Lag Screw or Bolt - Heavy-duty screw with a bolt head for attaching structural members to a wall or to material too thick for a machine bolt to go through.

Laminated Glass - Two or more layers of glass separated by a thin layer of flexible clear plastic which holds the glass in place when it breaks, reducing the risk of injury from flying glass. Laminated annealed glass does not have the impact resistance of tempered glass, so will crack under impact. However it is possible to laminate tempered glass offering the benefits of both types of glass.

Laminated Safety Glass - Two or more layers of tempered glass separated by a thin layer of flexible clear plastic which holds the glass in place when it breaks, reducing the risk of injury from flying glass.

Laminated Shingles - Shingles that have added dimensionality because of extra layers or tabs, giving a shake-like appearance. May also be called "architectural shingles" or "three-dimensional shingles."

Laminating - Bonding together two or more layers of materials.

Landing - A platform between flights of stairs or at the termination of a flight of stairs. Often used when stairs change direction. Normally no less than 3 ft. X 3 ft. square.

Lap - To cover the surface of one shingle or roll with another.

Latch - A beveled metal tongue operated by a spring-loaded knob or lever. The tongue's bevel lets you close the door and engage the locking mechanism, if any, without using a key. Contrasts with dead bolt.

Lath - A building material of narrow wood, metal, gypsum, or insulating board that is fastened to the frame of a building to act as a base for plaster, shingles, or tiles.

Lath and Plaster - The most common wall finish prior to the introduction of drywall. Thin wood strips (lath) were nailed onto the framing as a base for the sand/lime plaster.

Lattice - An open framework of criss-crossed wood or metal strips that form regular, patterned spaces.

Lattice Fencing - Wood fencing, usually cedar, constructed of prefabricated lattice panels.

Lazy Susan - A circular cabinet shelf that revolves and is typically used in a corner kitchen cabinet unit.

Leader - A pipe that is installed to carry storm water from a roof to a storm building drain or sewer.

Ledger Strip - A strip of lumber nailed along the bottom of the side of a girder on which joists rest.

Leech Field - A method used to treat/dispose of sewage in rural areas not accessible to a municipal sewer system. Sewage is permitted to be filtered and eventually discharged into a section of the lot called a leech field.

Left Hand (Door) - Pertaining to an inward swinging door with hinges on the left side, using the outside of the door as reference.

Left Hand (Tub) - When you stand at the side of the tub, the drain is on the left.

Let-in Brace - Nominal 1 inch-thick boards applied into notched studs diagonally. Also, an "L" shaped, long (@ 10') metal strap that are installed by the framer at the rough stage to give support to an exterior wall or wall corner.

Level - True horizontal. Also a tool used to determine level.

Level Payment Mortgage - A mortgage with identical monthly payments over the life of the loan.

Lien - The legal right of a party, such as a subcontractor or a worker or a supplier, to place an encumbrance on the title of a property; that encumbrance will prevent sale or transfer of title without court approval. This obstacle to free title can be used by a court to control the property title or threaten to have it sold for payment of a valid lien claim.

Light - Space in a window sash for a single pane of glass. Also, a pane of glass.

Limit Switch - A safety control that automatically shuts off a furnace if it gets too hot. Most also control blower cycles.

Limiting Distance - The distance from an exposing building face to a property line, the centre line of a street, lane or public thoroughfare, or to an imaginary line between 2 building or fire compartments on the same property, measured at right angles to the exposing building face.

Lineal Foot - A unit of measure for lumber equal to 1 inch thick by 12 inches wide by 12 inches long. Examples: 1" x 12" x 16' = 16 board feet, 2" x 12" x 16' = 32 board feet.

Lintel - A horizontal structural member that supports the load over an opening such as a door or window.

Live Load - The load other than the dead load to be assumed in the design of the structural members of a building. It includes loads resulting from snow, rain, wind, earthquake and those due to occupancy.

Loads - Live load; the total of all moving and variable loads that may be placed upon a building. Dead load; the weight of permanent, stationary construction included in a building.

Load Bearing Wall - Includes all exterior walls and any interior wall that is aligned above a support beam or girder. Normally, any wall that has a double horizontal top plate.

Loan - The amount to be borrowed.

Loan to Value Ratio - The ratio of the loan amount to the property valuation and expressed as a percentage. E.g. if a borrower is seeking a loan of $200,000 on a property worth $400,000 it has a 50% loan to value rate. If the loan were $300,000, the LTV would be 75%. The higher the loan to value, the greater the lender's perceived risk. Loans above normal lending LTV ratios may require additional security.

Lock Set - Complete set of hardware including the lock, knobs, screws, and strikeplate.

Lookout - A short wood bracket or cantilever that supports an overhang portion of a roof.

Lot Line - Line forming the legal boundary of a piece of property; also called property line.

Louver - A vented opening into the home that has a series of horizontal slats and arranged to permit ventilation but to exclude rain, snow, light, insects, or other living creatures.

Lumens - Unit of measure for total light output. The amount of light falling on a surface of one square foot.