A common problem that occurs with brick, block and stone is the crumbling away of old mortar. Water can and will enter those loose mortar areas and cause the wall to deteriorate. Tuck- pointing or re-pointing the affected areas helps preserve the integrity of the walls and also improves the looks of the structure. It is also important to seal the areas after the work is done. A stone basement or concrete block basement can be painted after the tuck-pointing is finished.