Measure the windows that let in the most light to calculate how much fabric you'll need. Start at the inside top of the valance or window sill, down to about 1 inch below the edge of the window frame. Horizontal measurements should start at the outer corner of the window and extend at least 2 inches wider than the window frame.
Calculate the total yardage you'll need to cover all windows, doubling the amount you need because you will be using two pieces of fabric for each window. Assess the feet required for the hook and loop fastener strips that will attach your fabric coverings to the top of your RV windows, by measuring across the top of every window.
Iron all wrinkles out of the fabric. With the back side of the fabric facing you, iron a 1-inch hem on each piece by folding over all four sides toward you, and ironing the crease. Use Liquid Stitch fabric glue to finish these edges.
Attach two pieces of finished fabric together for each window, by placing one piece on a table in front of you, with the back side facing up. Apply glue all the way around the edges, and mount the second piece of fabric on top, back side down. Use your hand to smooth out any raised spots of glue. Let dry at least an hour.
Cut the fuzzy hook strip to fit the top of each curtain, then adhere it to the top of your finished curtains using Liquid Stitch. Let dry at least an hour.
Adhere the hard, loop strip of fastening tape to the inside edge of the RV window valances or just above the windowsill, and let dry at least an hour.
Check to ensure that all hook and loop adhesive tape strips are securely glued to the valance or window sill. Then, you can darken the RV interior by attaching one curtain to each window. The coverings can be removed when you want to let light inside again.
