Abstract: A universal tile installation mat is described for use in the construction of tiled floors and walls and wherein the mat is secured on a sub-floor surface formed of wood or concrete or a wall surface. The tile installation mat uncouples the mortar and the tiles set therein and disposed over the mat to prevent cracking of the mortar, the tiles and the grouted joints due to displacements in the support surfaces. The tile installation mat is formed from flexible plastics materials and has three different types of support formations integrally formed therein to anchor mortar and to retain heating wires captive in different patterns as desired to form a heated tiled floor or wall. The support formations facilitates ease of installation of heated wires and provides counter acting forces against a heating wire from escaping from anchoring passages formed by the support formations.