Sill pan

1. A method for forming a sill pan, said method comprising:

measuring a width and length of an opening sill to be sealed;

cutting a rectangular piece of flexible sill pan material based on the measured opening sill, said sill pan material having a first surface, a second surface opposite to the first surface, an inner edge, an outer edge, and a pair of side edges, where the inner edge and the outer edge are parallel to each other and perpendicular to the side edges of the flexible sill pan material;

creating a set of fold lines in said rectangular piece of flexible sill pan material to define a back dam along the inner edge, a downward flap along the outer edge, and a seat between said back dam and said downward flap of the sill pan;

placing said seat on the sill;

vertically supporting said back dam with a metal angle; and

placing a toe bead of sealant at a fold line between said seat and said back dam

wherein creating said set of fold lines comprises: creating a first fold line on said first surface that defines a height of said back dam at a first distance measured from the inner edge;

creating a set of two second fold lines on said first surf ace that are perpendicular to said first fold line and are parallel to said side edges at a second distance measured from both of said side edges; and

creating a third fold line on said first surface parallel to said first fold line at a third distance as measured from the outer edge that defines a width of said seat of said sill pan for seating a window frame, and said downward flap.

2. The method of claim 1 wherein said second surface of said flexible sill pan material is waffled or dimpled.

3. The method of claim 1 wherein said flexible sill pan material is an aluminum membrane.

4. The method of claim 1 wherein said flexible sill pan material comprises a butyl backed adhesive.

5. A method for forming a sill pan, said method comprising:

measuring a width and length of an opening sill to be sealed;

cutting a rectangular piece of flexible sill pan material based on the measured opening sill, said sill pan material having a first surface, a second surface opposite to the first surface, an inner edge, an outer edge, and a pair of side edges, where the inner edge and the outer edge are parallel to each other and perpendicular to the side edges of the flexible sill pan material, and where the second surface of said flexible sill pan material is waffled or dimpled;

creating a set of fold lines in said rectangular piece of flexible sill pan material to define the sill pan, wherein creating said set of fold lines comprises creating a first fold line on said first surface that defines a height of a back dam at a first distance measured from the inner edge, creating a set of two second fold lines on said first surface that are perpendicular to said first fold line and are parallel to said side edges at a second distance measured from both of said side edges, and creating a third fold line on said first surface parallel to said first fold line at a third distance as measured from the outer edge that defines a width of a seat of said sill pan for seating a window frame, and a downward flap;

cutting said set of two second fold lines that extend from the outer edge until the third fold line; and

cutting said first fold line from opposing sides from said side edges until said second fold lines to form opposing ends.

6. The method of claim 5 further comprising:

folding said first fold line upward to create the back dam that is perpendicular to said seat; and

folding said set of two second fold lines upward to form two side flaps and end dams that are perpendicular to said seat.

7. The method of claim 6 further comprising:

bending said side flaps outward and perpendicular to said end dams; and

bending said opposing ends upward to seal against said end dams.