Resource Center

Bathroom Remodeling Glossary

Plain-language definitions for the materials, fixtures, and terms that come up during a bathroom remodel — no jargon left unexplained.

B

Backer board: A rigid panel — usually cement board or a foam-core waterproofing panel — installed over studs or subfloor as the substrate for tile. It replaces drywall in wet areas because it will not break down when it gets wet.

C

Cement board: A common type of tile backer board made from cement and reinforcing fibers. It is dimensionally stable and water-resistant, but it is not waterproof on its own and still needs a membrane or sealed seams in shower areas.
Curb: The raised threshold at the entry of a traditional shower that keeps water inside the pan. Curbless and zero-entry showers remove this step for a flush, walk-in entry.
Curbless shower: A shower with no raised threshold — the floor slopes gently to the drain so the entry sits flush with the bathroom floor.

D

Demising wall: A wall that separates two functional spaces, such as the wall between a shower and the rest of the bathroom. Relevant when a remodel moves plumbing or reconfigures the room layout.
Ditra: A thin, waffle-patterned uncoupling membrane (made by Schluter) installed under tile over a subfloor. It isolates the tile from minor substrate movement and cracking, and on some assemblies doubles as a vapor management layer.

E

Egress: The path or opening required for someone to exit a room safely — most often discussed in bathroom remodels in relation to window size in a habitable space or door swing clearance.
Escutcheon: The decorative cover plate that conceals the hole or pipe stub-out where a faucet handle, shower valve, or supply line penetrates a wall or fixture, giving a finished look around the opening.

F

Flange: The flat, protruding rim on a fixture — such as a shower pan, tub, or drain — used to anchor it to the surrounding framing or flooring and to create a watertight connection with the waterproofing membrane.
Float (mud float): The process of hand-packing and screeding a mortar bed (traditionally sand and cement, or "mud") to build a sloped shower floor or a flat, level substrate before tile is set.

G

GFCI: Ground-Fault Circuit Interrupter — an outlet or breaker that shuts off power within milliseconds if it detects a current leak, such as from a hair dryer near water. Required by code in bathrooms near sinks and wet areas.
Grab bar blocking: Solid wood or engineered blocking installed inside a wall during rough-in so a grab bar can be anchored into structural framing rather than drywall alone, wherever a bar is planned or may be added later.
Grout: The material that fills the joints between tiles. Sanded grout contains fine sand for added strength in joints wider than about 1/8 inch; unsanded grout is smoother and used for narrow joints and softer tile surfaces that sand could scratch.
Grout (sanded): Grout mixed with fine sand aggregate for strength and shrink resistance in wider tile joints, typically 1/8 inch or larger.
Grout (unsanded): A smoother grout without sand aggregate, used in narrow joints (under about 1/8 inch) and on polished or soft tile surfaces where sand could cause scratching.
Grout haze: The dried, powdery grout residue left on a tile surface after installation, removed during final cleanup with a haze-removal wash and buffing before the tile is considered finished.

H

HydroBan: A liquid-applied waterproofing membrane (made by Laticrete) rolled or brushed directly onto backer board, seams, and corners to create a seamless, flexible waterproof layer under tile.

K

Kerdi: A sheet waterproofing membrane made by Schluter, bonded to backer board with thinset at walls, floors, and corners as part of an engineered shower waterproofing system — a sheet-membrane counterpart to Ditra's uncoupling function underfoot.

L

Linear drain: A long, narrow drain (as opposed to a round center drain) typically set along one edge of a curbless or walk-in shower. It allows the floor to slope in a single direction, which simplifies tile layout in larger showers.

M

Mixing valve: The valve inside a wall that blends hot and cold water to a set temperature before it reaches the shower head or tub spout. Pressure-balancing and thermostatic valves (see Valve) are both types of mixing valves.
Mud pan: A shower floor built from a hand-packed mortar bed sloped toward the drain, as opposed to a prefabricated (prefab) pan. Mud pans allow custom shapes and sizes but take longer to install and cure than a prefab pan.

N

Niche: A recessed shelf built into a shower wall — framed and waterproofed during rough-in, then tiled to match — used to hold shampoo, soap, and other shower items without a separate caddy.

P

PEX: Cross-linked polyethylene tubing used for hot and cold water supply lines. It is flexible, resists freeze-cracking better than rigid copper, and is common in modern bathroom re-piping and remodels.
Pony wall: A short, partial-height wall — often used to separate a toilet area or divide a wet room — that does not run to the ceiling.
Prefab pan: A pre-manufactured shower base (typically acrylic, fiberglass, or composite) installed as a single unit already sloped to its drain, as an alternative to a hand-built mud pan.

R

RedGard: A liquid-applied, roll-on waterproofing and crack-isolation membrane (made by Custom Building Products) used the same way as HydroBan — coated over backer board, seams, and corners before tile to create a seamless waterproof layer.
Rough-in: The phase of a remodel when plumbing, electrical, and framing are installed inside open walls and floors — before drywall, backer board, or finishes go in. Fixture rough-in dimensions (like drain and supply-line placement) must be set before walls are closed.

S

Schluter: A manufacturer of tile-edge trim, waterproofing membranes (including Ditra and Kerdi), and shower pan systems widely specified in tile shower construction. "Schluter system" often refers generally to this style of engineered, membrane-based waterproofing.
Slip resistance (COF): A tile's measured resistance to slipping when wet, expressed as a coefficient of friction (COF). Shower and bathroom floor tile is generally chosen with a higher COF than wall tile for safety underfoot.
Slope (fall): The built-in grade of a shower floor toward the drain — typically about 1/4 inch per foot — that keeps water moving to the drain instead of pooling.
Stub-out: The end of a supply or drain pipe left capped inside a wall or floor during rough-in, ready to be connected to a fixture once finishes are installed.
Subfloor: The structural floor layer (typically plywood or OSB) beneath the finished floor covering. In bathrooms, the subfloor is checked for soundness and moisture damage before new backer board and tile go down.

T

Thinset: A cement-based adhesive mortar, mixed to a thin, paste-like consistency, used to bond tile to backer board, mortar beds, or waterproofing membranes.
Tile-ready: A shower pan or base manufactured with a surface designed to accept tile directly (as opposed to a finished acrylic or fiberglass surface), letting a curbless or custom shower floor be tiled to match the rest of the bathroom.
Trap: The curved section of drain pipe beneath a sink, tub, or shower drain that holds a small amount of water to block sewer gas from entering the room.

V

Valve (pressure-balancing): A shower valve that automatically maintains a steady mix of hot and cold water, adjusting for pressure changes elsewhere in the house (like a toilet flushing) so water temperature does not suddenly spike or drop.
Valve (thermostatic): A shower valve that lets the user set and hold an exact water temperature, and in many installations separates temperature control from flow control (often across two handles) and can supply multiple outlets, like a shower head and a handheld, at once.
Vanity: The cabinet and countertop unit that houses the bathroom sink, along with its plumbing and storage. Vanities range from a single stock cabinet to a custom double-sink piece.
Vapor barrier: A material layer that limits moisture vapor from passing through a wall or floor assembly. In showers, vapor management is typically handled by the waterproofing membrane system rather than a separate polyethylene sheet.

W

Wainscot: A lower wall treatment — tile, beadboard, or paneling — installed to roughly waist or chair-rail height, distinct from a full-height tile wall, often used outside the wet zone of a bathroom.
Wet room: A bathroom where the entire floor is waterproofed and gently sloped to a drain, allowing the shower area to be fully open to the rest of the room with no enclosure, curb, or step.

Z

Zero-entry: A shower or wet room design with no step, lip, or curb at any point of entry, so the floor is level and flush from the bathroom into the shower — commonly specified for aging-in-place and accessible bathroom designs.