When hinging extra thick multiple layer mats to a mount board, you must allow enough space in the hinge so the mats will lay flat against the mount board.

You may use sheets of matboard as a temporary spacer under the mount board to lift the mount board to the thickness of the multiple mat. (See illustrations below.)

Close the mat with the mount board on the bottom. It is important to protect the top mat from your table top where unnoticed debris and dirt, picked up from the table, may mar the surface of the top mat.