Here is a mock up using wood of a K-Hinge with a zipper sewn in. This is the closed position. This allows the hinged joint to be folded over on itself when unzipped or to stiffen the hinged joint when zipped together. Leaning on this prototype with many pounds of force showed that it held together well. Surely the foam board would have broken with so much stress applied to it. Since the glue and canvas are in shear during the stress test, then only the thread and zipper’s cloth are the only weak spots. You can see the one corner of canvas where I peeled it up to see how well the glue held up. The glue bond is much stronger than the bond that the aluminum foil has to the paper on the foam board.

This is the open or folded position. Leaving a couple of inches of zipper hanging off of the end, makes it easy to start the zipper when assembling the Yurt.

There is the end view of the K-Hinge and the zipper. I’ll try and sew the gap between boards a little tighter when I build the foam board versions.