Deteriorated mortar joints in existing masonry can be cleaned out and refilled with fresh mortar. The procedure, called tuckpointing or repointing, is one of the most common maintenance procedures performed on masonry structures. RAKING THE OLD MORTAR JOINTS Mortar joints should be raked to at least 1/2 inch. Raking refers to removing or cutting out the old mortar. Mortar can be removed with a hand-held grinder, a small mason's chisel, or a special raking tool. CHOOSING A TUCKPOINTING MORTAR Tuckpointing mortar should closely match the existing mortar in strength, hardness, color, and texture. A good first step is to test the existing mortar to see what mix proportions were used. By mixing similar ingredients in the same proportions you can produce a new mortar close in strength to the old mortar. The Brick Institute of America (BIA) recommends Type N or O mortar if the original mortar can't be duplicated. Mortar for tuckpointing should be somewhat drier than mortar used to lay masonry units. FILLING THE JOINTS To ensure good bond with brick masonry, wet the cleaned joints just before applying the mortar, just enough to dampen the surface. The best tools to use for filling the joints are a hawk and a tuckpointer's trowel.