This style has a separate soaker pad and base that are sewn together after construction. You could also do something like a velcro-on removable pad with this construction method. That seems like too much of a pain to me though. ;)
For the soaker pad, I used easy to find fabrics this time. Wicking jersey stay-dry top (Joann Fabrics has it). 1 layer of cotton terry cloth. 2 layers of white flannel. This is a fairly heavy soaker pad.
Fabrics pinned together with the outsides facing in:
Now for your backing... This time I used antipill fleece and pink PUL.
The two parts pinned and ready to sew:
Sew around your backing pieces leaving just a turning hole:
Turn through your hole and top-stitch:
Sew or serge around your soaker fabrics leaving just a turning hole:
Turn through your hole:
Close up the hole with your top-stitching and add your wet-zone stitching:
Sew your soaker pad onto your backing with a fairly large zig-zag stitch over the edge:
View of the underside (excuse the dirty donated PUL):
Snaps applied top view:
Wings snapped together:
Pad folded up and snapped closed:
Templates can be downloaded here: http://prefold2fitted.blogspot.com/2012/10/online-free-downloads.html