Remodeling Glossary

Learn the language of home renovation with our comprehensive glossary of remodeling and construction terms. From A to Z, understand what contractors are talking about.

Updated January 2025
Expert Verified
69+ Terms

A

ABS

Acrylonitrile Butadiene Styrene - A type of plastic pipe commonly used for drain, waste, and vent systems.

Aggregate

Crushed stone, gravel, or other material mixed with cement to make concrete.

Amperage

The strength of an electrical current measured in amperes (amps).

Apron

A piece of trim that covers the rough edge of a window sill or the front of a kitchen sink.

B

Backsplash

A protective wall covering behind a sink, stove, or countertop, typically made of tile, stone, or metal.

Baluster

Vertical supports for a stair railing or deck railing.

Baseboard

Molding that covers the joint between a wall and floor.

Bay Window

A window that projects outward from the main wall of a building.

Beam

A horizontal structural member that supports loads from above.

Bearing Wall

A wall that supports the weight of the structure above it.

BTU

British Thermal Unit - A measure of heat energy used to rate heating and cooling systems.

C

Cantilever

A beam or structure that extends beyond its support, such as a deck overhang.

Casing

Trim molding around doors and windows.

Caulk

A waterproof sealant used to fill gaps and cracks.

Chair Rail

A horizontal molding installed about 3 feet from the floor to protect walls from chair backs.

Circuit Breaker

A safety device that automatically shuts off electrical current when overloaded.

Corbel

A decorative bracket that appears to support a shelf, mantle, or countertop overhang.

Crown Molding

Decorative trim installed where walls meet the ceiling.

D

Drywall

Interior wall covering made of gypsum plaster sandwiched between paper sheets.

Dormer

A window that projects from a sloping roof.

Duct

A tube or conduit that carries air from heating, ventilation, and air conditioning systems.

E

Eaves

The part of a roof that overhangs the exterior wall.

Egress Window

A window large enough to serve as an emergency exit from a basement or bedroom.

Electrical Rough-in

Installation of electrical wiring before walls are closed up.

F

Fascia

A horizontal board that covers the ends of roof rafters.

Flashing

Metal or rubber material used to prevent water leaks at roof joints and penetrations.

Footprint

The outline of a building as seen from above; the area a building occupies.

Frieze

A decorative horizontal band, often found between a wall and ceiling.

G

Gable

The triangular upper part of a wall at the end of a ridged roof.

GFCI

Ground Fault Circuit Interrupter - An electrical safety device that shuts off power when it detects a ground fault.

Grout

A mixture of cement, sand, and water used to fill joints between tiles.

H

Header

A horizontal structural member that spans an opening like a door or window.

HVAC

Heating, Ventilation, and Air Conditioning system.

I

I-beam

A steel beam with an I-shaped cross-section used for structural support.

Insulation

Material used to reduce heat transfer and improve energy efficiency.

J

Jamb

The vertical sides of a door or window opening.

Joist

Horizontal structural members that support floors and ceilings.

K

Knee Wall

A short wall, typically under a sloped ceiling in an attic.

L

Laminate

A synthetic material made of layers, commonly used for countertops and flooring.

Lintel

A horizontal support beam over a door or window opening.

Load-bearing

A structural element that supports weight from above.

M

Millwork

Finished woodwork such as moldings, trim, and built-in cabinets.

Miter Joint

A joint where two pieces meet at an angle, typically 45 degrees.

Mortar

A mixture of cement, sand, and water used to bond bricks or stones.

N

Newel Post

The main post at the start or end of a staircase railing.

O

On Center (O.C.)

The distance from the center of one framing member to the center of the next.

Overhang

The portion of a roof or upper floor that extends beyond the wall below.

P

Penny (d)

A unit of nail measurement; for example, a 16d nail is 3.5 inches long.

Permit

Official approval required before beginning construction work.

Plumb

Perfectly vertical; at a right angle to a level surface.

PVC

Polyvinyl Chloride - A type of plastic pipe used for plumbing and electrical conduit.

Q

Quartz

An engineered stone material made from crushed quartz and resins, used for countertops.

R

Rafter

Sloped structural members that support a roof.

R-Value

A measure of thermal resistance; higher R-values indicate better insulation.

Rough-in

The initial installation of plumbing, electrical, or HVAC systems before walls are finished.

S

Sill Plate

The horizontal wood member that sits on top of a foundation wall.

Soffit

The underside of an architectural element such as eaves, arches, or stairs.

Stud

Vertical framing members in walls, typically spaced 16" or 24" on center.

Subfloor

The structural floor surface beneath finish flooring.

T

Threshold

The bottom part of a doorway; the sill of a door.

Tongue and Groove

A joining method where one board has a projection (tongue) that fits into a groove in another board.

Truss

A prefabricated structural framework, typically triangular, used to support roofs.

U

Underlayment

A layer of material installed under finish flooring to provide a smooth, stable surface.

V

Valley

The internal angle where two roof slopes meet.

Vapor Barrier

A material that prevents moisture from passing through walls and ceilings.

Veneer

A thin layer of material (like brick or stone) applied over another surface.

W

Wainscoting

Decorative paneling that covers the lower portion of interior walls.

Weep Hole

Small openings that allow water to drain from behind retaining walls or masonry.

Z

Zone

A specific area controlled by its own thermostat in an HVAC system.

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