The PlexiDor pet doors are designed to fit the thickness of standard US household doors. If your door is thicker or thinner than the PlexiDor frame adjusts for, there are some easy fixes.
If the household door is too thin, you can make trim pieces from plywood or some other thin wood to make up the difference. Once the PlexiDor is installed, you usually can’t tell the difference.
If the household door is too thick, you need to add trim pieces to the “tunnel” through the door to make up the difference in thickness. Start by using a water barrier tape, like roofing tape, around the edge of the installation hole to make sure water won’t creep in under the trim piece.