Abstract:
A low-emittance material having improved energy efficiency protection against air infiltration and moisture build-up in buildings is disclosed. The aforementioned low-emittance material utilizes existing framing openings or without increasing the wall profile of a building. The present invention provides a low-emittance material which may be implemented on traditional 2×4 framing having R-15 mass insulation material within existing or newly constructed framing cavities. The material of the present invention also meets requirements for serving as a water resistive barrier as defined by ICC AC38.

Description:
PRIORITY 
       [0001]    The present application is a continuation of application Ser. No. 13,107,568, filed on May 13, 2011, which claims priority to provisional patent application entitled, “LOW-E HOUSEWRAP,” filed on May 21, 2010, and assigned U.S. Application Ser. No. 61/346,916. The contents of these applications are incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to building structure materials, and more specifically to an infiltration barrier used in building construction to improve energy efficiency and to protect against air infiltration and moisture build-up in buildings. 
         [0004]    2. Description of Related Art 
         [0005]    In order to improve the energy efficiency of new and existing buildings, it has been common practice in building new structures, and in residing old structures, to cover the exterior wall sheathing with an infiltration barrier, for example, prior to installation of a covering material such as siding. One such infiltration barrier is a high density polyethylene fiber sheeting. While infiltration barriers cut down on drafts and thereby convective heat loss, they provide little other contribution to the energy efficiency of the structure. 
         [0006]    In addition to addressing energy efficiencies of new and existing buildings, moisture concerns can be one of the worst enemies of home or building construction. Water or moisture or humid air infiltration if allowed to penetrate behind siding or brick can saturate the wood of a building structure, thereby creating an environment that encourages mildew or rot. A weather resistant barrier has for many years been applied to the wood studs of buildings and homes in order to resist the moisture or water generated by weather. Such material is typically flexible and in a film or sheet form. Typically, this weather resistant barrier or “house wrap” is applied to the wooden stud frame before the application of a final siding or veneer (e.g. brick, metal, painted wood). Many such “wrap” products are commercially available such as, for example: Dupont Tyvek®, Typar®. Housewrap (www.typarhousewrap.com), and Barricade®. building wrap (www.ludlowcp.com). 
         [0007]    In 2010 the International Energy Conservation Code (IECC) and International Residential Code (IRC) increased the thermal performance requirements for residential walls. Both of these standards seek to improve thermal performance and reduce energy needs per dwelling. As of January 2010 the U-value requirement for geographical area or zones 5-8 is 0.057; the reciprocal R-value for wall systems is R-20. The U-factor is the inverse, or reciprocal, of the total R-Value, i.e.: U-factor=1/Total R-Value. The R-Value is the thermal resistance to heat flow. A larger R-Value means that the material has greater thermal resistance and more insulating ability as compared to a smaller R-Value. Such R-Values can be added together. For instance, for homogeneous assemblies, the total R-Value of an insulation assembly is the sum of the R-Value of each layer of insulation. These layers may include sheathing and finishes, the insulation itself, air films and weatherproofing elements. 
         [0008]    In order to meet the new building requirements, builders have employed additional building techniques such as altering construction of framed openings. For example, typically, builders have constructed walls on 2×4 framing. However, due to the revised requirements, builders are altering building designs by constructing walls on 2×6 framing and inserting, for example, R-20 mass insulation within the respective wall cavity in order to meet the energy/code regulations mandated within the building industry. These techniques, however, increase construction costs because of the added and more expensive construction materials. In addition, the increased size of framing also produces a loss in living space. Nevertheless, many builders have simply accepted the added cost and loss of living space created by the newly implemented thermal code changes. 
         [0009]    Accordingly, a need exists for providing a protective wrap that improves energy efficiency and protection against air infiltration and moisture build-up in buildings while satisfying newly implemented industry-wide energy/code regulations. There is also a need for employing a protective wrap which meets or exceeds the newly implemented code requirements on existing framing structures or openings and/or without increasing the wall profile of a building. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention provides a low-emittance housewrap material which may be implemented on traditional 2×4 framing having R-15 mass insulation material within existing or newly constructed framing cavities. The material of the present invention also meets requirements for serving as a water resistive barrier as defined by The International Code Council&#39;s (ICC) codes and standards used to construct residential and commercial buildings, including homes and schools (e.g., ICC AC38). Thus, by not increasing the wall profile in the attempt to meet new industry standards, the builder does not have to perform additional techniques or provide additional expenses for constructing framed openings. 
         [0011]    Still other aspects, features and advantages of the present invention are readily apparent from the following detailed description, simply by illustrating a number of exemplary embodiments and implementations, including the best mode contemplated for carrying out the present invention. The present invention also is capable of other and different embodiments, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present invention will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments, but are for explanation and understanding only. 
           [0013]      FIG. 1  provides a top view of a low-emittance housewrap material according to an exemplary disclosed embodiment; 
           [0014]      FIG. 2  provides a cross-sectional view of a low-emittance housewrap material according to an exemplary disclosed embodiment; 
           [0015]      FIG. 3  provides a cut-away perspective view of a low-emittance housewrap material according to an exemplary disclosed embodiment; 
           [0016]      FIG. 4  provides a top view of a low-emittance housewrap materials during an assembly method according to an exemplary disclosed embodiment; 
           [0017]      FIG. 5  provides a perspective view of the low-emittance housewrap materials during the assembly method of  FIG. 4 ; 
           [0018]      FIG. 6  provides a top view of a low-emittance housewrap materials during a continued assembly method according to an exemplary disclosed embodiment; 
           [0019]      FIG. 7  provides a perspective view of the low-emittance housewrap materials during the assembly method of  FIG. 6 ; 
           [0020]      FIG. 8  provides a top view of low-emittance housewrap materials after assembly according to an exemplary disclosed embodiment; 
           [0021]      FIG. 9  provides a bottom view of low-emittance housewrap materials prior to assembly according to an exemplary disclosed embodiment; 
           [0022]      FIG. 10  provides a top view of low-emittance housewrap materials during an assembly method according to an exemplary disclosed embodiment; 
           [0023]      FIG. 11  provides a bottom view of low-emittance housewrap materials after assembly according to an exemplary disclosed embodiment; 
           [0024]      FIG. 12  provides an exemplary exterior wall according to an exemplary disclosed embodiment; and 
           [0025]      FIG. 13  provides a low-emittance housewrap material application to the exemplary wall structure of  FIG. 12  according to an exemplary disclosed embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    A low-emittance housewrap is described. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the exemplary embodiments. It is apparent to one skilled in the art, however, that the present invention can be practiced without these specific details or with an equivalent arrangement. 
         [0027]    Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,  FIG. 1  illustrates a top view of low-emittance housewrap materials according to one disclosed embodiment of the present invention. By way of example, two pieces of the low-emittance housewrap materials  10 ,  12  are shown. Each of the two pieces of low-emittance housewrap materials  10 ,  12  may comprise flap portions  14 ,  16 , respectively, at one end thereof. At another end the low-emittance housewrap material may include an adhesive strip  18  such as that provided on low-emittance housewrap material  10 . In a preferred embodiment, the top surface  20 ,  22  of the low-emittance housewrap materials  10 ,  12 , respectively, is a reflective material such as a layer of reinforced foil material. 
         [0028]    Turning to  FIG. 2 , a cross-section of the low-emittance housewrap material  12  is shown. The low-emittance housewrap material  12  may comprise an assembly of product component parts including, for example, a reflective foil material  34 , foil reinforcement  26 , and a foam material  28 . In one embodiment, the reflective material may comprise a facing of approximately 99.4% polished aluminum. It is noted that the reflective material may comprise a facing having any suitable amount of aluminum, for example, greater than about 90%, preferably between about 90% and about 99.9%, even more preferably between about 99.0% and about 99.9%. The reflective foil material  34  may be nonreinforced on one side. On the other side, the reflective foil material  34  may comprise a foil reinforcement  26  including, for example, a scrim foil reinforcing  30  (e.g., see  FIG. 3 ). Scrim is a term known in the art to consist of crossed lines of plastics material which serve to strengthen the overall product and to prevent stretching damage to the layers. The reflective foil material  34  and foil reinforcement  26  may be applied over and bonded to the foam material  28 . The scrim foil reinforcing  30  is sufficient to provide a tensile strength of approximately 23 pounds per inch width in a machine direction and 25 pounds per inch width in a cross machine direction on a low-emittance housewrap material test specimen cut approximately 1″ wide by 9″ long in standard ambient lab conditions. The foam material  28  serves as a polyolefin thermal break such as one comprising a closed cell polyethylene foam. In a preferred embodiment, the nominal thickness of the polyolefin thermal break is approximately ¼″ (0.25″). It is noted that the nominal thickness of the polyolefin thermal break may be any suitable thickness, for example, greater than about ⅛″ (0.125″) and less than about ⅜″ (0.375″). Thicknesses above about ¼″ are within the scope of the present invention. It is noted that a thickness greater than about ¼″ may require use of 2×6 framing instead of the more traditional 2×4 framing. The low-emittance housewrap  12  may also incorporate a self adhered drainage plane  24  feature as further described below. 
         [0029]    Thus, the invention includes a layer of polyethylene foam which serves as a support for the other added component layers. Polyethylene foam or equivalent polypropylene foam may be utilized, both being in the chemical family designated as polyolefins. A thin layer of aluminum foil is bonded indirectly to one or both sides of said foam layer. Thin polyethylene layers are placed between the aluminum foil and the foamed layer. The thin polyethylene is bonded to the aluminum foil layer to greatly improve its resistance to tearing. This strengthening feature means that the end product has a much wider use than has been known in the art. A layer of strengthening scrim may be added to further enhance the product integrity. In practice of the invention, the various layers adjoin one another after being flame or heat roller laminated together. 
         [0030]    In certain embodiments and in practice of the invention, both sides of the foam layer may be covered with layers as described above. The end product may thus appear identical on either side with the aluminum foil layers being externally located. Thus, use and installation is simplified since the product may be used with either side facing out since both external faces are identical. The resulting bonded layers are easily rolled, transported and installed without requiring special tools or environmental precautions which must be taken with many other prior art insulations. 
         [0031]    Turning to  FIG. 3 , the low-emittance housewrap  12  comprises perforations  32  sufficiently spaced to ensure that the low-emittance housewrap material does not act as a vapor barrier. In one preferred embodiment, the perforations in the low-emittance housewrap are generated from perforation system consisting of 1/16″ punchers placed in four holes per 1.25 square inch sequence on a collar mechanism. The collar mechanism is mounted to a drive roll assembly for perforation of the low-emittance housewrap wherein a 1.25 square inch perforation pattern is achieved on the finished product. A perforation pattern of 1.25 square inch allows low-emittance housewrap  12  to meet the criteria for perms, water vapor transmission and water resistance while maintaining an effective emissivity rating. This is unique and contrary to industry standards wherein in many applications, micro perforations are generated in housewraps using needles for vapor penetration. However, in such convention applications, the micro perforations are susceptible to resealing when exposed to higher temperatures. This affect may trap moisture and induce undesirable results such as mold and rot. In contrast, the present perforation pattern of the prescribed invention eliminates the possibility resealing when exposed to higher temperatures. Spaced in approximately 1.25″ square perforations, the low-emittance housewrap material achieves a preferred permeance and water vapor transmission of approximately 7 perm or 40 g/day/m 2 . As such, the present low-emittance housewrap material performs within the optimal permeance and water vapor transmission range of about 5 to about 20 perm. 
         [0032]    The present low-emittance housewrap material meets the Standard Specification for Reflective Insulation, C 1224-03, Section 6, 6.1, which states that “Low emittance materials shall have a surface with an emittance of 0.10 or less, in accordance with test Method C 1371.” Specifically, the present low-emittance housewrap material achieves an emittance of 0.10 or less, more specifically within a range of about 0.03 to about 0.05, in accordance with test Method C 1371. 
         [0033]    Accordingly, the product low-emittance housewrap material of the present invention is constructed to include the following approximate performance characteristics: 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
               
                   
                 Test Description 
                 Test Results 
               
               
                   
                   
               
             
             
               
                   
                 Perm Test 
                 7 perms 
               
               
                   
                 ASTM E-96 
                   
               
               
                   
                 Water 
                 As Received 23 hrs 
               
               
                   
                 Resistance 
                 Pass 
               
               
                   
                 ASTM D-779 
                 Weathered 23 hrs 
               
               
                   
                   
                 Pass 
               
               
                   
                 Ultraviolet light  
                 No Cracking 
               
               
                   
                 Accelerated Aging 
                 No Cracking 
               
               
                   
                 Tensile Strength 
                 23 lbs/inch 
               
               
                   
                   
                 (machine direction) 
               
               
                   
                   
                 25 lbs/inch 
               
               
                   
                   
                 (cross direction) 
               
               
                   
                 U-value 
                 .056 vinyl 
               
               
                   
                 Wall (zone 5-7) 
                   
               
               
                   
                 2010 IECC 
                   
               
               
                   
                 U-value 
                 .051 brick 
               
               
                   
                 Wall (zone 5-7) 
                   
               
               
                   
                 2010 IECC 
                   
               
               
                   
                 U-value 
                 .063 Stone 
               
               
                   
                 Wall (zone 5-7) 
                   
               
               
                   
                 2010 IECC 
               
               
                   
                   
               
             
          
         
       
     
         [0034]    Although the use of 1/16″ punchers at a rate of four holes per 1.25 square inch is described above and represents one of many preferred embodiments of the present invention, other size punchers may be used and other rates of holes per given area are within the scope of the present invention. For example, the diameter of the puncher may be varied to any suitable size and the rate may be modified to achieve the particular permeance and emittance standards required by a particular building code, specification or other requirement. 
         [0035]    The system U-values described in The Evaluation of Thermal Resistance of a Building Envelope Assembly demonstrates the performance of wood framed walls (2×4 construction 16″ on center). The U-value calculations are based on methods outlined by the ASHRAE Handbook of Fundamentals. The U-value performance of these systems achieve a U-value between 0.051 (brick), 0.056 (vinyl) and 0.063 (stone) satisfying or exceeding requirements for zones 1-7 established by 2010 IECC Code Table 402.1.3 or equivalent UA alternative values established by other code bodies. 
         [0036]    Flap portion  16  is illustrated in  FIG. 3 . This overlapping flange serves as a self adhered drainage plane  24 . During assembly of one or more low-emittance housewrap sections, the flap portion  16  may be assembled to cover an edge of an abutting portion of another low-E housewrap material section in order to seal the edge. For example, turning to  FIGS. 4 and 5 , a first section  10  of low-emittance housewrap material is positioned near a second section  12  of low-emittance housewrap material. The flap portion  16  of the second section  12  of low-emittance housewrap material may be disposed over an edge portion  38  of the first section  10  of low-emittance housewrap material. In one embodiment, the aforementioned edge portion  38  may include an adhesive strip  18  for retaining the flap portion  16  thereon. The adhesive strip  18  may be employed on the top surface  20  such as on the reflective foil material  34 . While the adhesive strip  18  has been described and shown in the drawings for illustrative purposes, any means may be employed which is suitable for retaining the flap portion  14  over the edge portion  38  in order to provide a water resistive barrier between the abutting sections of low-emittance housewrap materials. 
         [0037]    Turning to  FIGS. 6 and 7 , a protective film is removed to expose the adhesive strip  18  in preparation for securing the flap portion  16  over the edge portion  38 . The flap portion  16  is contacted to the adhesive strip  18  and secured over the edge portion as illustrated in  FIG. 8 . This assembly serves to provide a water resistive barrier between two abutting sections of low-emittance housewrap materials of the present invention to effectively seal their respective edges and allow water runoff from one low-emittance housewrap material section to another low-emittance housewrap material section. 
         [0038]    A bottom view vantage point of abutting low-emittance housewrap materials is illustrated in  FIGS. 9-10 . Again, the first section  10  of low-emittance housewrap material is positioned near the second section  12  of low-emittance housewrap material. The flap portion  16  of the second section  12  of low-emittance housewrap material is disposed over an edge portion  38  of the first section  10  of low-emittance housewrap material. Edge portion  38  may include an adhesive strip  18  for retaining the flap portion  16  thereon. As a sufficient force is applied, for example, to flap portion  16  to contact the adhesive strip  18 , the flap portion  16  is held in retention over the edge portion  38  as shown, for example, in  FIG. 11 . It is clear from  FIG. 11  that, in a final assembly arrangement, a foam edge portion  56  of a first low-emittance housewrap material  10  abuts a foam edge portion  58  of a second low-emittance housewrap  12 . Accordingly, the assembled sections serve to provide a water resistive barrier between two abutting sections of low-emittance housewrap materials of the present invention. 
         [0039]    In order to improve the energy efficiency of new and existing building structures, application of the herein described low-emittance housewrap serves to cover the exterior wall sheathing with an infiltration barrier, for example, prior to installation of a covering material or exterior finish such as siding, brick, stone, masonry, stucco and concrete veneers, for examples. The herein described low-emittance housewrap also serves to protect against air infiltration and damaging moisture build-up. Air infiltration may occur in typical construction through, among other places, sheathing seams and cracks around windows and doors. Moisture build-up can occur externally in the wall cavity from, for example, leaking exterior finishes or coverings, and cracks around windows and doors. The low-emittance housewrap of the present invention does not trap the water, but rather allows it to flow downward so as to exit the wall system. 
         [0040]    Installation procedures of the presently described low-emittance housewrap include those as described, for example, in the technical manual for ESP Low-E® Housewrap utilized on exterior walls and under a primary barrier. The technical manual for ESP Low-E® Housewrap is submitted herewith and is hereby fully incorporated herein by reference. Turning to  FIG. 12 , an exemplary exterior wall assembly  40  is constructed and prepared for receiving the low-emittance housewrap material of the present invention. In the illustrated example, a window opening  42  is shown. In a preferred embodiment, the low-emittance housewrap is employed after the walls have been construction and all sheathing and flashing details have been installed. The low-emittance housewrap material is preferably applied before doors and windows have been set inside framed openings and prior to the installation of the primary wall covering. 
         [0041]    Turning to  FIG. 13 , a first low-emittance housewrap material is applied to the wall assembly  40 . The reflective side of the low-emittance housewrap material is installed facing outwardly. In one preferred embodiment, a roll of low-emittance housewrap material is unrolled horizontally starting at the corner of a preferred exterior wall  40 . The flange side or flap portion (e.g.,  14 ,  16  of  FIG. 1 ) of the roll is installed facing downwardly. The low-emittance housewrap material is secured to the exterior wall with fasteners  48  such as staples or cap nails (or any other suitable fasteners) at preferably every 8-12″. When applying another horizontal run of low-emittance housewrap material  44 , the foam ends of each applied section of rolled low-E housewrap material abut together such that the flange  52  of the additionally applied low-emittance housewrap material  44  is allowed to overlap the outside edge  50  of the adjacent low-emittance housewrap material  46 . This installation ensures that any intruding water is encouraged by the drainage plane (e.g.,  24  of  FIG. 2 ) to flow downwardly. 
         [0042]    In a preferred embodiment, the flange  52  is installed to overlap the abutting foam edge by approximately 2″. The low-emittance housewrap material is installed to extend over all of the sill plates by a minimum of approximately 1″. The vertical and horizontal seam areas are sealed with suitable low-emittance foil tape. The low-emittance housewrap material may be trimmed around each framed opening with additional appropriate detailing applied as per window/door manufacturer and/or code standards. 
         [0043]    Once installed, an appropriate exterior covering may be applied/installed over the low-emittance housewrap. Such covering may include, but not limited to, siding, brick, stone, masonry, stucco and concrete veneers. The utilization of the herein described low-emittance housewrap provides, inter alia, a protective wrap that not only improves energy efficiency in accordance with newly implemented industry-wide energy/code regulations, but enhances drainage of damaging moisture build-up while protecting against air infiltration. 
         [0044]    Moreover, other implementations of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. Various aspects and/or components of the described embodiments may be used singly or in any combination. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.