We don't recommend installing it on an uneven surface. Natural cork needs consistent contact with the wall to adhere properly. If the surface has bumps, dips, or other irregularities, a 3mm cork roll may not bond evenly. Over time, sections of the material could start to lift, resulting in an uneven appearance and a less durable finish.
For reliable adhesion, prepare the wall so that it is smooth, level, clean, and free of debris before installation — a properly prepared surface gives 3mm natural cork a solid base to bond to and helps create a clean, professional-looking result.