JACK ARCH - One having horizontal or nearly horizontal upper and lower surfaces. Also called flat or straight arch.
JAMB - The vertical side of a window or door opening, against which the sash or the door abuts.
JOINT - The space between installed units or between dimensional stones and the adjoining material.
JOINT REINFORCEMENT - Steel reinforcement placed in or on mortar bed joints.
JOINTING - The finishing of joints between courses of masonry units before the mortar has hardened.
JOINTING SCHEME - Architectural drawing detailing dimensions, location and configuration of stone units and joints related to the structure.
JOINTS - Flush, rake, cove, weathered, bead, stripped, and "V".
JOIST - A horizontal member in the framing of a floor or ceiling.
JUMPER - In ashlar patterns, a piece of stone of higher rise than adjacent stones which is used to end a horizontal mortar joint at the point where it is set.
KAOLINITE - A hydrous aluminum silicate mineral.
KERF - A slot into the edge of stone with saw blade for insertion of anchors.
KEY BLOCK - In deepening a quarry, or starting to quarry downward from a horizontal surface, the first block removed from a new ledge, providing space and access for further block removal by undercutting, underdrilling, or lateral shifting.
KEYSTONE - The last wedge-shaped stone placed in the crown of an arch regarded as binding the whole.
KILN - A furnace, oven, or heated enclosure used for burning or firing brick or clay material.
KILN RUN - Brick from one kiln that have not yet been sorted or graded for size or color variation.
KING CLOSURE - A brick cut diagonally to have one two-inch end and one full width end.
KNEELER - Gabled cope stone which by its shape is also part of the wall, and may support other cope stones.
LAP - To overlap one surface with another.
LATERAL SUPPORT - Method wherby walls or columns are braced in the vertical span by beams, floors or roofs, or walls in the horizontal span by columns, pilasters, buttresses or cross walls.
LATEX ADDITIVE - Rubber or resins in water which coalesce to form a continuous film that imparts specific properties to portland cement products.
LATHE - Machine for turning columns, balusters, and other circular stone work; also for rubbing and polishing surfaces of same.
LAVA - A general term applied to igneous rocks such as basalt and rhyolite, that erupted from the earth by volcanic action.
LEAD - The section of a wall built up and racked back on successive courses. A line is attached to leads as a guide for constructing a wall between them.
LEAD BUTTONS - Lead spacers in the solid horizontal joints to support the top stones until mortar has been set.
LEDGER - A slab of stone used horizontally to cover a tomb.
LEGS - Vertical dimension stone used on sides of a fireplace opening.
LEWIS BOLT - A tapered head device wedged into a tapered recess in the edge of a dimensional stone unit, used for lifting purposes and hanging soffits.
LEWIS HOLES - Holes in cut stones for lifting and supporting during setting of cut stones and sometimes for permanent support. Holes are checked for the particular Lewis (lifting device or hook) to be used.
LIME PUTTY - Hydrated lime on plastic form ready for addition to mortar.
LIME-Hydrated - Carbon hydroxide or slaked lime that has been reduced to dry powder.
LIME-Hydraulic - Containing compounds which cause a chemical set in reaction with water.
LIMESTONE - A sedimentary rock composed primarily of calcite or dolomite. The varieties of limestone used as dimensional stone are usually well consolidated and exhibit a minimum of graining or bedding direction. Limestones that contain not more than five percent magnesium carbonate may be termed calcite limestone, as distinguished from those that contain between five and forty percent magnesium carbonate, and from those that contain in excess of forty percent as the mineral dolomite. Recrystallized limestones and compact, dense, relatively pure microcrystalline varieties that are capable of taking a polish are known as marbles.
LINE - A string stretched taut as a guide for laying the top edge of a course of masonry units.
LINE PIN - A metal pin used to attach line used for alignment of masonry units.
LINERS - Structurally sound sections of stone that are cemented and dowelled to the back of stone wall units, to give greater strength, additional bearing surface, assist in support, or to increase joint depth.
LINERS - Structurally sound sections of stone cemented and doweled to the back of thin stone units; to give greater strength, additional bearing surface, or to increase joint depth.
LINTEL - A beam placed or constructed over an opening in a wall to carry the superimposed load.
LIPPAGE - A condition where one edge of a stone is higher than adjacent edges, giving the finished surface a ragged appearance.
LIPPING - Usually refers to flagging materials. Lipping is caused when two pieces of material to be joined together are slightly warped or twisted causing one or more edges to be higher or lower than the adjoining material.
LOADBEARING - A structural system or element designed to carry loads in addition to its own dead load.
LUG - A small projecting member of a larger stone piece, to engage an adjoining unit or to serve as an aid in handling.
LUG SILL - Stone sill set into the jambs on each side of masonry opening.
JAMB - The vertical side of a window or door opening, against which the sash or the door abuts.
JOINT - The space between installed units or between dimensional stones and the adjoining material.
JOINT REINFORCEMENT - Steel reinforcement placed in or on mortar bed joints.
JOINTING - The finishing of joints between courses of masonry units before the mortar has hardened.
JOINTING SCHEME - Architectural drawing detailing dimensions, location and configuration of stone units and joints related to the structure.
JOINTS - Flush, rake, cove, weathered, bead, stripped, and "V".
JOIST - A horizontal member in the framing of a floor or ceiling.
JUMPER - In ashlar patterns, a piece of stone of higher rise than adjacent stones which is used to end a horizontal mortar joint at the point where it is set.
KAOLINITE - A hydrous aluminum silicate mineral.
KERF - A slot into the edge of stone with saw blade for insertion of anchors.
KEY BLOCK - In deepening a quarry, or starting to quarry downward from a horizontal surface, the first block removed from a new ledge, providing space and access for further block removal by undercutting, underdrilling, or lateral shifting.
KEYSTONE - The last wedge-shaped stone placed in the crown of an arch regarded as binding the whole.
KILN - A furnace, oven, or heated enclosure used for burning or firing brick or clay material.
KILN RUN - Brick from one kiln that have not yet been sorted or graded for size or color variation.
KING CLOSURE - A brick cut diagonally to have one two-inch end and one full width end.
KNEELER - Gabled cope stone which by its shape is also part of the wall, and may support other cope stones.
LAP - To overlap one surface with another.
LATERAL SUPPORT - Method wherby walls or columns are braced in the vertical span by beams, floors or roofs, or walls in the horizontal span by columns, pilasters, buttresses or cross walls.
LATEX ADDITIVE - Rubber or resins in water which coalesce to form a continuous film that imparts specific properties to portland cement products.
LATHE - Machine for turning columns, balusters, and other circular stone work; also for rubbing and polishing surfaces of same.
LAVA - A general term applied to igneous rocks such as basalt and rhyolite, that erupted from the earth by volcanic action.
LEAD - The section of a wall built up and racked back on successive courses. A line is attached to leads as a guide for constructing a wall between them.
LEAD BUTTONS - Lead spacers in the solid horizontal joints to support the top stones until mortar has been set.
LEDGER - A slab of stone used horizontally to cover a tomb.
LEGS - Vertical dimension stone used on sides of a fireplace opening.
LEWIS BOLT - A tapered head device wedged into a tapered recess in the edge of a dimensional stone unit, used for lifting purposes and hanging soffits.
LEWIS HOLES - Holes in cut stones for lifting and supporting during setting of cut stones and sometimes for permanent support. Holes are checked for the particular Lewis (lifting device or hook) to be used.
LIME PUTTY - Hydrated lime on plastic form ready for addition to mortar.
LIME-Hydrated - Carbon hydroxide or slaked lime that has been reduced to dry powder.
LIME-Hydraulic - Containing compounds which cause a chemical set in reaction with water.
LIMESTONE - A sedimentary rock composed primarily of calcite or dolomite. The varieties of limestone used as dimensional stone are usually well consolidated and exhibit a minimum of graining or bedding direction. Limestones that contain not more than five percent magnesium carbonate may be termed calcite limestone, as distinguished from those that contain between five and forty percent magnesium carbonate, and from those that contain in excess of forty percent as the mineral dolomite. Recrystallized limestones and compact, dense, relatively pure microcrystalline varieties that are capable of taking a polish are known as marbles.
LINE - A string stretched taut as a guide for laying the top edge of a course of masonry units.
LINE PIN - A metal pin used to attach line used for alignment of masonry units.
LINERS - Structurally sound sections of stone that are cemented and dowelled to the back of stone wall units, to give greater strength, additional bearing surface, assist in support, or to increase joint depth.
LINERS - Structurally sound sections of stone cemented and doweled to the back of thin stone units; to give greater strength, additional bearing surface, or to increase joint depth.
LINTEL - A beam placed or constructed over an opening in a wall to carry the superimposed load.
LIPPAGE - A condition where one edge of a stone is higher than adjacent edges, giving the finished surface a ragged appearance.
LIPPING - Usually refers to flagging materials. Lipping is caused when two pieces of material to be joined together are slightly warped or twisted causing one or more edges to be higher or lower than the adjoining material.
LOADBEARING - A structural system or element designed to carry loads in addition to its own dead load.
LUG - A small projecting member of a larger stone piece, to engage an adjoining unit or to serve as an aid in handling.
LUG SILL - Stone sill set into the jambs on each side of masonry opening.