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Below are terms related to homes and their systems and components. You may encounter these terms in your Home Inspection Report or when communicating with other inspectors or contractors about your home.

D - E

damp-proofing: A process used on concrete, masonry and stone surfaces to repel water in order to prevent the coated surface from absorbing rainwater while still permitting moisture vapor to escape from the structure, as moisture vapor readily penetrates coatings of this type. The term damp-proofing generally applies to surfaces above grade, while the terms waterproofing generally applies to surfaces below grade.

damper: An air valve that regulates the flow of air inside the flue of a furnace or fireplace.

dead load: The static design-weight of a roof and any permanent fixtures attached above or below it.

decay: Disintegration or rot of wood or other substance through the action of mold.

deck: An elevated platform typically located outdoors at a residential structure. The term deck is also commonly used to refer to the above-ground floors in a multi-level parking garage.

deck paint: An enamel paint with a high degree of resistance to mechanical wear designed for use on such surfaces as porch floors.

decorative: Ornamental; not required for the operation of essential systems or components of a home or building.

defensible space: An area around a structure that is cleared of trees, brush, and other potential fuel whose purpose is to slow the rate of an advancing wildfire.

deferred-maintenance items: Deficient items that cannot be remedied with routine maintenance, generally caused by neglect.

deflect: To bend or deform under weight.

deflection: The amount of bending movement of any part of a structural member perpendicular to the axis of the member under an applied load.

density: The mass of substance in a unit volume. When expressed using the metric system, it is numerically equal to the specific gravity of the same substance.

dimensional lumber: Yard lumber from 2 inches up to, but not including, 5 inches thick and 2 or more inches wide, and includes joists, rafters, studs, planks and small timbers.

direct nailing: To nail perpendicular to the main surface or the junction of the pieces joined. Also called face-nailing.

direct-gain system: A passive solar heating system in which sunlight penetrates and directly warms the house's interior.

disconnected: Shut down.

disposer: A device that grinds food sufficiently to enter drains for disposal without clogging them.

distortion: Alteration of viewed images caused by variations in glass flatness or in homogeneous portions within the glass; an inherent characteristic of heat-treated glass.

diverter: A valve that has a single inlet and directs water to one of two outlets. Diverters are used with hand-held showers, shower risers, tub-and-shower combinations, and kitchen faucet sprayers.

diverter valve: A device that changes the direction of water flow from one faucet to another.

door jamb (interior): The surrounding case into and out of which a door closes and opens, consisting of two upright pieces, called side jambs, and a horizontal head jamb.

dormer: A converted attic with windows projecting through a sloping roof.

double coverage: The application of asphalt roofing so that the lapped portion is at least 2 inches wider than the exposed portion, resulting in two layers of roofing material over the roof deck.

double glazing: Two lites of glass in a window that are separated by an air space within an opening to improve insulation against heat transfer and/or sound transmission. In insulated glass units (IGUs), the air between the glass sheets is thoroughly dried and the space is sealed, eliminating the potential for condensation and providing superior insulating properties.

double plate: Two layers of 2x4s that are placed on top of the studs in a wall framing.

double-hung window: A window with sashes that slide vertically and allow opening from the top and bottom.

downspout: The pipe that carries water down from the gutter or scupper. Also called a leader.

drain, waste & vent; drain-waste-ventSee DWV.

dressed-and-matched: Boards or planks machined in such a manner that there is a groove on one edge and a corresponding tongue on the other. Also called tongue-and-groove (T&G).

dressed-size lumber: The dimension of lumber after shrinking from its green dimension and machining it to size or pattern.

drier paint: Oil-soluble soaps of lead manganese or cobalt that, in small proportions, hasten the oxidation and hardening (drying) of the drying oils in paints.

drip: A member of a cornice or other horizontal exterior finish course that has a projection beyond the other parts for the purpose of throwing off water. Also, a groove in the underside of a sill or drip cap to cause water to drop off on the outer edge instead of drawing back and running down the face of a building.

drip cap: A molding placed on the exterior topside of a door or window frame to cause water to drip beyond the outside of the frame.

drip edge: A component designed to prevent water from running back or under an overhang.

drippage: Bitumen material that drips through roof deck joints or over the edge of a roof deck.

drop siding: Siding that is usually 3/4-inch thick and 6 or 8 inches wide with tongue-and-groove or shiplap edges, often used as siding without sheathing in secondary buildings.

dry rot: See fungal wood rot.

dry seal: A weather seal between a window's glass and sash by use of strips or gaskets of neoprene, EPDM, silicone or other flexible material. A dry seal may not be completely watertight.

dry-in: To make a building waterproof.

drywall: A gypsum-board material used for interior walls and ceilings.

drywall hammer: A special hammer with a convex round and checked head used for nailing up gypsum board. Also called an axe and a hatchet.

drywall nail: Nails used for hanging drywall (to be taped and finished later) that have adequate holding power and a head design that does not cut the face paper. They must also be of the proper depth to provide exactly 1 inch of penetration into the framing member. Nails commonly used are chemically-etched and are designed with a cupped head.

duct: A cylindrical or rectangular tube, usually constructed of sheet metal, used as an exhaust/intake channel to distribute warm air from a furnace or cooled air from an air conditioner, or as cold-air returns. The installation is referred to as ductwork.

ductwork: A system of distribution channels used to transmit heated or cooled air from a central HVAC system throughout a home.

dumbwaiter: An elevator with a maximum footage of not more than 9 square feet, not more than 4 inches of headroom, and a maximum capacity of 500 pounds used for carrying materials only.

DuraBoard®, Durock®: A panel made of concrete and fiberglass and used as a ceramic tile backing material on bathtub decks. Also known as WonderBoard®.

dwelling unit: Sometimes used interchangeably with residential unit, a single unit of a multi-unit housing structure (of more than four individual units) that provides complete, independent living facilities, including permanent provisions for living, sleeping, eating, cooking and sanitation.

DWV (drain, waste & vent; drain-waste-vent): The pipes in a plumbing system that remove wastewater.


earthquake strap: A metal strap used to secure gas-fired hot water heaters to the framing or foundation of a house, intended to reduce the chances of having the water heater fall over in an earthquake and cause a gas leak.

eave: The part of a roof that extends beyond the side wall.

eaves flashing: An additional layer of roofing material applied at the eaves to help prevent damage from water backup.

edging strips: Boards nailed along eaves and rakes to provide secure edges for re-roofing with asphalt shingles after cutting back the existing wood shingles.

EER (energy-efficiency ratio): A measure of the instantaneous energy efficiency of cooling equipment. EER is the steady-state rate of heat-energy removal (or cooling capacity) by the equipment in BTU/h divided by the steady-state rate of energy input to the equipment in watts. This ratio is expressed in BTU/h per watt (BTU/h/watt). EER is based on tests performed in accordance with AHRI 210/240 (AHRI 2003).

efflorescence: A white powder that forms on the surface of concrete/masonry walls as a result of water evaporation.

egress: To exit or a means of exiting a building.

EIFS (exterior insulating and finish system): An exterior wall cladding system consisting primarily of polystyrene foamboard with a textured acrylic finish that resembles plaster or stucco.

elbow: An angled fitting that alters the direction of a water line.

electric lateral: The trench or area in a home's yard where the electrical service line from a transformer or pedestal is located, or the work of installing the electrical service to a home.

electric resistance coils: Metal wires that heat up when electrical current passes through them; used in baseboard heaters and electric water heaters.

electrolytic coupling (or dielectric union): A fitting required to join copper to galvanized pipe, which is gasketed to prevent galvanic action, as connecting pipes of different materials may result in electrolysis.

emergency escape and rescue opening: A window allowing for easy escape in an emergency and having minimum dimensions as defined by code and as determined by its location in the home, and required in every bedroom and basement of a home. Also called an emergency egress and rescue opening/window.

emergency shutoff valve: A valve designed to shut off the flow of gases or liquids.

emissivity: The measure of a surface's ability to emit long-wave infrared radiation; important factor in infrared thermography and energy-saving windows.

EMT (electrical metallic tubing): Electrical pipe, also called thin-wall conduit, that may be used for both concealed and exposed areas. It is the most common type of raceway used in single-family and low-rise residential and commercial buildings.

emulsion: In roofing, a coating consisting of asphalt and fillers suspended in water.

energy-efficiency ratioSee EEV.

energy-recovery ventilation (ERV) system: A system that uses air-to-air heat exchangers to recover energy from exhaust air for the purpose of preheating or precooling outdoor air prior to supplying the air to a living space.

escutcheon: A trim piece or decorative flange that fits beneath a faucet handle to conceal the faucet stem and the hole in the fixture or wall.

evidence: Plainly visible and conspicuous material objects or other items presented to the senses that would tend to produce conviction in the mind of an ordinary person as to the existence or non-existence of a fact.

exhaust fan: A fan that extracts air or excess heat from the interior of a home.

expansion coefficient: The amount that a specific material will vary in any one dimension with a change of temperature.

expansion joint: A device used to permit a structure to expand or contract without breakage. In residential construction, a bituminous fiber strip is used to separate blocks, units or slabs of concrete to prevent cracking due to expansion as a result of temperature changes.

expansive soils: Earth that swells and contracts depending on the amount of water present.

exposed: Capable of being inadvertently touched by a person because it is not suitably guarded, isolated or insulated.

exposed aggregate (finish): A method of finishing concrete that washes the cement/sand mixture of the top layer of the aggregate (usually gravel). Often used in driveways, patios and other exterior surfaces.

exposed-nail method: Application of roll roofing by which all nails are driven into the cemented, overlapping course of roofing, leaving the nails exposed to weather.

exposure: The portion of roofing exposed to the elements after installation.

Exposure I-grade plywood: Type of plywood approved for exterior use by the American Plywood Association.

exterior insulating and finish systemSee EIFS.

exterior property: The open space on a property.

eyebrow: A flat concrete projection that protrudes horizontally from a building wall, generally located above a window.

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