O C- On Center- The measurement of spacing for studs, rafters, and joists in a building from the center of one member to the center of the next.

Oakum- Loose hemp or jute fiber that’s impregnated with tar or pitch and used to caulk large seams or for packing plumbing pipe joints

Open hole inspection- When an engineer (or municipal inspector) inspects the open excavation and examines the earth to determine the type of foundation (caisson, footer, wall on ground, etc.) that should be installed in the hole.

Oriented Strand Board or OSB- A manufactured 4′ X 8′ wood panel made out of 1″- 2″ wood chips and glue. Often used as a substitute for plywood.

Outrigger- An extension of a rafter beyond the wall line. Usually a smaller member nailed to a larger rafter to form a cornice or roof overhang.

Outside corner- The point at which two walls form an external angle, one you usually can walk around.

Overhang- Outward projecting eave-soffit area of a roof; the part of the roof that hangs out or over the outside wall. See also Cornice.

Nail inspection- An inspection made by a municipal building inspector after the drywall material is hung with nails and screws (and before taping).

Natural finish- A transparent finish which does not seriously alter the original color or grain of the natural wood. Natural finishes are usually provided by sealers, oils, varnishes, water repellent preservatives, and other similar materials.

NEC (National Electrical Code)- A set of rules governing safe wiring methods. Local codes—which are backed by law—may differ from the NEC in some ways.

Neutral wire- Usually color-coded white, this carries electricity from an outlet back to the service panel. Also see hot wire and ground.

Newel post- The large starting post to which the end of a stair guard railing or balustrade is fastened.

Nonbearing wall- A wall supporting no load other than its own weight.

Nosing- The projecting edge of a molding or drip or the front edge of a stair tread.

Notch- A crosswise groove at the end of a board.

Note- A formal document showing the existence of a debt and stating the terms of repayment.

Nozzle- The part of a heating system that sprays the fuel of fuel-air mixture into the combustion chamber.

Male- Any part, such as a bolt, designed to fit into another (female) part. External threads are male.

Mantel- The shelf above a fireplace opening. Also used in referring to the decorative trim around a fireplace opening.

Manufactured wood- A wood product such as a truss, beam, gluelam, microlam or joist which is manufactured out of smaller wood pieces and glued or mechanically fastened to form a larger piece. Often used to create a stronger member which may use less wood. See also Oriented Strand Board.

Manufacturer’s specifications- The written installation and/or maintenance instructions which are developed by the manufacturer of a product and which may have to be followed in order to maintain the product warrantee.

Masonry- Stone, brick, concrete, hollow-tile, concrete block, or other similar building units or materials. Normally bonded together with mortar to form a wall.

Mastic- A pasty material used as a cement (as for setting tile) or a protective coating (as for thermal insulation or waterproofing)

Mechanics lien- A lien on real property, created by statue in many years, in favor of persons supplying labor or materials for a building or structure, for the value of labor or materials supplied by them. In some jurisdictions, a mechanics lien also exists for the value of professional services. Clear title to the property cannot be obtained until the claim for the labor, materials, or professional services is settled. Timely filing is essential to support the encumbrance, and prescribed filing dates vary by jurisdiction.

Metal lath- Sheets of metal that are slit to form openings within the lath. Used as a plaster base for walls and ceilings and as reinforcing over other forms of plaster base.

Microlam- A manufactured structural wood beam. It is constructed of pressure and adhesive bonded wood strands of wood. They have a higher strength rating than solid sawn lumber. Normally comes in l ½” thickness’ and 9 ½”, 11 ½” and 14″ widths

Milar (mylar)- Plastic, transparent copies of a blueprint.

Millwork- Generally all building materials made of finished wood and manufactured in millwork plants. Includes all doors, window and door frames, blinds, mantels, panelwork, stairway components (ballusters, rail, etc.), moldings, and interior trim. Does not include flooring, ceiling, or siding.

Miter joint- The joint of two pieces at an angle that bisects the joining angle. For example, the miter joint at the side and head casing at a door opening is made at a 45° angle.

Molding- A wood strip having an engraved, decorative surface.

Monopost- Adjustable metal column used to support a beam or bearing point. Normally 11 gauge or Schedule 40 metal, and determined by the structural engineer

Mortar- A mixture of cement (or lime) with sand and water used in masonry work.

Mortgage- Loan secured by land.

Mortgage broker – A broker who represents numerous lenders and helps consumers find affordable mortgages; the broker charges a fee only if the consumer finds a loan.

Mortgage company – A company that borrows money from a bank, lends it to consumers to buy homes, then sells the loans to investors.

Mortgage deed- Legal document establishing a loan on property.

Mortgagee- The lender who makes the mortgage loan.

Mortgage loan- A contract in which the borrower’s property is pledged as collateral. It is repaid in installments. The mortgagor (buyer) promises to repay principal and interest, keep the home insured, pay all taxes and keep the property in good condition.

Mortgage Origination Fee- A charge for work involved in preparing and servicing a mortgage application (usually one percent of the loan amount).

Mortise- A slot cut into a board, plank, or timber, usually edgewise, to receive the tenon (or tongue) of another board, plank, or timber to form a joint.

Mudsill- Bottom horizontal member of an exterior wall frame which rests on top a foundation, sometimes called sill plate. Also sole plate, bottom member of interior wall frame.

Mullion- A vertical divider in the frame between windows, doors, or other openings.

Muntin- A small member which divides the glass or openings of sash or doors.

Muriatic acid- Commonly used as a brick cleaner after masonry work is completed.

Mushroom- The unacceptable occurrence when the top of a caisson concrete pier spreads out and hardens to become wider than the foundation wall thickness.

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.

Lateral (electric, gas, telephone, sewer and water)- The underground trench and related services (i.e., electric, gas, telephone, sewer and water lines) that will be buried within the trench.

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.

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

Ledger (for a Structural Floor)- The wooden perimeter frame lumber member that bolts onto the face of a foundation wall and supports the wood structural floor.

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.

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- An encumbrance that usually makes real or personal property the security for payment of a debt or discharge of an obligation.

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.

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.

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.

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

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.

Keeper- The metal latch plate in a door frame into which a doorknob plunger latches.

Keyless- A plastic or porcelain light fixture that operates by a pull string. Generally found in the basement, crawl space , and attic areas.

Keyway- A slot formed and poured on a footer or in a foundation wall when another wall will be installed at the slot location. This gives additional strength to the joint/meeting point.

Kilowatt (kw)- One thousand watts. A kilowatt hour is the base unit used in measuring electrical consumption. Also see watt.

King stud- The vertical “2 X’s” frame lumber (left and right) of a window or door opening, and runs continuously from the bottom sole plate to the top plate.

Knot- In lumber, the portion of a branch or limb of a tree that appears on the edge or face of the piece.