what is your concern? I back most of my quilts with flannel- have for many, many years- I treat it just like any other cotton fabric- load it up, and quilt. you may want to check with the *owner* and find out if she pre-washed the flannel- if you do not know- if it is not pre-washed it shrink when it is finished & laundered- but it depends on the batting used & the amount (density) of the quilting how much it will shrink (and the quality of the flannel/tightness of the weave. but as for quilting --- it is just another cotton fabric- quilts up just fine.