Glossary, 68 terms
Home inspection terms: U and V
Each definition is the Key Term from the lesson named under it. Where two lessons define a term for different uses, both are here.
- U-factor
- A fenestration measure in which a lower number means a higher R-value.
Lesson 15A, Insulation Defects, Water-Resistive Barriers, Radiant Barriers and Fenestration - U-value (factor)
- A measure of how readily a material allows heat transfer; the inverse of R-value.
Lesson 14A, Insulation Scope and Terms, R-Value and How Insulation Works - Ufer ground
- A grounding electrode of concrete-encased #4 rebar or bare #4 AWG copper wire, 20 feet or more in length.
Lesson 23B, Grounding, Bonding and the Electrical Service - Ultraviolet (UV) light
- A disinfection method for water.
Lesson 35F, Water Treatment Devices and Hot Water Circulation - Under mount
- A sink style fastened beneath a hole in the countertop.
Lesson 35C, Sinks - Underground drainage system
- Buried drain pipe used where swales are impractical or where erosion results from natural water flow.
Lesson 2B, Grade, Drainage and Vegetation - Underground feeder (UF)
- A cable similar to NM, designed for wet locations and burial.
Lesson 25A, Wiring Methods, Cables and Raceways - Underlayment
- The layer under a roof covering that provides a water-resistive barrier.
Lesson 8A, Steep Slope Roofing: Asphalt Shingles and Tile - Unfaced batt
- A batt with no vapor retarder.
Lesson 14C, Insulation Materials - Unified Soil Classification System
- The system used to classify soils.
Lesson 11B, Forces and Soils, Footings, Piers and Columns - Uniformly distributed (live load)
- A live load spread evenly over a floor system.
Lesson 12A, Floor Framing, Spans, Bearing, Notching and Boring - Uniformly distributed load
- A load spread evenly over a wall, as distinct from a point load.
Lesson 12C, Wall Systems, Fireblocking and Fire Separation - Unit heater
- A distributed electric heater hung from the ceiling, more common in commercial buildings.
Lesson 33A, Electric Heating Systems - Unsafe
- Describes a condition that meets three criteria together: a serious injury is possible, the risk of it is significant, and it could happen in normal use.
Lesson 19C, Deficient Conditions, Service Life and Imminent Threats - Unseasoned (wet) wood
- Wet firewood, which forms more creosote than dry wood when burned.
Lesson 40B, Draft Problems, Fireplace Inserts, Wood and Pellet Stoves - Unvented appliance
- A gas or oil room heater, fireplace log set, or fireplace with no vent, which expels its combustion gasses into the house.
Lesson 31B, Floor and Wall Furnaces, Room Heaters and Unvented Appliances - Unventilated (closed) crawl space
- A crawl space not vented to the outside.
Lesson 16D, Crawl Space Ventilation and Basement Wall Insulation - UPC symbol
- A mark found somewhere on an AAV and not on a check vent.
Lesson 38C, Vent Systems, Vent Connections and Air Admittance Valves - Urea-formaldehyde foam insulation (UFFI)
- A spray foam used to insulate wall cavities in the 1970s and early 1980s.
Lesson 14C, Insulation Materials - US DOT
- United States Department of Transportation; its rules apply to natural gas piping before the point of delivery.
Lesson 38F, Gas Pipe Materials: Black Steel, Copper and CSST - Valley flashing
- Roof flashing along the line where two roofs of descending slope meet.
Lesson 4C, Exterior Trim, Flashing and Sealants, Eaves and Cornice - Valley jack rafter
- A shortened rafter framed from a valley rafter to the ridge.
Lesson 13A, Roof and Ceiling Framing, Rafters, Ties and Purlins - Valve
- A device that turns a flow of liquid or gas on and off.
Lesson 34A, Plumbing Scope and Plumbing Terms - Valve stem
- The screw that a compression faucet handle turns to raise the seat washer.
Lesson 34D, Faucets, Shower Valves, Hose Bibbs and Aerators - Vapor barrier
- A term, technically questionable, that people often use for vapor retarder; Class I retarders are vapor barriers in effect.
Lesson 14A, Insulation Scope and Terms, R-Value and How Insulation Works - Vapor diffusion
- Water vapor passing through a permeable material from higher to lower vapor pressure.
Lesson 14A, Insulation Scope and Terms, R-Value and How Insulation Works - Vapor diffusion port
- A device that lets water vapor out of a closed attic but blocks air movement in or out.
Lesson 16C, Attic Ventilation and Closed Attics - Vapor drive
- Vapor diffusion increased by heat and vapor pressure.
Lesson 14A, Insulation Scope and Terms, R-Value and How Insulation Works - Vapor impermeable insulation
- Insulation that water vapor does not pass through, such as sheet insulation and closed-cell foam.
Lesson 16D, Crawl Space Ventilation and Basement Wall Insulation - Vapor pressure system
- A steam system operating under 1 psig.
Lesson 33C, Steam Heating Systems and Distribution Piping - Vapor retarder
- 1. A material, classed I, II, or III by perm rating, that slows water vapor flow.
Lesson 14A, Insulation Scope and Terms, R-Value and How Insulation Works - 2. A vapor impermeable material, such as Kraft paper or polyethylene sheeting.
Lesson 14B, Vapor Retarders and the House as a System - 3. The plastic or foil-like outer covering of duct board and flexible duct.
Lesson 29, Air Distribution Systems, Ducts, Returns and Filters - Vaporstat
- A less common device that measures and controls boiler steam pressure.
Lesson 33E, Steam Boiler Components, Solid Fuel and Related Components - Variable expenses
- Costs that rise or fall, at least somewhat, with the number of inspections.
Lesson 22, Ethics, Starting a Business and Marketing - Vaulted ceiling
- 1. A ceiling that slopes up from the top of the full-height walls.
Lesson 11A, Structural Scope and Terms - 2. A ceiling of drywall or another finish material applied to the underside of the rafters.
Lesson 16C, Attic Ventilation and Closed Attics - Vegetation
- All plant materials on a property, such as grass, shrubs, trees, and other ground covers.
Lesson 2B, Grade, Drainage and Vegetation - Veneer
- A decorative surface over a house's exterior walls, usually brick or natural stone.
Lesson 4A, Exterior Scope and Terms, Adhered Masonry Veneer, Metal and Asbestos Cement Siding and Brick Veneer - Vent
- 1. The part of a vent system above the vent connector, usually a chimney or Type B vent and occasionally single-wall pipe.
Lesson 32A, Category I Gas Vent Systems and Vent Defects - 2. The component, often a chimney, through which combustion gasses leave an oil vent system.
Lesson 32D, Oil Vent Systems - Vent (combustion)
- The last vertical component of a vent system.
Lesson 30, Heating Fundamentals, Combustion and Capacity - Vent alarm (vent whistle)
- An alarm at an oil tank vent that helps the delivery person tell when the tank is full.
Lesson 38I, Oil Supply, Valves, Filters and Tanks - Vent cap
- 1. A cap at the top of a vent; single-wall pipe or a Type B vent ending above the roof needs one, or a listed roof assembly.
Lesson 32A, Category I Gas Vent Systems and Vent Defects - 2. The listed cap at the termination of a Type L vent.
Lesson 32D, Oil Vent Systems - Vent connector
- 1. Metal pipe, double-wall or single-wall, carrying combustion products from an appliance into a vent.
Lesson 30, Heating Fundamentals, Combustion and Capacity - 2. The pipe from the appliance to the vent, needed where the appliance is not directly under the vent.
Lesson 32A, Category I Gas Vent Systems and Vent Defects - 3. The pipe running from the appliance to the vent.
Lesson 32D, Oil Vent Systems - Vent connector lateral
- The horizontal part of a vent connector.
Lesson 31B, Floor and Wall Furnaces, Room Heaters and Unvented Appliances - Vent fitting
- A quarter bend made for vent piping, with a very small radius turn.
Lesson 37B, DWV Fittings, Cleanouts and Defects - Vent pipe
- Any pipe that carries air.
Lesson 34A, Plumbing Scope and Plumbing Terms - Vent stack
- 1. A vertical vent running more than one story.
Lesson 34A, Plumbing Scope and Plumbing Terms - 2. A vent pipe serving a few plumbing fixture groups; some houses, older ones especially, may have a larger central one.
Lesson 38B, Plumbing Vents: Purpose, Inspection, Terminals and Size - 3. A vertical vent pipe that individual and branch vents connect to.
Lesson 38C, Vent Systems, Vent Connections and Air Admittance Valves - Vent system
- The passageway for combustion products from the draft hood or flue collar of an appliance to the outdoors.
Lesson 30, Heating Fundamentals, Combustion and Capacity - Vent system height
- The height of the vent and the vent connector together.
Lesson 32A, Category I Gas Vent Systems and Vent Defects - Vent terminal
- The end of a vent pipe where it opens to the outside, above a roof or through a wall.
Lesson 38B, Plumbing Vents: Purpose, Inspection, Terminals and Size - Vent-free heater
- Another name for an unvented appliance.
Lesson 31B, Floor and Wall Furnaces, Room Heaters and Unvented Appliances - Vented gas logs
- A log set installed in a masonry or factory-built wood-burning fireplace, which serves as its combustion chamber and vent.
Lesson 31B, Floor and Wall Furnaces, Room Heaters and Unvented Appliances - Ventilated crawl space
- A crawl space vented to the outside through openings in its walls.
Lesson 16D, Crawl Space Ventilation and Basement Wall Insulation - Ventilated drip edge
- A drip edge that serves as the ventilation cover in open eaves.
Lesson 16C, Attic Ventilation and Closed Attics - Ventilation
- Bringing outside air into a house, or taking inside air out, by natural or mechanical means, either at random through air leaks or by design through heat recovery or energy recovery ventilators or outside air ducts.
Lesson 28A, Cooling Systems: Understanding the System - Ventilation (building)
- Bringing outside air into a house or taking inside air out, by natural or mechanical means.
Lesson 14A, Insulation Scope and Terms, R-Value and How Insulation Works - Vermiculite
- A volcanic rock, made mostly of silicon and oxygen, used as gravel-like insulation.
Lesson 14C, Insulation Materials - Vertical pipe (plumbing)
- A pipe at 45 degrees or more from horizontal.
Lesson 34A, Plumbing Scope and Plumbing Terms - Vertical rise
- The height a vent connector gains before it joins the vent; more rise gives better natural draft.
Lesson 32B, Vent Connectors, Category III and IV Vents and Direct Vent Terminations - Vertical system
- A ground-source loop of tubes drilled into the ground, which needs less land than a horizontal system.
Lesson 28A, Cooling Systems: Understanding the System - Vessel sink
- A sink that sits on top of a cabinet, like an old-style wash basin.
Lesson 35C, Sinks - View port
- The small opening through which an FVIR combustion chamber is seen.
Lesson 36B, Electric and Gas Storage Tank Water Heaters - Vinyl
- A sheet good made from petrochemicals, usually on a fiberglass backing.
Lesson 17B, Interior Doors and Floor Coverings - Vinyl siding (polymer or polymeric siding)
- Siding seen most often as interlocking horizontal strips.
Lesson 4B, Fiber Cement, Hardboard, Insulbrick, Stucco, EIFS, Vinyl, Wood and Wood Structural Panel Siding - Visual observation
- Inspection of the appliance cabinet and of what enters, leaves, and surrounds it, including qualifying access panels.
Lesson 28B, Cooling Systems: Inspecting Equipment and Typical Defects - Vitreous china
- Porcelain, the material of almost all house toilets.
Lesson 35D, Toilets and Bidets - Volatile organic compounds (VOC)
- Pollutants that may be released by furniture, paint, carpet, cabinets, plywood, OSB, and other manufactured products in a house.
Lesson 14A, Insulation Scope and Terms, R-Value and How Insulation Works - Voltage
- The force that moves electricity through conductors, measured in volts and written E.
Lesson 23A, Electrical Terms and Basic Electricity - Voltage sniffer
- An instrument that detects voltage without contact by sensing the magnetic field electricity emits; also called a voltage detector, voltage tester, or tick tracer.
Lesson 20, Inspection Tools and the Inspection Process - Volute
- Handrail formed into a spiral, which may be fitted at the bottom tread for decoration.
Lesson 18A, Stairs, Ramps, Handrails and Guards
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