I just washed 5 yards of 108" backing with no problems. I set the machine on low agitation with a short wash cycle so it does not tie it into a big knot.
I did have my husband help fold it - and we had to go across the hall and use both rooms to get far enough away from each other to stretch it out.
When I did the batik shirts, I cut each bolt in half -so about 8 yards of 45" fabric.
BTW - If I toss a large cotton sheet in the dryer, dry on med/low heat, run the cool down cycle and remove and fold promptly, I have not need to iron the fabric.
If I leave the towel out - most often I have a wrinkly mess when I take it out of the dryer. I've even rewashed a time or two because I forgot the towel and didn't want iron.