make-up air: Air brought into a building from the outdoors through the ventilation system that has not been previously circulated through the system.

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: a shelf or horizontal ornament above a fireplace opening.

manual: capable of being operated by a person.

material: having significant importance, as in “material defect.”  This term is reserved for describing things of significant importance.

material defect: a condition of a commercial property, or any portion of it, that would have a significantly adverse impact on the value of the real property, or that involves unreasonable risk to people on the property. The fact that a structural element, system or sub-system is near, at or beyond the end of the normal useful life of such a structural element, system or sub-system is not, by itself, a material defect.

MCS: Multiple Chemical Sensitivity

means of egress: a continuous and unobstructed path out of a building to a public way.

mechanically attached: A term used to describe a membrane that is attached to the substrate by means of fasteners (nails and plates); also commonly referred to mechanically fastened.

membrane: A slightly flexible covering for a low-slope roof, often acting as the weatherproofing component.

metal edge flashing: Brake metal, sheet metal, or a metal extrusion that is secured at the perimeter of a roof to form a weathertight seal.

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

microbiologicals: Biological Contaminants

modified bitumen (MB): Also referred to as torch-down roofing or rubberized asphalt, composed of polymer-modified bitumen that saturates, impregnates, or fills and coats reinforcement fabric (polyester and/or fiberglass).

mold: a form of fungus. Some molds can cause disease in humans.

mole-rule: A term used to describe ridging that appears as a meandering pattern.

moment connection: A type of joint connection that transfers shear and moment from a beam to a column.

moment (moment of force): A measure that represents the rotational effect about a specific axis caused by a force.

MSDS: Material Safety Data Sheet.

multiple chemical sensitivity: A term used by some people to refer to a condition in which a person is considered to be sensitive to a number of chemicals at very low concentrations. There are a number of views about the existence, potential causes, and possible remedial actions regarding this phenomenon.