Architectural and Engineering Glossary


Lead Nail

A nail for fixing a lead sheet to a roof.Such nails are often fabricated of a copper alloy. 

Lead Naphthenate

A liquid drier added to paints containing drying oils to promote rapid drying and hardening.

Lead Paint

Any paint containing white lead.

Lead Pip

Pipe fabricated from 99.7 percent pig lead;various lead alloys are also available for special applications such as drainage.Lead pipes are interconnected by wiped joints,burned joints,or flanged joints.

Lead Pipe Cinch

An easy type of joint used in fabricating pipe from elongated sheets of lead.First,the lead sheets are formed in a cylindrical shape with a flat overlap perpendicular to the cylinder;then,the flat overlap is folded over and crimped,thereby forming a sealed joint.

Lead Plug

1.A small cylinder of lead which is forced into a hole in a masonry wall;serves as a point of attachment for a screw or nail driven into it.2.A piece of lead between adjacent stones, for holding them together;formed by pouring molten lead in a groove cut in the jointing faces.

Lead Primer

See red lead.

Lead Roof

A flat roof covered with sheet lead.

Lead Safe

See drip sink.

Lead Shield

A type of anchor,for an expansion screw or bolt,which consists of a lead sleeve that surrounds it.

Lead Slate, Copper Slate, Lead Sleeve

A cylindrical sleeve,formed of sheet lead or sheet copper,used around a pipe where it penetrates a roof to make the intersection watertight

Lead Sleeve

See lead slate.

Lead Soaker

See soaker.

Lead Spitter

A tapered connector  between a lead gutter and a downpipe.

Lead Tack

1.A lead strip used to secure the free edge of flashing;one end of the tack is fixed to the structure and the other end is folded over the free edge of the sheet metal.2.A rectangularpiece of lead which is attached to a lead pipe and enables it to be secured to a wall or other support.

Lead Wedge

A tapered strip of lead used to secure a flashing to a masonry wall.

Lead Wing

In patent glazing,a strip of lead around a pane of glass to secure it and to prevent the entry of water.

Lead Wool

A wool-like material of fine strands of lead;sometimes used as caulking in pipe joints.

Lead-capped Nail

Same as lead head nail.


cable An electric cable which is provided with a covering of lead to exclude moisture and to provide mechanical protection.

Lead-free Paint

A paint which contains no white lead or similar lead compounds.

Lead-lag Ballast

A ballast for two fluorescent lamps,one of which operates on leading current and the other on lagging current;tends to reduce the stroboscopic effect.

Lead-lined Door, Radiation-retarding Door

A door which is lined internally with lead sheets to prevent the penetration of x-ray radiation.

Lead-lined Frame, Radiation-retarding Frame

A doorframe internally lined with sheet lead to prevent the penetration of x-ray radiation;always used with lead-lined doors.

Lead-sheathed Cable

Same as lead-covered cable.


Same as starter frame.

Leaded Brass

An alloy of copper and zinc to which lead has been added to improve machinability.

Leaded Glass

See leaded light.

Leaded Joint

A plumbing joint that is sealed by pouring hot lead around it.

Leaded Light

A window having small diamond shaped or rectangular panes of glass set in lead cames.

Leaded Zinc Oxide

One of a series of mixed white pigments consisting of zinc oxide and  basic lead sulfate;used principally in exterior house paints.


1.A downspout.2.A duct for conducting hot air to an outlet in a hot-air heating system.

Leader Head, Conductor Head, Rainwater

head An enlargement or catch basin to receive rainwater from the gutter at the top of a leader.


A method of setting small panes of glass in a window with cames fabricated of lead.

Leading Edge, Lock Edge, Strike Edge

The vertical edge of a swinging door or window which is opposite the hinge edge.


Short lengths of electric conductors,usually insulated;usually used in the plural.


1.A hinged part;a separately movable division of a folding or sliding door.2.One of a pair of doors or windows.3.One of the two halves of a cavity wall.

Leaf And Dart,heart And Dart

In Greek architecture and derivatives,a pattern of alternating,conventionalized,deltoid and lanceolate leaves,usually applied to a cyma reversa.

Leaf And Square

A small tool used by plasterers in ornamental work;has a leaf-shaped blade at one end and a rectangular blade at the other.leak  See sound leak.

Lean Clay

A clay having low values of liquid limit and plasticity index.

Lean Concrete

Concrete of low cement content. 

Lean Lime

An impure lime;has lower plasticity than pure lime.

Lean Mix,lean Mixture

1.A concrete or mortar mixture with relatively low cement content.2.A plaster which is not workable.

Lean Mortar

Mortar which is deficient in cementitious components;is sticky and adheres to the trowel;is difficult to spread.


A small extension to a building with a roof (having but one slope) whose supports lean against the building.

Lean-to House

A seldom-used term used for a saltbox house.

Lean-to Roof,half-span Roof

A roof having a single pitch,carried by a wall which is higher than the roof.

Leaning Tower

A tower,usually detached and slender for its height,which overhangs its base;the most famous example of such a tower is at Pisa Italy,where the 179 ft (54.6 m) tower is16.5 ft (5 m) out of perpendicular.

Lear Board,layer Board

A board which is fixed across the rafters to provide a bearing surface for a roof gutter lining.


A contract transferring the right of possession of buildings,property,etc.for a fixed period of time,usually for periodical compensation called rent.