This chapter discusses the effects of new reinforcing strategies involving horizontal mortar joints of masonry columns in compression. It presents the results of an experimental investigation on 42 solid clay brick columns internally strengthened by Fiber Reinforced Plastic (FRP) fabrics or stainless steel grids placed in the horizontal joints of mortar. Both FRP fabrics and steel grids are made of materials controlled in the strength and in the geometry and had positive bidirectional effect because have the same number of wires in x and y directions. Carbon FRP were constituted by wire mesh with equivalent thickness 0.165 mm with an internal side of 6 mm and the fibers had depth 4 mm. The experimental program consisted of 42 compressive tests on clay brick masonry columns under concentric and eccentric loads. A criterion is proposed for determination of the compressive strength of a confined column, taking into account the tensile contribution of the internal reinforcements.