Glossary, 76 terms
Home inspection terms: M
Each definition is the Key Term from the lesson named under it. Where two lessons define a term for different uses, both are here.
- Macerating toilet
- 1. An uncommon toilet that grinds solids into small pieces and ejects them into the drainage system under pressure.
Lesson 35D, Toilets and Bidets - 2. A toilet with a grinding device and a pump that discharges to the gravity drainage pipes.
Lesson 38E, Sewage Ejectors, Backwater Valves and Sump Pumps - Machine bolt
- A bolt secured with a nut and used with a washer at each end to fasten a deck ledger.
Lesson 6B, Deck Materials, Flashing, Ledger Attachment and Deck Stairs - Magnetic-trip circuit breaker
- A breaker that detects a short circuit by the intense magnetic field it generates.
Lesson 24B, Overcurrent Protection, GFCI and AFCI - Main breaker enclosure
- An enclosure holding the panelboard and the service equipment.
Lesson 24A, Service Equipment, Enclosures and Panelboards - Main lug enclosure
- An enclosure whose panelboard is fed by feeder conductors from another panelboard or from the service equipment.
Lesson 24A, Service Equipment, Enclosures and Panelboards - Main lug panelboard
- A panelboard without a main breaker. Its disconnecting means is upstream.
Lesson 24C, Panelboard Defects, Subpanels and Problem Panels - Main vent
- 1. A vent at the far end of a one pipe main or on the dry return, separate from the radiator air vents.
Lesson 33C, Steam Heating Systems and Distribution Piping - 2. The vent through which most of the air in a steam system should be released; at least one per system.
Lesson 33D, Steam Distribution Components, Vents and Traps - Makeup air
- 1. Air that replaces the air an exhaust fan or a clothes dryer removes from the house.
Lesson 16B, Dryer, Kitchen and Bathroom Exhaust - 2. Air that replaces what exhaust appliances remove from a house; not the same as combustion air.
Lesson 30, Heating Fundamentals, Combustion and Capacity - Manifold (plumbing)
- Closely spaced fittings that distribute water or gas to fixtures and appliances.
Lesson 34A, Plumbing Scope and Plumbing Terms - Manifold (vent connector)
- Two or more vent connectors joined before they connect to the vent.
Lesson 30, Heating Fundamentals, Combustion and Capacity - Mansard
- A less common roof style; like the Gambrel, often associated with barns.
Lesson 13A, Roof and Ceiling Framing, Rafters, Ties and Purlins - Mantel
- Decorative facing that frames a firebox opening; it may include a shelf above and vertical trim, called legs, at the sides.
Lesson 39A, Fireplace Types and Terms, Firebox, Hearth and Clearances - Manual J
- 1. The ACCA protocol for calculating the cooling and heating loads of a house.
Lesson 28A, Cooling Systems: Understanding the System - 2. The ACCA protocol for determining heating and air conditioning loads.
Lesson 30, Heating Fundamentals, Combustion and Capacity - Manual S
- 1. The ACCA manual that uses Manual J loads to select equipment capacity.
Lesson 28A, Cooling Systems: Understanding the System - 2. The ACCA protocol that turns Manual J loads into a recommended system capacity.
Lesson 30, Heating Fundamentals, Combustion and Capacity - Manual shutoff valve
- A readily accessible valve in the oil supply piping between the tank and the appliance.
Lesson 38I, Oil Supply, Valves, Filters and Tanks - Manufactured home
- A home often incorrectly called a mobile home; its service equipment is usually on a yard post.
Lesson 24A, Service Equipment, Enclosures and Panelboards - Marketing
- A planned effort to communicate a message to a target market.
Lesson 22, Ethics, Starting a Business and Marketing - Masonry
- In these defect lists, CMU walls and structural brick walls.
Lesson 12E, CMU, Brick, ICF, SIPs and Uncommon Wall Materials - Masonry fireplace
- The traditional fireplace type, nearly always built on site from masonry units such as brick.
Lesson 39A, Fireplace Types and Terms, Firebox, Hearth and Clearances - Masonry headers
- Bricks that bond wythes, with their short side visible on the face at 24 to 34 inch vertical intervals.
Lesson 12E, CMU, Brick, ICF, SIPs and Uncommon Wall Materials - Masonry heater
- A hybrid that is part appliance and part masonry fireplace, storing heat in its masonry mass and giving it off by radiation.
Lesson 39A, Fireplace Types and Terms, Firebox, Hearth and Clearances - Mass wall
- An above-grade wall of masonry, concrete, earth, adobe, structural brick, or solid timber logs.
Lesson 14A, Insulation Scope and Terms, R-Value and How Insulation Works - Mat slab
- A slab-on-grade foundation of one uniform thickness that is essentially a footing; also called a floating slab.
Lesson 11D, Foundation Repairs, Crawl Spaces and Slabs - Mechanical filter
- A filter that removes dirt, sediment, and particulates by passing water through a medium.
Lesson 35F, Water Treatment Devices and Hot Water Circulation - Mechanical stopper
- A bathtub stopper operated from an overflow lever, often found on older bathtubs.
Lesson 35A, Bathtubs - Mechanical ventilation
- In the kitchen and bathroom exhaust rules, any whole-house ventilation method.
Lesson 16B, Dryer, Kitchen and Bathroom Exhaust - Mechanical-powered vent
- A vent used by some Category III and IV water heaters, which are then direct vented or direct exhausted.
Lesson 36B, Electric and Gas Storage Tank Water Heaters - Mechanically attached
- Describes a membrane held to the roof with fasteners.
Lesson 9B, Low Slope Roofing: Modified Bitumen, Foam and EPDM - Media (pads)
- The wet wood fiber or plastic material in an evaporative cooler that air is pulled through.
Lesson 28B, Cooling Systems: Inspecting Equipment and Typical Defects - Mediation
- 1. A process the parties may enter voluntarily, or a court may order before trial.
Lesson 21A, Business Law, Claims and Liability - 2. An ADR process of facilitated negotiation toward a voluntary settlement; it ends if none is reached.
Lesson 21B, Contracts and Insurance - Medium density fiberboard (MDF)
- A composite material used for trim.
Lesson 17A, Interior Walls, Ceilings, Drywall, Plaster and Trim - Meeting rail
- The sash member of a single or double hung window where the two sashes meet.
Lesson 5B, Windows, Window Flashing, Glazing, Window Wells, Escape Openings and Fall Protection - MERV (Minimum Efficiency Reporting Value)
- A filter rating from 1 to 20 for the particle size a filter stops; a larger number stops smaller particles.
Lesson 29, Air Distribution Systems, Ducts, Returns and Filters - Mesh filter
- A disposable fiberglass filter, often white or blue.
Lesson 29, Air Distribution Systems, Ducts, Returns and Filters - Metal pan (cap)
- The metal piece through which a chimney passes at a framed chase.
Lesson 40A, Factory-Built Fireplaces and Chimneys - Metal panel
- A piece of metal roofing of 3 square feet or more.
Lesson 8B, Steep Slope Roofing: Fiber Cement and Metal - Metal plate connected truss
- 1. A truss whose webs are joined to the chords with gusset plates.
Lesson 12B, I-Joists, SCL, Glulam and Floor Trusses - 2. A wood truss whose webs attach to the chords with metal plates.
Lesson 13B, Roof Framing Defects, Trusses and Attic Access - Metal shingle
- A piece of metal roofing smaller than 3 square feet.
Lesson 8B, Steep Slope Roofing: Fiber Cement and Metal - Metal thimble
- A metal fitting that flashes a vent penetration at a roof or a sidewall.
Lesson 32B, Vent Connectors, Category III and IV Vents and Direct Vent Terminations; Lesson 32D, Oil Vent Systems - Metal wall ties
- Ties that bond wythes and may leave no visible evidence of the bond.
Lesson 12E, CMU, Brick, ICF, SIPs and Uncommon Wall Materials - Metal-clad cable (MC)
- A factory-made cable of insulated conductors inside a flexible covering of interlocking aluminum or steel; sometimes called Greenfield.
Lesson 25A, Wiring Methods, Cables and Raceways - Meter base
- The base the electric meter is installed in; its nominal rating usually is not considered in determining service amperage.
Lesson 23B, Grounding, Bonding and the Electrical Service - Meter-main enclosure
- An enclosure with two sections, one for the meter base and one for the panelboard and service equipment.
Lesson 24A, Service Equipment, Enclosures and Panelboards - Metering device
- The device, also labeled an expansion device, that lowers the pressure and temperature of high-pressure liquid refrigerant entering the coil that acts as the evaporator.
Lesson 28A, Cooling Systems: Understanding the System - Meth house
- A house in which methamphetamines or similar drugs may have been made.
Lesson 19C, Deficient Conditions, Service Life and Imminent Threats - Microwave oven (microwave)
- An appliance that cooks by heating food with high frequency electromagnetic radiation.
Lesson 41A, Appliance Scope and Terms, Cooktops, Ranges, Ovens and Dishwashers - Mid-story guide
- A pipe guide that should be installed on CPVC and PEX 2 inches and smaller.
Lesson 34B, Pipe Supports, Copper, CPVC, Galvanized Steel and PEX - Millivolt electric circuit
- The circuit a heated thermocouple completes by bending, which lets the gas valve open.
Lesson 36B, Electric and Gas Storage Tank Water Heaters - Mineral scale
- A deposit left by minerals in the water inside pipes and radiators; it can reduce steam and return water flow.
Lesson 33C, Steam Heating Systems and Distribution Piping - Mineral wool
- Insulation made from natural rock or from slag, a waste product of steel production.
Lesson 14C, Insulation Materials - Mineral-surfaced roll roofing
- A roofing with a base of asphalt-impregnated felt or fiberglass, usually sold in rolls 36 inches wide and about 36 feet long.
Lesson 9A, Low Slope Roofing: Built-Up Membranes and Roll Roofing - Mini-split
- A newer class of room equipment that uses no ducts.
Lesson 28A, Cooling Systems: Understanding the System - Mini-split system
- An air conditioner or heat pump with an outdoor condenser unit and one or more indoor evaporator coil and fan units, serving one or more rooms without ductwork.
Lesson 28B, Cooling Systems: Inspecting Equipment and Typical Defects - Mission tile
- A C shaped tile, also called pan and cover tile.
Lesson 8A, Steep Slope Roofing: Asphalt Shingles and Tile - Mixing valve
- An adjustable valve, also called a tempering valve, that limits the water passing through it to not more than 120 degrees F.
Lesson 36D, Water Heater Installation, Seismic Bracing, Thermal Expansion and Defects - Modular brick
- The most common brick, 7-5/8 by 2-1/4 by 3-5/8 inches.
Lesson 4A, Exterior Scope and Terms, Adhered Masonry Veneer, Metal and Asbestos Cement Siding and Brick Veneer - Modular metal shingle
- A metal shingle stamped to look like another covering, such as slate, wood shakes, or tile.
Lesson 8B, Steep Slope Roofing: Fiber Cement and Metal - Moisture trap
- A space where water vapor condenses, such as between a vapor retarder laid above attic insulation and the attic floor.
Lesson 14B, Vapor Retarders and the House as a System - Molded case circuit breaker
- The modern circuit breaker used in house electrical systems.
Lesson 24B, Overcurrent Protection, GFCI and AFCI - Monitoring
- The action recommendation to watch a system or component in case future action is needed.
Lesson 19B, Deficiency Statements and Recommendations - Monoflow fitting (diverter fitting)
- A directional tee in a one pipe system, with an opening that helps force water up toward the device.
Lesson 33B, Hot Water Heating Systems - Monolithic slab
- A slab-on-grade foundation with footings under interior load-bearing walls and around the perimeter; also called a turned-down edge slab.
Lesson 11D, Foundation Repairs, Crawl Spaces and Slabs - Mortar
- The material binding brick and natural stone veneer units to each other.
Lesson 4A, Exterior Scope and Terms, Adhered Masonry Veneer, Metal and Asbestos Cement Siding and Brick Veneer - Mortar wash
- A sloped mortar covering over racked masonry or a chimney top.
Lesson 39B, Combustion Air, Masonry Chimney Construction, Liners, Flue Area and Defects - Mortise
- A hole chiseled into a framing member to receive a tenon.
Lesson 12E, CMU, Brick, ICF, SIPs and Uncommon Wall Materials - Mortise-and-tenon
- The timber framing joint, secured with a wood peg.
Lesson 12E, CMU, Brick, ICF, SIPs and Uncommon Wall Materials - Motion to dismiss
- A request that the court dismiss the case, filed instead of an answer or within one.
Lesson 21A, Business Law, Claims and Liability - Motor unit
- The opener part that contains the motor and controls.
Lesson 7, Garage Vehicle Doors and Operators - Mound-type system
- A less common septic system that pumps effluent into a raised mound of sand and gravel.
Lesson 38D, Septic Systems - MTBE
- A contaminate usually caused by human activities.
Lesson 35H, Cisterns, Water Quality and Fire Sprinklers - Mud ball
- Mortar that secures the first and last tiles on a hip or ridge.
Lesson 8A, Steep Slope Roofing: Asphalt Shingles and Tile - Mullion
- 1. The vertical member between the panels of a wood door.
Lesson 5A, Exterior Doors and Safety Glazing at Doors - 2. The member that separates joined windows; also the interior trim over that joint.
Lesson 5B, Windows, Window Flashing, Glazing, Window Wells, Escape Openings and Fall Protection - 3. The vertical piece between the panels of a stile and rail door.
Lesson 17B, Interior Doors and Floor Coverings - Multimeter (clamp-on ammeter)
- An electrical meter whose jaws clamp around one energized wire to measure current; its probes measure voltage and resistance.
Lesson 20, Inspection Tools and the Inspection Process - Multiwire branch circuit
- A branch circuit of two hot (ungrounded) wires sharing one neutral (grounded) wire.
Lesson 23B, Grounding, Bonding and the Electrical Service - Muntins
- The vertical bars that hold individual panes in a sash.
Lesson 5B, Windows, Window Flashing, Glazing, Window Wells, Escape Openings and Fall Protection - Mutual assent
- Agreement by both parties to enter a contractual relationship; an older name is a meeting of the minds.
Lesson 21B, Contracts and Insurance
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