to enable efficient storage and transportation.  
     [0031] An important aspect of the present invention is that the spacer carries an antifungal agent, fungicide or the like which prevents the growth of mold, mildew, bacteria and/or other fungi within the wall/roof. Several advantages are provided by such a building material and its use as a carrier of a fungicide. Preferably, the spacer is supplied to the construction site already carrying the fungicide, and the step of installing the spacer simultaneously also accomplishes the step of applying a fungicide within a wall/roof. This eliminates the need to handle fungicide chemicals at the construction site and to apply the fungicide, such as by spraying a liquid fungicide, during construction of the wall/roof. In addition, the spacer can be manufactured such that the fungicide is uniformly dispersed throughout the spacer to ensure that the fungicide is uniformly present throughout a constructed wall/roof including adjacent both an inner sheathing member and an outer building material. Further, if a fungicide is sprayed onto the openwork spacer post-installation, the plurality of drainage/ventilation openings provide the fungicide with numerous locations to adhere so that the fungicide does not merely runoff the sprayed structure.  
     [0032] The antifungal agent, or fungicide, can be applied to the spacer in various manners. For example, the fungicide can be mixed with a raw material utilized to form the spacer. To this end, a fungicide can be added to a molten plastic resin material such that, in the final product, the fungicide exists throughout the material utilized to manufacture the spacer. Alternatively, the fungicide can be coated on fibers or the like utilized to the make the spacer product. Still further, the fungicide can be applied as a coating by spraying or dipping the spacer during or after manufacture of the spacer. The fungicide can also be applied to the spacer at a building site either shortly before or after installation of the spacer within the wall/roof.  
     [0033] By way of example, and not be way of limitation, FIGS.  1 - 5  disclose an openwork building material, or spacer,  12  provided as an elongate, corrugated openwork mat of randomly convoluted polymeric filaments. To this end, the spacer  12  is made of a thin layer of randomly convoluted polymeric filaments that is shaped into a corrugated form during manufacture to provide a corrugated openwork mat having a relatively significant thickness “T” despite containing very little material, ie., polymeric filaments. A fungicide is evenly dispersed and provided within the filaments or on the filaments, or alternatively is applied as a coating on the finished spacer  12 . As illustrated in FIG. 4, the spacer  12  is conveniently and efficiently stored and transported in roll-form in which the spacer  12  is rolled in a spiral about an imaginary central axis “A”.  
     [0034] The wall  10  illustrated in FIGS. 2 and 3 includes an upright planar inner sheathing member  20  which is affixed to support posts  22 . The inner sheathing member  20  is typically formed of panels of plywood, panels of oriented strand board, panels of particle board, an insulated concrete wall, or other materials permitted by local building codes. In some instances, the inner sheathing member  20  is lined with a membrane (not shown), such as a one-way vapor permeable house-wrap. Examples of other membranes include asphalt impregnated felt and building paper.  
     [0035] During construction, the spacer  12  is unrolled laterally on the inner sheathing member  20  and/or membrane, and thereafter, an outer building material  24  is secured a spaced distance from the inner sheathing member  20  such that it overlies the spacer  12  and sandwiches the spacer  12  between the inner sheathing member  20  and the outer building material  24 . The outer building material  24  can be, for instance, a siding material such as a wood or fiber-cement siding product. Of course, other outer building materials can also be utilized, such as, brick, vinyl materials, stucco, exterior insulation finish systems (EIFS), shingles, or any other siding and/or cladding material.  
     [0036] Any moisture which collects on the surface of either the inner sheathing member  20  or membrane, and the outer building material  24  adjacent the spacer  12  is provided with a free unobstructed path to drain downwardly and out of the wall  10 . The multitude of passageways formed in the openwork mat of spacer  12  enable the free circulation of air between the inner sheathing member  20  and outer building material  24  and aid in the drying, or evaporation, of any moisture which is present within the wall  10 . Further, since a fungicide is evenly distributed on and carried by the spacer  12 , and since a layer of the spacer  12  extends throughout the entire wall space, mold and mildew are prevented from growing anywhere within the wall  10 .  
     [0037] As illustrated in FIG. 5, the spacer  12  according to the present invention can also be utilized in roof constructions to provide the same functions as that disclosed above for wall  10 . The inclined roof  14  includes an inner sheathing member, in this case a deck member,  26  which is affixed to rafters  28 . The deck member  26  is typically made of plywood, particle board or other materials permitted by local building codes and is typically lined with a membrane, in this case a layer of roofing felt (not shown). During assembly of the roof  14 , the spacer product  12  is unrolled lengthwise over the roofing felt and is secured to the deck member  26  with nails, staples, adhesives or the like. Thereafter, an outer building material  30  is affixed to the deck member  26  such that it overlies the spacer  12 . As illustrated, the outer building material  30  is wooden shingles, such as cedar shakes. Of course, other building materials can also be utilized, such as, metal, asphalt, tile, rubber or slate roofing materials.  
     [0038] Another example of an openwork building material is disclosed in FIGS.  6 - 9  which disclose a spacer  18  constructed from a solid sheet of thermoplastic material. The thermoplastic material can be, for instance, high impact polystyrene (HIPS), ABS, high-density polyethylene (HDPE), high-density polypropylene (HDPP), PVC, or a blend of any of these suitable polymers and can be shaped by thermoforming, vacuum stamping, or any other suitable technique. Preferably, the material is provided with hollow spacer elements  32  formed in opposite faces,  34  and  36 , of the spacer  18  to provide a plurality of ventilation/drainage passageways adjacent the elements  32  and both faces,  34  and  36 . The thermoplastic material contains a fungicide therein or is applied with a coating of the fungicide. If desired, the thermoplastic material can be perforated to provide a series of ventilation apertures  38  at predetermined spaced distances to permit a transverse path of ventilation through the otherwise solid sheet spacer  18 .  
     [0039] The wall  16  illustrated in FIG. 6 includes an upright planar inner sheathing member  40  which is affixed to support posts  42 . The inner sheathing member  40  can be lined with a membrane (not shown), such as a one-way vapor permeable house-wrap. During construction, the spacer  18  is unrolled laterally on the inner sheathing member  40  and/or membrane, and thereafter, an outer building material  44  is secured a spaced distance from the inner sheathing member  40  such that it overlies the spacer  18  and sandwiches the spacer  18  between the inner sheathing member  40  and the outer building material  44 .  
     [0040] Any moisture which collects on the surface of either the inner sheathing member  40  or membrane, and the outer building material  44  adjacent the spacer  18  is provided with a free unobstructed path to drain downwardly and out of the wall  16 . The multitude of passageways formed in the spacer  18  enable the free circulation of air between the inner sheathing member  40  and outer building material  44  and aid in the drying, or evaporation, of any moisture which is present within the wall  16 . Further, since a fungicide is evenly distributed on and carried by the spacer  18 , and since a layer of the spacer  18  extends throughout the entire wall space, mold and mildew are prevented from growing anywhere within the wall  16 .  
     [0041] Another example of an openwork building material according to the present invention is illustrated in FIG. 10 and includes a mat  46  made of randomly convoluted filaments formed with projections, or hollow spacing elements,  48  which provide the mat  46  with a waffle-like appearance. If desired, a fabric material  50  can be adhered to at least one side of the mat  46  for strengthening and reinforcing the mat  46  and for preventing undesired collapse of the elements  48 . Alternatively, a planar mat (not shown) of randomly convoluted filaments of a given thickness can be utilized such as that disclosed in U.S. Pat. No. 5,099,627 issued to Coulton et al. and assigned to Benjamin Obdyke, Inc. Yet another alternative includes a corrugated thermoplastic sheet spacer (not shown).  
     [0042]FIG. 11 illustrates an additional example of a spacer according to the present invention. It is constructed as a membrane  52  having a plurality of spacer beads  54  adhered thereto at spaced intervals. The membrane  52  can be a one-way vapor permeable house-wrap, a roofing felt, an asphalt impregnated felt, a building paper or the like. The fungicide can be carried by the membrane  52 , beads  54 , or both.  
     [0043] According to another aspect of the present invention, a method of making an openwork building material is provided. To this end, a continuous, indeterminate-length openwork web of material which has a plurality of ventilation and drainage passageways is manufactured. For example, a matting of polymeric filaments can be made by extruding semi-molten plastic filaments onto a profile of the desired spacer and then by permitting the plastic filaments to harden. Alternatively, a sheet of thermoplastic material can be thermoformed, or vacuum thermoformed, into a desired openwork configuration. Alternatively, a membrane material can be extruded and applied with spacer beads.  
     [0044] A fungicide is evenly dispersed throughout the openwork web of material so that the openwork web of material functions as a carrier of the fungicide. In the preferred embodiments, the openwork web of material is pre-loaded with the fungicide so that it carries the fungicide before it is shipped to a building site. For example, a fungicide can be added to a raw material utilized to make the openwork web of material before the openwork web of material is manufactured. Alternatively, the material can be coated with a fungicide at any time before, during, or after the manufacture of the openwork web of material. Yet another alternative includes applying the fungicide to the openwork material at the building site before, or after, installation of the openwork material in a building structure.  
     [0045] After the web of openwork material is manufactured, and before or after the fungicide has been applied, the web of material is preferably rolled lengthwise into a spiral roll about an imaginary central axis. This facilitates handling, storing and shipping of the material. In use, the openwork web of material is unrolled and installed within a building structure to provide an airspace and ventilation and drainage pathways for preventing moisture from being trapped within the building structure. The openwork web of material also functions as a carrier for the fungicide thereby preventing mold and mildew growth in the building structure.  
     [0046] Thus, the above-described spacer, building structure, and method of assembling a building structure according to the present invention provides a cost effective and efficient means for preventing premature deterioration of building structures and for preventing the growth of mold and mildew therein.  
     [0047] While a preferred spacer and method of making same, building structure, and method of assembly have been described in detail, various modifications, alterations, and changes may be made without departing from the spirit and scope of the spacer, building structure, and method of assembly according to the present invention as defined in the appended claims.