Lay the fabric on a flat, smooth surface, right side down.
Cut a rectangle 16 inches long and 8 inches wide.
Cut a circle with a 5-inch diameter.
Stitch the lengthwise sides of the rectangle together with a 1/2 inch seam allowance to make a tube.
Stitch the circle to one opening of the tube with a 1/2 inch seam allowance.
Fold the top of the other end of the tube over 3/4 inch and stitch down. Leave an opening at the seam.
Cut 16 inches of cord. If it is nylon cord, burn the ends to prevent it from unraveling.
Put a safety pin on one end of the cord and use it to thread the cord through the drawstring channel you just made.
Tie the ends of the cord together.
Fill the icemelt sock with calcium chloride de-icer.
Put it on your roof, lying vertically across the ice dam.