As with all the previous discussions, the installation of a new tile surface over a laminate countertop or even a backsplash is totally based upon the stability and integrity of the existing material. I would recommend that, if an existing countertop is to be tiled over, the perimeter laminate be covered with a special tile shape, which is specifically manufactured to be used on the edge of a tile countertop. It will be extremely difficult to ensure that a tile edge will remain stable and secure, if the proper tile edge shape is not used. This is the same situation when tiling a backsplash that has an existing laminate surface. Special cove pieces of tile, should be purchased, and used for the interface between the horizontal countertop and the vertical backsplash. It is important to understand that tile is rigid and unforgiving. Therefore any surface that it is applied to, must be consistent and supportive, without spaces or inconsistencies in the surface.
Remember, all the same requirements ensuring that the bonding of the existing surface, and the new tile installation remain. A special primer, bonding agent or thin set, that is specifically manufactured to promote a proper adhesion between the existing sub-base (whatever it maybe) and the new tile installation is required. Manufacturers have developed through research, very bondable materials that are consistent with the application of new surfaces on existing. It is important that anyone performing this type of installation is aware of all the new and improved products that will allow the proper installation of tile, stone, brick over existing surfaces.