Abstract: A base is provided for the installation of tiled coverings on unprepared underlying substrates and a method for using the base. The base has two substantially parallel surfaces, openings to permit the introduction of mortar between the base and the underlying substrate, fastening points for the use of mechanical fasteners to attach the base to the underlying substrate, and fixed or adjustable spacers to keep the base in proper alignment with the underlying substrate. One or more curved edges may be added to accommodate curved-edged tiled coverings, interlocking segments may be added to provide additional lateral support and a ledge may be added to assist in supporting the tiled coverings or for leveling purposes. Mortar may be introduced into the space between the lower surface of the base and the underlying substrate through openings in the base and the tiled coverings are attached to the mortar presented at the openings.