Abstract:
Bendable ‘Z’ Head flashing is used in conjunction with other building materials above arched openings or components in the exterior walls of buildings to protect the building structure from water intrusion. Pre-formed notches in the vertically mounting flange allow the horizontal portion of the flashing to conform to arched or curved openings, the head of arch top window or door frames, and arched trim.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS AND DISCOSURES 
       [0001]    This non-provisional utility patent application claims the benefit of provisional patent application No. 60/756,646 filed Jan, 6, 2006, and disclosure document number 545447. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to architectural stock flashing material used for weatherproofing the head of arch top windows and doors, and arched trim on the exterior buildings in building construction. 
         [0003]    In construction it is customary to install head flashing at the tops of openings in exterior walls, during the installation of windows, doors, and adjacent siding and trim. Uniform building codes require exterior openings exposed to the weather shall be flashed in such a manner to make them weatherproof. The intent is to keep moisture on the surface of building paper from wetting structural elements or entering the exterior wall cavity. Various flexible flashings, water resistant papers and sealants are utilized to seal around openings, windows or doors onto the building framing and sheathing at the building paper or primary moisture resistance surface, which is then covered by siding and trim. When a window or door has a integral nailing fin for fastening the assembly onto the building framing, flexible sheet flashing employed at the head of an opening can satisfy the building code requirement for protecting the building structure, although additional flashing can be used to provide protection to adjacent exterior siding and trim, as well as increase the weather resistance of the structure. 
         [0004]    Where a window or door does not have an integral nail fin, specific architectural sheet stock called ‘Z’ flashing is commonly used to divert water from the surface of building paper to the outside, away from the head of the opening. This type of flashing is readily available commercially in straight lengths and in various dimensions. The ‘Z’ adjective indicates the three leg configuration of this flashing, with the legs characteristically at right angles to each other. ‘Z’ flashing has also been used in addition to flexible flashing to provide extra protection to the opening and exterior wall components. Historically ‘Z’ flashing is formed from metal. More recent, flashing has been manufactured from plastics. 
         [0005]    With arched or curved top doors and windows, or curved siding trim, ‘Z’ flashing does not easily conform to a radius, with the legs or flanges perpendicular to the curved surface resistant to bending because of the inherent geometry. Because of the resistance to bending, the installation of head flashing along curved surfaces is difficult, if attempted at all. Some sheet metal fabricators have the capacity to custom rolled “Z’ flashing to the exact radius required, which is costly and requires planning ahead. One window manufacture provides arched top windows with an aluminum head flashing preformed to match the window head radius, to be installed directly onto the window head frame. Flashing between siding and wood trim installed above a window with this manufacturer supplied flashing would be a custom fabrication with a different radius and length. For most installations of arched top windows, doors and curved trim there is not a satisfactory solution. 
         [0006]    Construction contractors or trades people have modified commercially available metal or vinyl ‘Z’ flashing in the field by cutting multiple slits into the vertical back leg or mounting flange of ‘Z’ flashing to allow bending, impairing the water diversion capability. It is also inefficient and difficult for field tradespersons to make closed end cuts of uniform length or spacing. Poorly made cuts tend to further lengthen along the cut or induce cracking in the flashing flange, while inaccurately spaced cuts do not permit a uniform radius. With field modified metal flashing, bending can also result in kinking or distortion in legs of the flashing. Flashing with numerous slits is sometimes repaired in the field with a covering of a self-adhering flexible sheet flashing. When a repair is made it can be labor intensive and ineffective. Slits made into the total height of the flashing back leg are difficult to properly repair with flexible sheet flashing, as the sheet material must be carefully placed into the curving corner formed between the back vertical leg and horizontal leg of the flashing, and there is insufficient lap distance between the self-adhering flexible sheet flashing and the notch made in the underlying ‘Z’ flashing. 
         [0007]    For the reasons stated above, it would be very desirable to provide a bendable ‘Z’ flashing for weatherproofing the head of arch top windows, arched door heads, and arched trim. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is an elongate vinyl plastic ‘Z’ flashing comprised of three legs, the larger back vertical attachment flange includes pre-formed notches which allow the other horizontal leg to conform to the arched radius surface of other building construction elements, such as arched head windows and doors, and arched trim. 
         [0009]    In accordance with the invention, the bendable ‘Z’ head flashing is shaped with a flat vertical notched attachment flange, an outwardly projecting horizontal section from the bottom of the flat vertical attachment flange, and a smaller vertical drip edge section projecting downward from the outside edge of the horizontal section. The back vertical flange is installed against building sheathing or adjacent self-adhering window or door flashing. The horizontal section sits on top of a arched window or door frame, or arched trim. The smaller vertical drip edge extends down over the face of the underlying arched building component. 
         [0010]    For the length of the bendable ‘Z’ head flashing, the back vertical mounting flange has equal spaced holes near the top free edge for fastener locations, and equal spaced notches extending from the free edge towards the horizontal section. Each notch terminates in a circular void in proximity to the horizontal section, but at a distance to provide a small section of uninterrupted vertical flange adjacent to the horizontal flange. The diameter of the circular void is larger than the width of the notch, to distribute tension stresses at the base of the flat vertical mounting flange over a larger circle circumference and reduce the possibility of cracking and buckling. 
         [0011]    When the flashing is curved during installation, the notches will widen adjacent to the upper free edge of the vertical mounting flange, and the circular voids will deform to an oval shape. Because of the flexible composition, the horizontal portion or leg of the present invention can readily conform to a radius, and small effective dimensional areas of both vertical flanges can absorb tension and compression stress without undo deformation. 
         [0012]    The present invention is installed in sequence with the building wall moisture barrier, arched doors, windows or adjacent arched trim, before installing exterior siding. Building structural framing, siding and trim around windows and doors is protected from rainwater or other moisture by bendable ‘Z’ head flashing in conjunction with other building materials. Bendable ‘Z’ head flashing protects the joint between dissimilar construction components and directs moisture outward away from building moisture barriers. 
     
    
     
       BRIEF DESRIPTION OF THE DRAWINGS 
         [0013]    The present invention can be utilized in many ways. The following descriptions and graphic indications represent potential uses of the invention to characterize the idea and general usefulness, and are not intended to limit the invention to that described or depicted herein. Notation numbers used within the FIGS. correspond to the same features or components throughout the drawings. 
           [0014]    Referring to the views contained on drawings sheets 1 through 6: 
           [0015]      FIG. 1  shows an oblique view of a portion of bendable ‘Z’ head flashing. 
           [0016]      FIG. 2  is a cross section view of the bendable ‘Z’ head flashing taken along  2 - 2  in  FIG. 1 . 
           [0017]      FIG. 3  is an oblique view of a portion of bendable ‘Z’ head flashing with a smaller horizontal leg. 
           [0018]      FIG. 4  is a cross section view of bendable ‘Z’ head flashing taken along  4 - 4  in  FIG. 3 . 
           [0019]      FIG. 5  is a partial revealed front view of bendable ‘Z’ head flashing installed over a portion of arched top window. 
           [0020]      FIG. 6  is a cross section view of bendable ‘Z’ head flashing installed an arched top window taken along  6 - 6  in  FIG. 5 . 
           [0021]      FIG. 7  is a cross section view of bendable ‘Z’ head flashing installed above arched trim. 
           [0022]      FIG. 8  is a cross section view of bendable ‘Z’ head flashing installed above an arched door or window frame. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]      FIGS. 1-8  illustrate two embodiments of the present invention.  FIGS. 1 and 2  indicate one embodiment, while  FIGS. 3 and 4  show a second embodiment.  FIGS. 5-8  show the bendable ‘Z’ head flashing integrated into different building components. Building components illustrated in  FIGS. 5-8  characterize the use and installation of the present invention, but do not preclude use of bendable ‘Z’ head flashing with other building materials and construction components. 
         [0024]      FIG. 1  is a oblique view of a portion of a novel bendable ‘Z’ head flashing  1 . The rear vertical mounting flange  2  is shown with equally spaced notches  3 . Each notch terminates in a circular void  4 , being in proximity to the horizontal section, but maintaining a distance to provide a small section of uninterrupted vertical flange adjacent to the horizontal flange. When the horizontal leg  6  is curved during installation to conform to a radius, notches  3  will uniformly spread apart along the upper free edge of vertical mounting flange  2 . The diameter of the circular void  4  is larger than the width of the notch, to distribute tension stresses at the end of the notch over a larger circle circumference and reduce the possibility of cracking and buckling. Holes  5  for fasteners used during installation are located between notches. 
         [0025]      FIG. 2  is a cross section view of the bendable ‘Z’ head flashing taken along  2 - 2  in  FIG. 1 . 
         [0026]      FIG. 2 . indicates the horizontal section  6  between the two vertical faces, with which it forms right angles. In this embodiment of the present invention, the preferred dimension of horizontal section  6  is 1⅝ inches to accommodate dimensions of common building components. 
         [0027]    Both  FIGS. 1 and 2  show the thicker bead  8  at the free end of vertical flange  7 . This bead helps resist buckling in the outward vertical flange  7  during curving to a radius. 
         [0028]      FIG. 3  is an oblique view of a portion of a novel bendable ‘Z’ head flashing. This embodiment differs from that shown in  FIGS. 1 and 2  because of a smaller horizontal member  10 . All other features and use remains the same as described in  FIG. 1 . 
         [0029]      FIG. 4  is a cross section view of bendable ‘Z’ head flashing taken along  4 - 4  in  FIG. 3 . In this view the preferred dimension of horizontal leg  10  is ⅞ths of an inch, to accommodate and match the dimension of common building components. 
         [0030]      FIG. 5  is a partial revealed front view of bendable ‘Z’ head flashing  1  installed over a portion of an arched top window  14 . In sequence of preferred installation, the window  14  with a nail fin is installed onto an frame arched opening in the exterior building sheathing  12 . Building paper  18  is completed up to the spring point of the opening, awaiting completion of the following installation steps for construction component sequencing. The window nail fin is flashed to the surface of  12  with a self-adhering flexible flashing  16 . After cutting to the proper length of the arc, the flexible ‘Z’ head flashing  1  is then fitted, with horizontal leg  6  resting on top of a projecting portion of the arch top window  14 , vertical mounting flange  2  set on top of self-adhering flexible flashing  16 , and vertical leg  7  covering the corner of window  14 . The flashing  1  is held in place at the desired curve with fasteners driven through numerous mounting holes  5  into exterior building sheathing  12 . 
         [0031]      FIG. 5  also indicates as a result of the radius in horizontal member  6 , notches  3  in mounting flange  2  have spread apart. The extent of spreading with vary with the installed radius. Athough the ends of notches stop at holes  4  a distance above the horizontal flange, additional self-adhering flexible flashing  17  is then installed over the rear mounting flange  2 , extending past the jamb of window  14  onto adjacent building paper. The self-adhering flexible flashing  17  and the remainder of the adjacent wall  12  is then covered with building paper  18 . The building paper is covered with siding  19 . A gap  20  is left between siding  19  and the horizontal leg  6 . This gap is filled with sealant at the ends of the flexible ‘Z’ head flashing  1 . 
         [0032]      FIG. 6  is a cross section view of bendable ‘Z’ head flashing  1  installed over an arched top window or door taken along  6 - 6  in  FIG. 5 . Window  14  includes a nail fin for mounting, which is also flashed with self-adhering membrane  16 . Siding  19  is indicated here as lap siding, but the type used does not effect the installation of the present invention. In bendable ‘Z’ flashing  1 , the horizontal leg  6  extends out past the face of arched top window or door  14 . The exact projection distance will vary with window and door manufactures, with most units accommodated within flashing  1 . Where the arched frame portion of the window or door  14  does not extend as far, bendable ‘Z’ head flashing  9  indicated in  FIGS. 3 and 4  may be used instead of bendable ‘Z’ head flashing  1 . 
         [0033]      FIG. 7  is a cross section view of bendable ‘Z’ head flashing  1  installed over arched trim  15 . The arched trim follows the arch radius at its lower surface, with the upper surface radius increased by the height of the trim. Window  14  includes a nail fin for mounting, which is flashed with self-adhering membrane  16 . Siding  19  is graphically shown as lap siding, but the type used can vary and does not effect the installation of the present invention. In bendable ‘Z’ flashing  1 , the horizontal leg  6  extends out past the face of trim. The dimension of horizontal leg  6  has been sized to fit this common trim size. The vertical mounting flange  2  and adjacent construction materials would appear similar to that shown in FIG,  5 . Moisture or rainwater that originates above this head flashing  1  within siding or trim joints will run down the surface of the building paper until reaching the radius surface of the head flashing. Although the gap between siding and leg  6  allows moisture to exit from behind the siding, moisture will run along the radius towards the ends of the flashing. This gap  20  is to be filled with sealant at the flashing ends above window or door jamb trim. The joint  21  between window and trim is filled with sealant. 
         [0034]      FIG. 8  is a cross section view of bendable ‘Z’ head flashing  9  installed over arched trim  15 . The arched trim follows the arch radius of a window or door at its lower surface, with the upper surface radius increased by the height of the trim. The arched frame  22  does not include a nail fin, typical of a wood or composite frame window or entry door. In this view building paper  18  is shown extending downward from behind the back mounting flange  2  of bendable ‘Z’ flashing  9 , although other flashing materials can be used, as recommended by the door manufacturer. The horizontal leg  10  of the bendable ‘Z’ flashing sits on top of the arched trim  15 . The dimension of horizontal leg  10  has been sized to fit the common trim size indicated. The flashing  9  and adjacent construction materials would appear similar to that shown in front view  FIG. 5 . Moisture or rainwater that originates above this opening head within siding or trim joints will run down the surface of the building paper until reaching the radius surface leg  10  of the head flashing  9 . The gap  20  between siding  19  and leg  10  must be filled with sealant at the flashing ends above window or door jamb trim. 
         [0035]    Useful embodiments of the invention have been described and illustrated, including depictions of building components necessary to integrate the invention with various surrounding building materials. It is understood that the words used are descriptions rather than limitations, and the present invention is not limited to the embodiments described above, but encompass any and all embodiments within the scope of the following claims.