A lot depends on what fabric and pattern you are using for the runner. I did one with bandana fabrics on the front and denim on the back. That one I did not add batting of any kind as I felt like it was ok as it was. Any others I've done I've used a really low loft batting (left over from doing a kid's cloth book). I liked the slight poufiness of the batting on the SID french braid ones I did.