Window and Door Sill Pan Flashing
1) Cut house-wrap in a "t and v" fashion ( the top part of the opening is cut like a "t" and the bottom half of the opening is cut like an upside down "v" )
2) Fold the house wrap into the opening and trim it off even with the inside face of the wall opening.
The RO needs to be a minumum of 1/2 inch wider that the fenestration unit. Each corner will need approx. 3/16 inch of space (3/8 inch for the two). Make sure that there is no trash or protruding nails on the sill, jamb or the face of the wall sheathing so that the part install nicely into the corner. Hold pan corner firmly in RO. Mark point with knife above nail slot. Remove pan and cut house wrap into the opening.
Lift the house wrap. Place the pan underneath. Fold wrap back down. Water will now flow over and into the pan without taping. Repeat for the other side.
Cut the straights to fit. Score several times and snap the cut straights to fit. Cut away from yourself. Score several times and snap it easily apart.
Apply waterproof tape over joints. Holding the tape up at the back, start at the front edge and work the tape toward the back dam. ( 2-inch butyl foil-backed tape works great for this )
Make and use a taping tool from a piece of scrap pan material. Hold tape off of the back dam, work the tape into the inside corner. *Use tool for this, not your fingers*
Once tape is securely into the inside corner, tape over the back dam and then finish up with your fingers.
If you keep the tape off of the house wrap the pan can rise with the window / door during shimming. Remember to nail the pan loosely in the nail slots to allow it to move up during shimming.
For larger openings just add more straight sections.
IT IS THAT SIMPLE!