Window sill flashing
The present invention is directed towards a window sill flashing comprising a base having a substantially rectangular shape. A front flange projects perpendicularly downward from a front edge of the base and at least one side flange extends vertically from a side edge of the base. The side flange includes a front surface. The window sill flashing is made from a rigid homopolymer vinyl film.
This application claims the benefit of U.S. Provisional Application No. 60/487,343, filed Jul. 15, 2003, the entire contents of which are herein incorporated by reference.
TECHNICAL FIELDThe present invention generally relates to building materials and more particularly relates to window sill flashing for a window frame to prevent the ingress of water.
BACKGROUND OF THE INVENTIONTypical wall construction techniques include forming a rough opening from framing members such that a window opening is formed. The bottom portion of the window opening (called the sill) is susceptible to rotting if water is not prevented from penetrating from around the window perimeter. Additionally, adjacent ceilings, plastered walls, and the like are susceptible to damage if rain-water infiltrates under the window sill.
Many systems are used to solve the problem of water intrusion. One method includes providing a means to collect and control the water that does infiltrate the window perimeter. Alternatively, surface sealing agents, such as caulk, expanding foam, and the like are used as filling agents to fill openings between the periphery of the window and the adjacent, wall surfaces. However, over time, the filling agents have a tendency to dry, crack and shrink, thereby exposing gaps which provide a passageway for water to infiltrate the window perimeter.
SUMMARY OF THE INVENTIONThe present invention is directed towards a window sill flashing comprising a base having a substantially rectangular shape. A front flange projects perpendicularly downward from a front edge of the base and at least one side flange extends vertically from a side edge of the base. The side flange includes a front surface. The window sill flashing is made from a vacuum formed, rigid homopolymer vinyl film.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to
The flashing 10 of the present invention is preferably manufactured from sheets of thermoforming film, such as a rigid homopolymer vinyl film, or polyvinyl chloride (PVC), or the like. The preferable material properties for flashing 10 are listed in the table below:
It can be appreciated that the flashing 10 may be covered with a silicone coating for ease of manufacturing and separation of the flashing 10 and for ease in installation of window assembly 13.
Flashing 10 is preferably fabricated using vacuum forming techniques. Vacuum forming flashing 10 from thin gage material allows the first and second side flanges 18, 20 to be substantially perpendicular to base 16. The material properties, including the material thickness, provides flexibility to flashing 10, thus allowing the vacuum forming dies to separate from the flashing 10 once the vacuum forming process is completed. Additionally, vacuum forming flashing 10 allows the material to have a minimum thickness (as thin as 7.5 mm). Therefore, when portions of flashing 10 overlap, the resultant gap under the flashing 10 is minimal and does not allow water intrusions.
Due to the geometry and thinness of flashing 10, flashing 10 cannot be manufactured using an injection molding process. If flashing 10 were to be manufactured by injection molding, the minimum thickness feasible for flashing 10 is 40 mm, significantly higher than the practical thickness of flashing 10 formed by the vacuum forming process. Moreover, to maintain the perpendicularity of surfaces 16, 18, 20 and 22 over the depth of base 16, flashing 10 would require ribs, or support struts, to be molded into base 16. These ribs would detract from the functionality of flashing 10. Furthermore, it would be necessary to include ports along base 16 to ensure that sufficient material flows across and covers the entire base 16. These ports would give rise to dimples, or other imperfections in the surface of base 16. The imperfections could create gaps or openings along the window sill, thereby comprising the water impermeability of flashing 10. Even with the use of ports along base 16, obtaining complete flow coverage of injected material is problematic because the preferred depth of base 16 is in the range of 1 inches to 3¼ inches.
The embodiments disclosed herein have been discussed for the purpose of familiarizing the reader with novel aspects of the invention. Although preferred embodiments of the invention have been shown and described, many changes, modifications and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of the invention as described in the following claims.
Claims
1. A window sill flashing, comprising:
- a base having a substantially rectangular shape;
- a front flange projecting perpendicularly downward from a front edge of said base;
- at least one side flange extending vertically from a side edge of said base, said at least one side flange including a front surface; and
- wherein said window sill flashing made from a sheet of rigid homopolymer vinyl.
2. A window sill flashing according to claim 1, further including a rear, vertical rising wall projecting perpendicularly upward from a rear edge of said base.
3. A window sill flashing according to claim 2, wherein said rear, vertical rising wall is located opposite said front flange.
4. A window sill flashing according to claim 1, wherein said rigid homopolymer vinyl is a polyvinyl chloride.
5. A window sill flashing according to claim 1, wherein said rigid homopolymer vinyl sheet has a gauge range between 7.5 to 35 millimeters.
6. A window sill flashing according to claim 1, further including a silicone coating over said window sill flashing.
7. A window sill flashing according to claim 1, wherein said rigid homopolymer vinyl sheet used to fabricate said window sill flashing is supplied from rolled sheet stock.
8. A window sill flashing according to claim 1, wherein said base is devoid of imperfections.
9. A method of installing a window sill flashing along a bottom portion of a window opening, said method comprising:
- exposing said bottom portion of said window opening;
- placing at least one window sill flashing along said bottom portion of said window opening;
- securing said window sill flashing to said bottom portion of said window opening.
10. A method according to claim 9, wherein said exposing said bottom portion of said window opening includes cutting away a cover on said window opening.
11. A method according to claim 9, wherein said securing said window sill flashing to said bottom portion of said window opening includes applying adhesive tape to said window sill flashing.
12. A method according to claim 9, wherein at least two window sill flashings are placed along said bottom portion of said window opening.
13. A method according to claim 9, wherein one window sill flashing is placed along said bottom portion of said window opening.
14. A method according to claim 9, further including cutting said at least one window sill flashing to a predetermined length.
Type: Application
Filed: Jun 18, 2004
Publication Date: Feb 17, 2005
Inventors: Robert Broad (Ypsilanti, MI), Jay McDonald (White Lake, MI)
Application Number: 10/871,401