I am using a flannel layer cake and will be adding flannel yardage for borders plus flannel yardage for the backing. I have not washed/dried anything yet. Should the first wash be when it's completely quilted and done or would you at least wash/dry the flannel backing before quilting?

I always wash flannel once, unless its for a raggy quilt, then I wait til after. Never had an issue except for some cheap stuff I bought at the chain store and wont do that again.

In your situation Sandy, I would wait to wash til the top is done, before you layer/quilt it. I would wash the backing as well before you layer/quilt it.

It is typically not a good idea to wash precuts of any kind because they can shrink and distort, making them difficult. Flannel shrinks and distorts even more than regular quilting cottons. You could prewash the flannel yardage but, since the precuts won't be washed, you don't really need to. See my previous post about how batting controls the amount that fabric can shrink once the layers are quilted; you simply need at least a moderate amount of quilting to keep the batting in control.

I would warn against washing the top before it is quilted. You can end up with a distorted mess from pieces of fabric shrinking at different rates and in different directions. Also, flannel ravels more than regular quilting cotton (which is why some quilters use 1/2" seams with flannel). You could end up with a *lot* of threads on the wrong side. If a top absolutely has to be washed before being quilted, the safest way to do it is to first closely baste the top to a piece of muslin or other fabric, then hand wash and lay flat to dry. I would not recommend even that for a flannel top because of flannel's horrendous tendency to shrink.

I have washed some flannels that did not shrink at all, and others that still shrank after their 3rd trip through the washer and dryer. There is no way to tell which kinds you will have in your quilt top. This is why it is much safer to quilt before washing so the batting will take over and shrink everything evenly. Fabric shrinks entirely differently when it is washed and dried on its own compared to when it is quilted to a batting and backing.

Also I am aware now that you should use 1/2" seam instead of 1/4 or the seam pulls apart.

I usually wash flannels a couple of times, but it's as much for lint control as the shrinkage. I am not a pre-washer under most circumstances. Flannel is an exception.

So far I only use the for rag quilts but do wash them once. If I had a quilt with other fabrics mixed in I'd probably do it more but with all flannels, and most coming from the same source I only wash once because I know they'll shrink. My rag quilts turn out great so its working so far. I'd definitely do it more if I was using it as backing for cotton, the cotton would get washed as well.

I bought flannel to make pj pants. I'll pre-wash it. Would I be ok to serge the seams or should I use a 1/2 inch seam as you would if piecing a quilt top?

I am so happy that I read your reply to asabrinao's question as I am just finishing up a quilt with a flannel back. I did not prewash any of the fabrics. This has been a real challenge as it is very heavy (Hobbs 80/20) and stiff. I plan to launder it when I am finished. I pray that it will look okay. Yolanda Wood River

Wonder who makes the best flannel??