How to Flash a Vinyl Window

Properly flashing vinyl windows will prevent water from damaging the structure of the house.

After you have installed a vinyl window, and before you apply siding to the house, flashing should be affixed around the window frame. Self-adhesive flashing applied around vinyl windows prevents wind-driven rain water from seeping into the gaps between siding and window frames. Water allowed to soak into the structure of the house can cause serious damage over time. Flashing is cut to fit and installed around all the sides of the mounted window frame. The width of the flashing you use, and the technique with which it is applied will vary depending on the window installed.

Things You'll Need

• Self-adhesive flashing material
• Masking tape
• Paper of plastic sheeting
• Industrial scissors
• Spray adhesive
• J-roller

Instructions

1. Select your flashing material. Consult the manufacturer's instructions regarding the width of the flashing material you should use with the type of window you have installed. Generally flashing is sold in rolls of either 4- or 6-inch thickness.

2. Cut the flashing to size with your industrial scissors. There are different layering techniques depending on the size and type of window you are flashing. Refer to the manufacturer's instructions regarding the technique you should employ for flashing the specific type of window you have installed.

3. Mask the window glass. Cut plastic or paper sheeting to size and mount it over the glass pane with masking tape.

4. Spray the nail fin and building wrap with spray adhesive. You want to cover from the nail fin to the width of your flashing with a layer of adhesive spray.

5. Apply the flashing to the nail fin and over the building wrap. Start with the side pieces. They will extend beyond the top and bottom of the window a distance specified by the window manufacturer. Apply the header and footer strips so that they overlap the ends of the side pieces of flashing.

6. Use your j-roller to smooth the flashing and remove any air bubbles or wrinkles that may have developed during the application process.

References

• Jeld Wen Doors and Windows: Installation Instructions
• HGTV: Peel and Stick Window Flashing