National Home Inspector Examination® (NHIE) key terms

The weight of people, furniture, snow, and other temporary contents a structure must support. Unlike dead load, it changes over time and is assigned by building code for each room use.

The permanent weight of the structure itself, including framing, roofing, flooring, and fixed finishes. It stays roughly constant for the life of the building and is calculated from material weights.

The continuous route by which forces travel from a roof or floor down through beams, walls, and foundations into the ground. Any break or offset in the path is a structural defect.

The amount a structural member bends or sags under load. Excessive deflection causes cracked finishes, sticking doors, and sloped floors, and it is judged separately from whether the member is strong enough.

The unsupported horizontal distance a floor or ceiling joist covers between bearing points. Span limits come from species, grade, size, and spacing, and exceeding them produces bouncy or sagging floors.

Any location where a framing member rests on and transfers load to another element, such as a beam, wall, or post. Inspectors check for minimum bearing length and direct wood-to-wood contact.

A horizontal beam placed over a door, window, or other opening to carry the loads from above and transfer them to the sides. Undersized or improperly supported headers show as sagging or cracked openings.

The full-height stud nailed directly against a jack stud at the side of an opening. It stiffens the wall and resists lateral movement of the header assembly.

A short stud placed above a header or below a window sill to continue the wall framing and support sheathing and finish. Missing or cut cripple studs weaken the wall above openings.

The horizontal framing member laid on top of the foundation or floor deck to which wall studs are attached. It must be anchored to the foundation and, where required, be pressure-treated or separated from concrete.

A bolt embedded in the foundation that fastens the sill plate to the concrete. Spacing, diameter, and embedment are code-specified, and missing or loose bolts allow the house to shift off its foundation.

A manufactured metal bracket that connects a joist end to a beam or ledger and carries the joist's load. Nails or screws must be the manufacturer-specified type and fully driven, or the hanger fails.

A horizontal member attached to a wall or beam to support the ends of joists, commonly at decks and floor additions. It must be flashed, properly fastened, and never rely on a few undersized fasteners.

Metal or membrane material installed to direct water away from joints and penetrations such as roofs, walls, and decks. Improperly layered or missing flashing is a leading cause of hidden water damage.

A small opening left in a brick, stone, or manufactured-stone wall to let trapped water drain out. Blocked weep holes trap moisture and lead to spalling, efflorescence, and rot of concealed framing.

A white powdery deposit on masonry or concrete left when water carries salts to the surface and evaporates. It signals moisture movement and is often a clue to active leaks or poor drainage.

The breaking away of chips or flakes from concrete or masonry surfaces, usually from freeze-thaw cycles or corroding embedded steel. It reduces section thickness and points to water or reinforcement problems.

The slope of a roof expressed as rise over run, often as a ratio such as 4:12. Pitch determines which roofing materials are allowed and how quickly water drains.

A secondary sheet material laid beneath the finished roof covering or flooring to provide a moisture barrier or a smooth base. Roof underlayment requirements depend on the covering and roof pitch.

Hardware and bracing that keep a house or its components attached and stable during earthquake shaking, such as foundation anchor bolts, hold-downs, and water heater strapping. Requirements vary by region and code edition.

A metal barrier installed over foundation walls and piers to stop subterranean termites from moving from soil into wood framing. It must overlap and be continuous to be effective.

Heating, ventilation, and air conditioning: the systems that control temperature, humidity, and air quality in a house. Inspectors report on the equipment, its energy source, and its distribution and venting.

A heating or cooling system that moves conditioned air through ducts with a blower. Inspectors check the furnace, air handler, duct condition, supply and return registers, and airflow balance.

The metal component in a fuel-fired furnace that separates combustion gases from the air supplied to the house. Cracks or holes allow carbon monoxide into the living space and are a serious safety defect.

Air supplied to a fuel-burning appliance so it burns cleanly and safely. Inadequate combustion air causes incomplete burning, carbon monoxide production, and backdrafting of flue gases.

A condition in which combustion gases spill into the house instead of rising up the flue, often because of depressurization or a blocked chimney. It can be tested with a smoke or flame observation at the draft hood.

A colorless, odorless gas produced by incomplete combustion that is a leading cause of poisoning deaths in homes. Inspectors look for cracked heat exchangers, poor venting, and missing CO alarms near sleeping areas.

The passage inside a chimney or vent that carries combustion gases from an appliance to the outdoors. Flue condition, sizing, and clearance from combustibles all affect safe operation.

A device at the outlet of a naturally drafted appliance that relieves pressure and helps maintain steady draft up the flue. A hood that spills continuously suggests a blocked flue or pressure problem.

The drain pipe that carries water removed from the air by an air conditioner or condensing furnace to a suitable disposal point. Clogged or improperly trapped lines cause water damage and overflow.

A shallow pan placed under an indoor cooling coil or air handler to catch condensate and route it to a drain. A pan without a proper drain or float switch can overflow into ceilings and rooms.

Air drawn back from the conditioned space into the heating or cooling equipment for reconditioning. Undersized or blocked returns cause pressure imbalances, poor performance, and backdrafting risk.

British thermal unit: the amount of heat needed to raise one pound of water by one degree Fahrenheit. It is the common unit for sizing heating and cooling equipment and for comparing appliance output.

Temperature and pressure relief valve: a safety device on a water heater that opens to release excess pressure or temperature. It must be piped to a safe discharge point and never capped or plugged.

A tank that absorbs the volume increase of heated water in a closed system so pressure stays within safe limits. A failed bladder or missing tank can cause relief valve discharge or pipe damage.

An appliance that heats potable water for household use, either in a storage tank or on demand. Inspectors report its energy source, venting, relief valve, and signs of leakage or corrosion.

The document defining what a home inspector must and must not inspect, and the limits of the inspection. It sets minimum scope and is the benchmark for judging whether the inspector performed adequately.

The specific systems, components, and areas an inspection covers, as defined by the standard of practice and the inspection agreement. Work outside that scope is not part of the delivered service.

A system, component, or condition that the standard of practice or the inspection agreement removes from the inspection. Exclusions must be clearly communicated so clients do not assume coverage that was never provided.

A specific issue with a system or component that significantly affects value, usability, or safety, or that poses an unreasonable risk. Inspectors are expected to report these, not to guarantee the absence of all defects.

The practical and contractual constraints on an inspection, such as concealed conditions, inaccessible areas, and the fact that it is a visual, non-invasive, point-in-time review. They are disclosed in the report and agreement.

A written contract signed before the inspection that states scope, fees, limitations, exclusions, and dispute terms. A clear, signed agreement is central to managing client expectations and legal risk.