Home inspection glossary

AFCI: Arc-fault circuit interrupter. A breaker or outlet that shuts off a circuit when it detects dangerous arcing, reducing fire risk. Related guide
Anchor bolts: Bolts that tie the wood sill plate of a house to its concrete foundation, keeping it from sliding in an earthquake. Related guide
As-is sale: A sale in which the seller won't make repairs. In California, sellers must still disclose known material defects.
Backdrafting: Combustion gases from a gas appliance spilling back into the house instead of going up the vent. Related guide
Contingency: A condition in a purchase contract that lets the buyer cancel or renegotiate if it isn't satisfied, such as an inspection or loan contingency. Related guide
Cripple wall: A short wood-framed wall between the foundation and the first floor in raised-foundation homes. Unbraced cripple walls can collapse in earthquakes. Related guide
Double tap: Two conductors connected under a single breaker terminal that is rated for only one. Related guide
Efflorescence: White mineral deposits left on concrete or masonry when water passes through and evaporates. A sign of moisture.
Egress window: A window large enough and low enough for emergency escape from a sleeping room. Related guide
Flashing: Metal or membrane pieces that direct water away from joints, such as where a roof meets a wall or around windows. Related guide
Further evaluation: Report language meaning the inspector saw a sign of a problem and recommends a specialist determine its cause and cost. Related guide
GFCI: Ground-fault circuit interrupter. A device that cuts power when current leaks to ground, protecting against shock in wet areas. Related guide
Grading: The slope of the ground around a house. Proper grading carries water away from the foundation. Related guide
Heat exchanger: The furnace component that transfers heat from combustion to the house air while keeping combustion gases separate. Related guide
Knob-and-tube wiring: Early electrical wiring, generally before the 1940s, using ceramic knobs and tubes. It has no ground conductor. Related guide
Lateral (sewer): The private sewer line running from the house to the public sewer main. Related guide
Ledger board: The board that attaches a deck or balcony to the house. Poor flashing at the ledger is a common cause of rot. Related guide
Natural Hazard Disclosure (NHD): A California disclosure report stating whether a property is in mapped flood, fire, earthquake fault or seismic hazard zones. Related guide
Polybutylene: A gray plastic supply pipe used from roughly 1978 to 1995, known for failures at fittings. Related guide
Post-tension slab: A concrete slab reinforced with steel cables tensioned after the concrete cures. Common in newer Southern California tracts. Related guide
Pressure relief valve (TPR): A safety valve on a water heater that opens if temperature or pressure gets too high. Its discharge pipe must run to a safe location. Related guide
Reserve study: An HOA document estimating the remaining life and replacement cost of shared components, and whether savings are adequate. Related guide
Section 1 and Section 2: Categories in a California termite report: Section 1 is active infestation or damage; Section 2 is conditions likely to lead to it. Related guide
Sediment trap: A short capped pipe at a gas appliance inlet that catches debris before it reaches the controls. Related guide
Standard of practice: A written document defining what an inspector must inspect, what is excluded and how to report. Published by ASHI, InterNACHI, CREIA and others. Related guide
Tempered glass: Safety glass that breaks into small granules. Required near doors, tubs, showers and stairs. Related guide
Transfer Disclosure Statement (TDS): The California form in which sellers disclose the condition of the property and known defects. Related guide
Underlayment: The water-resistant layer beneath roofing material. On tile roofs it is the real waterproofing. Related guide
Weep screed: A metal strip at the base of stucco walls that lets trapped moisture drain out. Related guide
Zinsco: A brand of electrical panel, along with Sylvania-Zinsco, frequently recommended for replacement due to breaker and bus bar problems. Related guide