The Arctic Tern Wildlands door doesn't have a maximum wall thickness specification, but anything thicker than 35.5mm (1.4") may require notching of your wall to allow for clearance of the upper and lower deadbolt mechanisms. You may not be able to mount the included cosmetic latch covers. The flange of the door that extends inward 35.5mm (1.4"), it anything thicker than that measurement will result in an exposed wall core or framing. A custom cosmetic piece may be required to cover the wall core. With thicker walls, the included upper and lower security brackets could not be used, but longer brackets could be fabricated out of angle aluminum.