main vent: Principal vent to which branch vents may be connected. Also called a main stack.
major defect: A condition of a system or component that renders it non-working, non-performing, non-functioning or unsafe, and requires a professional contractor to further evaluate and repair, correct or replace.
male IPS: Pipe connection whose threads are on the outside of the fitting. See also MIP.
male threads: Standard threads that are on the outside of a pipe or fitting. See also MIP.
mansard roof: A roof that rises by inclined planes from all four sides of a building. The sloping roofs on all four sides have two pitches, with the lower pitch usually very steep and the upper pitch less steep.
mantel: The shelf above a fireplace; also refers to the decorative trim around a fireplace opening.
manual: (1) A manufacturer's book of operating directions. (2) Capable of being operated by hand.
manufactured (mobile) home: A structure, transportable in one or more sections, which, in the traveling mode, is 8 body-feet or more in width or 40 body-feet or more in length, or which, when erected on site, is 320 or more square feet, and which is built on a permanent chassis and designed to be used as a dwelling with or without a permanent foundation when connected to the required utilities, and includes the plumbing, heating, air-conditioning and electrical systems contained in the structure. This term includes all structures that meet the above requirements except the size requirements and with respect to which the manufacturer voluntarily files a certification and complies with the construction and safety standards. The term does not include any self-propelled recreational vehicle. Calculations used to determine the number of square feet in a structure include the total of square feet for each transportable section comprising the completed structure and based on the structure's exterior dimensions measured at the largest horizontal projections when erected on site. These dimensions include all expandable rooms, cabinets, and other projections containing interior space, but do not include bay windows.
manufactured wood: A building component, such as a truss, beam or joist, that is manufactured using small pieces of wood that are glued or mechanically fastened to form a larger piece (such as GLULAM®, which is glued laminated timber). Often used to create a stronger member that may use less wood. See also oriented strand board (OSB).
manufacturer's specifications: The written installation and/or maintenance instructions that are developed by a product's manufacturer which may have to be followed in order to maintain the product's warranty.
mason's hammer: Tool shaped like a chisel that is used to trim brick and stone. Also called a bricklayer's hammer.
masonry: Stone, brick, concrete, hollow-tile, concrete block, gypsum block, and other similar building units and materials, or a combination of the same, bonded together with mortar to form a wall, pier, buttress or similar mass.
masonry primer: An asphalt-based primer used to prepare masonry surfaces for bonding with other asphalt products.
mastic: A heavy-consistency, waterproof compound that is applied to exterior walls and roof surfaces that may remain adhesive and pliable with age.
matched lumber: Lumber that is dressed and shaped in a grooved pattern on one edge and in a tongued pattern on the other.
material: Being both relevant and consequential; crucial.
material defect: A specific issue with a system or component of a property that may have a significant, adverse impact on the value of the property, or that poses an unreasonable risk to people. The fact that a system or component is near, at or beyond the end of its normal useful life is not, in itself, a material defect.
maximum occupancy load: The maximum number of people permitted in a room measured per foot for each width of exit door. The maximum is 50 per foot of exit.
means of egress: A continuous and unobstructed path out of a building to a public way.
mechanic's lien: A lien placed on real property in favor of persons supplying labor and/or materials for a building or structure for the value of their labor and/or materials. In some jurisdictions, a mechanic's lien also exists for the value of professional services. Clear title to the property cannot be obtained until the claim for the labor, materials and/or professional services is settled. Timely filing is essential to support the encumbrance, and prescribed filing dates vary by jurisdiction.
melt point: The temperature at which solid asphalt becomes a liquid.
membrane: A generic term relating to a variety of sheet goods used for certain built-up roofing repairs and applications.
metal edge: Brake metal or a metal extrusion that is secured at the perimeter of a roof to form a weathertight seal.
metal lath: Sheets of metal that are slit and drawn out to form openings and used as a plaster base for walls and ceilings, and as reinforcement over other forms of plaster base.
mezzanine: A semi-permanent, freestanding stair-and-deck system, typically constructed of fiberglass grating, heavy-duty steel and/or aluminum, and installed between two permanent/original floors within an industrial or commercial building in order to provide an open space on and under which can be created informal office areas, storage for inventory, tools and industrial equipment, etc.
MICB (Master Inspector Certification Board): Certifying body that awards the Certified Master Inspector® (CMI) designation.
Microllam?: Brand name for laminated veneer lumber or LVL (and frequently misspelled as Microlam); a manufactured structural wood beam or other engineered wood product that uses multiple layers or strands of thin wood assembled with adhesives and pressure-treated, giving it a higher strength rating than solid-sawn or milled lumber, and making it less likely to twist, warp, bow or shrink because of its composite nature. Normally comes in l-1/2-inch thickness and 9-inch, 11-1/2-inch and 14-inch widths.
migration: Spreading or creeping of a constituent of a compound onto or into adjacent surfaces. See also bleeding.
mil thickness: Measurement used to determine the thickness of a coating; 1 mil = 0.001 or 1/1000-inch.
millwork: Includes building materials made of finished wood and manufactured in millwork plants and planing mills; examples include interior and exterior doors, doorframes, windows, blinds, porchwork, mantels, panelwork, stairways, moldings, and interior trim. It normally does not include flooring, ceilings or siding.
mineral spirits: A byproduct of petroleum, clear in color, and used as a solvent for asphalt coatings.
mineral stabilizers: Finely-ground limestone, slate, traprock and/or other inert material(s) added to asphalt coatings for durability and increased resistance to fire and weathering.
mineral-surfaced roofing: Asphalt shingles and roll roofing that are covered with granules.
minispread: A smaller variation of a widespread faucet with separate spout and handles designed small enough to fit 4-inch center-to-center faucet holes.
minor defect: A condition of a system or component that renders it non-working, non-performing, or non-functioning, and may be repaired, corrected or replaced by a professional contractor or the homeowner.
MIP (male iron pipe): Standard threads that are on the outside of a pipe or fitting.
miter (mitre) 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-degree angle.
mixing valve: A valve that mixes hot and cold water in the valve to obtain a set temperature prior to delivery.
mobile home aluminum roof coating: A durable one-coat application that prolongs the life of mobile home roofs while reflecting the sun's rays and providing a decorative surface; also reduces energy costs.
mock-up testing: Controlled air, water and structural performance testing of existing or new glazing systems.
modified-bitumen roof: A roof covering that is typically composed of a factory-fabricated composite sheet consisting of a copolymer-modified bitumen, often reinforced with polyester and/or fiberglass, and installed in one or more plies. The membrane is commonly surfaced with field-applied coatings, factory-applied granules, or metal foil. The roofing system may incorporate rigid insulation.
modulus: The stress at a given strain; also, tensile strength at a given elongation.
moisture content (of wood): Weight of the water contained in wood, usually expressed as a percentage of the weight of the oven-dried wood.
mold (mould): A form of fungus. Some molds can cause disease in humans.
molding (moulding): A wood strip having a coned or projecting surface used for decorative purposes, such as door and window trim.
monitor: A large structure rising above the surrounding roof planes, designed to give light and/or ventilation to the building's interior.
monopost: An adjustable metal column used to support a beam or bearing point, normally made of 11-gauge or Schedule 40 metal, as determined by the structural engineer.
mopping: In roofing, a layer of hot bitumen that is mopped between plies of roofing felt. Full mopping is the application of bitumen in a manner such that the surface is entirely coated with a reasonably uniform coating. Spot-mopping is the procedure of applying hot bitumen in a random fashion of small daubs, as compared to full mopping. Sprinkle mopping is a special application of installing insulation to the decks by dipping a roof mop into hot bitumen and sprinkling the material onto the deck. Strip-mopping is the application of bitumen in parallel bands.
mortar types: Type M, the strongest type, is suitable for general use and is recommended specifically for masonry below grade and in contact with earth, such as foundations, retaining walls and walks. Type S is suitable for general use and is recommended where high resistance to lateral forces is required. Type N is suitable for general use in exposed masonry above grade and is recommended specifically for exterior walls subject to exposure to the elements. Type O is recommended for load-bearing walls of solid units where the compressive stresses do not exceed 100 pounds per square inch, and the masonry wall will not be subjected to freezing and thawing in the presence of excessive moisture.
mortgage: A loan secured by real property/real estate.
mortgage broker: A person who represents numerous lenders and helps consumers find affordable mortgages; the broker charges a fee only if the consumer qualifies for a suitable 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: A legal document establishing a loan for property.
mortgage origination fee: A charge for work involved in preparing and servicing a mortgage application (usually, 1% of the loan amount).
mortgagee: The lender who makes the mortgage loan.
mortise: An edgewise slot cut into a board, plank or timber to receive the tenon of another board, plank or timber in order to form a joint.
mud cracks: Cracks that develop from the normal shrinkage of an emulsion coating that has been applied too heavily.
mudsill: A wood foundation member, usually a pressure-treated 2x4 or 2x6, bolted to the foundation and on which other framing members can be attached.
mullion: A vertical bar or divider in the frame between windows, doors and other openings that supports and holds items such as panels, glass, sashes, and sections of a curtain wall.
muntins: Horizontal or vertical bars that divide a sash frame into smaller lites of glass. Muntins are smaller in dimensions and weight than mullions.
muriatic acid: Commonly used as a brick cleaner after masonry work is completed.
mushroom: An unacceptable occurrence when the top of a caisson concrete pier spreads out and hardens to become wider than the foundation wall's thickness.
Mylar®: Brand name for a transparent or reflective polyester film or plastic sheeting with a high tensile strength that is used for a variety of products. Field copies of blueprints and plans are frequently manufactured from Mylar.