A removable rug lining is ideal for quilted rugs as you can wash and dry them separately without risk of melting the liner materials and to avoid uneven shrinkage. You can simply cut a rectangle from the rug pad and place the liner under your rug. If you wish, you can attach the corners of the lining to the rug for extra security using adhesive hook and loop tape.
It can become costly if you need a long rug pad, as these pads are sold in a variety of shapes, but not necessarily the exact shape you need. When I was looking for options to add a 14′ long lining to The Pawesome Floor Runner, I realized that it’s much cheaper to find a shorter rug pad and then re-shape it as needed with a little bit of sewing.
So I purchased a 5′ X 7′ Non-Slip Rug Pad Gripper, then I cut it in half lengthwise to get two 2.5′ X 7′ pieces. Using leftovers of bias binding, I joined these 2 pieces across the short sides into a 2.5′ X 14′ shape (see video below).
NOTE: You may want to use a walking foot for sewing as it’s difficult to stitch through the grip. This video is sped up, but I actually sewed slowly using a regular foot, and forcing the fabric with my hands to move through the feed dogs. You will only have 2 seams that hold 2 pieces of the lining together (1 on each side of the folded fabric strip).