Patent Publication Number: US-2006010788-A1

Title: Pre-molded corner flashing for use with sealing members

Description:
RELATED APPLICATIONS  
      This application claims the benefit of U.S. Provisional Patent Application No. 60/578,247 entitled MOLDED CORNER WINDOW FLASHING FOR USE WITH SEALING TAPE, filed Jun. 9, 2004, and hereby fully incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates to exterior-type flashing for static structures, such as buildings and home. More particularly, the present invention relates to an interior corner flashing system for window and door openings in walls.  
     BACKGROUND OF THE INVENTION  
      The problems with water leaking into building structures are well known. Various types of flashing and sealing arrangements have been developed for different parts of a building structure to address these problems.  
      Flashing for use in roofing is the most common example. U.S. Pat. Nos. 5,018,333 and 5,913,779 describe folded flashing members for exterior corners of skylights installed in a roof. U.S. Pat. No. 6,681,530 describes a one-piece roof flashing for exterior corners, such as around chimneys, where the angles of three surfaces are sloped at an angle other than 90 degrees in order to match the slope of the roof.  
      Another example is the use of flashings around corners of masonry walls. U.S. Pat. Nos. 4,700,512 and 6,122,874 describe flashings that are folded or pleated for use with exterior masonry corners. U.S. Pat. No. 5,815,986 describes a two-piece flashing member for use on an interior corner for masonry wall openings.  
      With the continued improvements in watertight construction of windows and doors and with the widespread use of house wrap materials like Tyvek®, it is now common for some kind of sealing treatment to be applied to the wall openings for windows and doors. Most of these treatments focus on sealing along the length of the top, bottom and sides of the wall opening. While caulking is sometimes used, a more common approach is to use a strip of pre-creased sealing tape that is secured to the edge of the opening and to the adjacent wall. A similar approach is described in U.S. Pat. No. 6,305,130 and U.S. Pat. Publication No. 2003/0056444A1 that describe an L-shaped window flashing strip with inner lip that fits into rough opening and outer flap that is adhered to wall surrounding rough opening. Another example of this approach is shown in U.S. Pat. No. 6,244,001 that describes a strip of window flashing comprised of three panels connected along a common edge and radiating outward.  
      The problem with these strip-based approaches is how to best handle the interior corners in the wall opening. Conventionally, an overlapping technique is used that overlaps the piece of tape or strip running along the bottom edge with the piece of tape or strip running along the side edge. For example, in U.S. Pat. No. 6,305,130, sealing of the corners of the rough wall opening with the L-shaped strip is addressed by overlapping the outer flaps of adjacent flashing strips. The disadvantage with this approach is that a seam is created at the corner where these two strips meet that can be prone to leaking.  
      To address this problem, a flexible sealing tape can be used, with a continuous run of tape wrapped around the interior bottom corners of a window opening. While generally effective, the flexible sealing tape is significantly more expensive than conventional pre-creased straight sealing tape. The flexible nature of the sealing tape also makes the tape more difficult to work with and therefore more likely to have problems caused by improper installation.  
      Other solutions for sealing the interior corners of window and wall openings have been proposed. U.S. Pat. No. 5,899,026 describes a fiberglass mesh window flashing sealed by elastomeric liquid flashing material that is applied to the fiberglass mesh once the mesh is installed in a window opening. U.S. Pat. No. 6,401,402 describes a pre-folded clay coated polyethylene sheet for flashing interior window corners.  
      While there are existing solutions for sealing interior corners of window and wall openings, it would be desirable to provide a better solution for sealing and flashing the interior corners of window and wall openings that could improve on the existing solutions for flashing window and wall openings in terms of price, performance and ease of installation.  
     SUMMARY OF THE INVENTION  
      An interior corner flashing system for window and door openings in walls utilizes a combination of conventional sealing tape or members with a pre-formed corner flashing member made from polymer material in a single continuous seamless piece to provide for an effective and economical solution for sealing an interior corner of a wall opening. The pre-molded corner flashing member has interior flashing portions that meet at an interior corner to conform with a corner of the rough opening, and a membrane flashing portion intersecting each of the interior flashing portions along separate exterior corners, the interior and exterior corners intersecting at a common point. Preferably, the two interior flashing portions of the pre-molded corner flashing member are equilateral and have a width appropriate for a width of the wall so that the corner flashing member can be used on either a left or right interior corner of the rough opening. The interior corner of the opening may be sealed by placing the molded corner flashing member in the corner and then running a strip of pre-creased sealing tape or other sealing member along the periphery of the wall opening and overlapping a portion of the sealing member on both the interior flashing portion and the membrane flashing portion.  
      According to an embodiment of the invention, a flashing system for an opening in an exterior wall of a structure includes a pre-formed corner flashing member made from polymer material in a single continuous seamless piece. The flashing member includes a pair of generally planar interior flashing portions each presenting a front and an opposing back side, and a generally planar membrane flashing portion presenting a front and an opposing back side. The pair of interior flashing portions intersects along a first corner presenting a first corner axis, the membrane flashing portion intersects one of the pair of interior flashing portions along a second corner presenting a second corner axis, and the membrane flashing portion intersects the other of the pair of interior flashing portions along a third corner presenting a third corner axis, so that the first, second, and third corner axes intersect at a common point. When the corner flashing member is positioned in the interior window or door opening corner with the back side of the membrane flashing portion confronting the exterior surface of the wall exterior membrane and the first corner axis extending along the interior opening corner, the back sides of each of the interior flashing portions confront a separate one of the pair of inwardly facing surfaces defining the opening and the second and third corner axes extending along the periphery of the opening. The system further includes at least a pair of adhesive sealing members for flashing the periphery of the opening on either side of the corner flashing member. Each sealing member sealingly engages with the membrane flashing portion and one of the interior flashing portions of the corner flashing member.  
      In another embodiment of the present invention, a method of installing a window in an opening defined in an exterior wall of a structure includes providing a pair of corner flashing members formed from polymer material. Each corner flashing member includes a pair of generally planar interior flashing portions each presenting a front and an opposing back side, and a generally planar membrane flashing portion presenting a front and an opposing back side. The pair of interior flashing portions intersects along a first corner presenting a first corner axis, the membrane flashing portion intersects one of the pair of interior flashing portions along a second corner presenting a second corner axis, and the membrane flashing portion intersects the other of the pair of interior flashing portions along a third corner presenting a third corner axis so that the first, second, and third corner axes intersect at a common point. The interior flashing portions and the membrane flashing portion are integrally formed together in a single, seamless continuous piece. The corner flashing members are positioned in a separate interior corners of the rough opening with the back side of the membrane flashing portion confronting the exterior surface of the wall exterior membrane, the first corner axis extending along the interior opening corner, the back sides of each of the interior flashing portions confronting a separate one of the inwardly facing surfaces defining the opening and the second and third corner axes extending along the periphery of the opening. The periphery of the opening between the corner flashing members is flashed with a first length of sealing tape with a portion of the sealing tape overlapping the membrane flashing portion and one of the interior flashing portions of each corner flashing member. The window is then secured in the opening after the flashing is completed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a fragmentary perspective cut-away view of a frame wall section including a window rough opening according to the prior art;  
       FIG. 2  is an isometric view of a pre-molded corner flashing member according to an embodiment of the present invention;  
       FIG. 3  is a side elevation view of the corner flashing member of  FIG. 2  depicting the back side of the interior flashing portion;  
       FIG. 4  is a rear elevation view of the corner flashing member of  FIG. 2 ;  
       FIG. 5  is a fragmentary perspective cut-away view of a frame wall section including a window rough opening with corner flashing members according to an embodiment of the present invention  FIG. 6  is a fragmentary perspective cut-away view of the frame wall section depicted in  FIG. 5  with sealing tape positioned between the corner flashing members to seal the bottom of the rough opening according to an embodiment of the present invention;  
       FIG. 7  is a fragmentary perspective cut-away view of the frame wall section depicted in  FIG. 6  with sealing tape sealing the vertical periphery of the rough opening and with corner flashing members positioned in the upper corners of the opening; and  
       FIG. 8  is a fragmentary perspective cut-away view of the frame wall section depicted in  FIG. 7  with a window secured in the opening.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring to  FIG. 1 , a section of typical frame building construction having a window rough opening defined therein is depicted with portions cut away to show the various components. Wall  10  generally includes frame  12 , interior membrane  14 , exterior membrane  16 , and exterior wall covering  18 . Frame  12  generally includes one or more horizontal plates  20  positioned along the top and bottom of wall  10  with a plurality of vertical stud members  22  extending therebetween. Window rough opening  24  is framed at the bottom with a generally horizontal sill  26  and at the top with a generally horizontal header  28 . Sill  26  and header  28  along with studs  22  on either side of opening  24  present generally inwardly facing surfaces  29 , which intersect at interior corners  29   a  and define periphery  29   b  of opening  24 . Plates  20  and studs  22  are typically wood, but may also be metal sections, particularly where wall  10  is not load-bearing. Interior membrane  14  is typically one or more layers of gypsum wallboard or plaster, but may also be any other suitable material such as wood paneling.  
      Exterior membrane  16  is a generally continuous layer of material within wall  10  that may function to retard the flow of air through interstitial openings in wall  10 , and that may also function as a water resistant barrier to intrusion of bulk water or moisture into wall  10  from the exterior. Membrane  16  presents an exterior surface  30 , and generally includes one or more layers of sheathing  32  and a layer of wrap material  34 . Sheathing  32  is typically oriented strand board (OSB) or plywood in light construction, but may also be gypsum sheathing, extruded polystyrene foam, asphalt impregnated fiber board, cement board, or any other suitable sheathing material. Wrap material  34  is typically thin spun bonded polyolefin sheeting such as Tyvek®, but may also be any other thin material suitable for use in wall construction, such as asphalt impregnated felt or other building paper material. At wall openings, such as window rough opening  24 , wrap material  34  may be either wrapped inwardly into the opening and terminated on the inwardly facing surface  29  of opening  24  as depicted in  FIG. 1  along side edge  36  or may be terminated at the opening edge with wrapping inwardly, as depicted in  FIG. 1  along bottom edge  38 . Exterior wall covering  18  is generally applied as a finish layer to wall  10 , and may include wood, plastic, or metal siding, stucco, masonry products such as brick, or any other material suitable for the exterior of a structure.  
      Referring to  FIG. 2 , a pre-molded corner flashing member  40  according to an embodiment of the present invention is depicted. Corner flashing member  40  generally includes a pair of interior flashing portions  42 ,  44 , and a membrane flashing portion  46 . Interior flashing portions  42 ,  44 , intersect along an interior corner  48 , which presents a first corner axis denoted A-A in the drawing. Membrane flashing portion  46  intersects each of interior flashing portions  42 ,  44 , along exterior corners  50 ,  52 , presenting second and third corner axes, denoted B-B and C-C in the drawing, respectively. Corner axes A-A, B-B, and C-C, intersect at a single point  54  coplanar with membrane flashing portion  46 .  
      Interior flashing portions  42 ,  44 , may be positioned at substantially a right angle relative to each other to conform with the right angle corners of a typical window or door rough opening. Similarly, membrane flashing portion  46  may be positioned at substantially a right angle to each of interior flashing portions  42 ,  44 , to conform with the right angle edges along the periphery of a typical window or door rough opening. It will be appreciated, however, that interior flashing portions  42 ,  44 , and membrane flashing portion  46 , may be positioned at any desired angle relative to each other to conform with window or door opening corners that do not form right angles.  
      In an embodiment of the invention, interior flashing portions  42 ,  44 , are generally rectangular or square with dimensions preferably in a range of about two (2) to eight (8) centimeters, and more preferably about five (5) centimeters. In turn, membrane flashing portion  46  may be generally equilateral L-shaped with dimensions preferably in a range of about four (4) to sixteen (16) centimeters, and more preferably about ten (10) centimeters. Corners  56  of interior flashing portions  42 ,  44 , and corners  58  of membrane flashing portion  46  may be radiused as depicted in  FIG. 2 , with a preferable radius dimension of about one (1) centimeter, to inhibit penetration of the sealing tape by sharp corners of corner flashing member  40 . These radiused corners may also enable more of the sealing tape to adhere to exterior surface  30  of membrane  16  or inwardly facing surfaces  29  of rough opening  24 . Interior corner  48  may also be radiused, with a preferable radius dimension of about four (4) millimeters.  
      In an embodiment, corner flashing member  40  is made from UV stabilized polymer material and is molded or vacuum formed into the desired shape in a single, seamless, continuous piece. The thickness of interior flashing portions  42 ,  44 , and membrane flashing portion  46  is in a range of from about 0.01 millimeters to about 0.25 millimeters.  
      In an embodiment, texturing or surface patterns are provided on all or portions of front side  60  of interior flashing portions  42 ,  44 , and front side  62  of membrane flashing portion  46  to enhance adhesion with sealing tape. Further, a tacky substance such as glue or other adhesive may be applied to back sides  64  of interior flashing portions  42 ,  44 , and back side  66  of membrane flashing portion  46  to temporarily hold the corner flashing member in position in the corner of a rough opening without the need for penetrating fasteners, which may lead to leaking at the point of penetration.  
      As depicted in  FIGS. 5-8 , corner flashing member  40  may be used in connection with conventional sealing tape during the installation of exterior windows  68  or doors (not shown) in rough opening  24  of wall  10  to inhibit intrusion of water and moisture to wall  10  from the exterior. Corner flashing member  40  provides for a seamless corner  70  that joins inwardly facing surfaces  29  of rough opening  24  to exterior surface  30  of membrane  16 .  
      In an embodiment, corner flashing member  40  is positioned in both bottom left corner  72  and bottom right corner  74  of rough opening  24  with back side  66  of membrane flashing portion  46  confronting exterior surface  30  of membrane  16 , first corner axis A-A extending along interior opening corner  29   a , back sides  64  of interior flashing portions  42 ,  44 , confronting a separate inwardly facing surfaces  29  and second and third corner axes B-B, C-C, extending along periphery  29   b  of rough opening  24  as depicted in  FIG. 5 . Bottom corners,  72 ,  74 , of rough opening  24  are generally where water and moisture most often penetrate into wall  10 . Corner flashing members  40  may also be similarly positioned in upper corners  76  of rough opening  24  as depicted in  FIG. 7  if desired. As depicted in  FIG. 6 , a first length  76  of sealing tape may then be positioned as a sealing member  78  extending between corner flashing members  40  along periphery  29   b  of rough opening  24  at bottom edge  38 , overlapping onto interior flashing portion  44  and membrane flashing portion  46  of each corner flashing member  40 . Sealing member  78  adheres and seals to both corner flashing members  40 , exterior surface  30  of membrane  16  and inwardly facing surface  29  to form a “pan flashing” at the bottom of rough opening  24 , effecting a “pan” or “dam” effect to divert water to the exterior wall surface and away from the interior wall cavities. Thus, when used in connection with sealing member  78 , corner flashing members  40  may provides a system that forming a continuous water and moisture retarding barrier along the sides of a rough window or door opening.  
      If desired, additional sealing members  80 ,  82 , may be positioned along periphery  29   b  on the opposing sides of corner flashing members  40  so as to extend in the direction opposite sealing member  78 . Sealing members  80 ,  82 , may be positioned so as to overlap interior flashing portion  42  and membrane flashing portion  46  of corner flashing members  40  as depicted in  FIG. 7 . With corner flashing members  40  and sealing members  78 ,  80 ,  82 , in place, window  68  may be secured in rough opening  24  to complete the installation as depicted in  FIG. 8 .  
      Sealing members  78 ,  80 ,  82 , may be formed from any sealing tape or sealing material suitable for the purpose. Preferably, the sealing tape is a conventional pre-creased, but otherwise generally non-flexible tape such as Tyvek® StraightFlash™ made by E.I. DuPont de Nemours and Company of Wilmington, Deleware. Alternatively, while a more expensive option, flexible tape such as FlexWrap™ by E.I. DuPont could be used. It will also be understood that any kind of flat flashing tape could be used and a crease could be effected in the flat tape as part of the step of applying the sealing members.  
      The thin wall structure of corner flashing member  40  may insure that corner flashing member  40  does not interfere with the installation of a window or door in rough opening  24 , or otherwise require a change in the window or door manufacturer&#39;s specifications for rough opening  24  or specified installation procedure for the door or window. In addition, corner flashing member  40  does not require the use of nails, screws or other fasteners that would penetrate corner flashing member  40  and create a potential avenue for water to enter the interior or cavity of the wall.  
      Although the present invention has been described in terms of the preferred embodiment, it will be understood that variation and changes can be made to the preferred embodiment and that the scope of the invention is set forth in the claims.