Bathroom remodeling glossary

Shower construction

Tub-to-shower conversion

Removing an existing bathtub and building a shower in the same floor space. The tub, its surround and the wall material behind it come out, the drain and valve are reworked to suit a shower, and a new pan and wall system go in. It is not the same as a bathtub liner or a surround fitted over the old tub, which leave the original fixture in the wall.

Shower pan

The waterproof floor of a shower, sloped to the drain. It is either a single molded piece set into the room or built on site from mortar and a waterproofing layer. The pan and the wall system meeting it are the two places a shower leaks, which is why they are the two things a leak-free guarantee is written about.

Alcove

A bathing space closed on three sides by walls and open on the fourth. Most American bathrooms put the tub in an alcove, which is why a tub-to-shower conversion so often reuses the same three walls and the same drain. An alcove is the fastest layout to convert because nothing structural has to move.

Curbless shower

A shower whose floor runs continuously into the bathroom floor with nothing to step over, also called a zero-threshold shower. The drain and the slope are built into the floor structure rather than sat on top of it, which makes it straightforward over a basement slab and more involved on a wood-framed upper floor.

Low-threshold shower

A shower with a short curb rather than none, low enough to step over without lifting the knee high. It gives most of the accessibility of a curbless shower without rebuilding the floor structure, which is why it is the common choice on upper floors over wood framing.

Wet room

A bathroom in which the entire room is waterproofed and the shower has no enclosure dividing it from the rest of the floor. The whole floor slopes to a drain. It is the most open and the most accessible arrangement, and the most involved to build, because the waterproofing is no longer confined to one corner.

Recessed niche

A shelf set into the depth of the wall framing to hold bottles, so nothing hangs on the shower head or sits on the floor. It is framed and waterproofed while the wall is open, which is why it has to be decided before the walls close rather than added afterward.

Blocking

Solid lumber fastened between wall studs before the walls are closed, so something can later be anchored where there is no stud. Grab bars, fold-down seats and heavy fittings are all fastened into blocking. It costs almost nothing while the wall is open and means opening the wall again once it is closed.

Curb

The raised lip at the entrance of a traditional shower that keeps water inside. Its height is the single biggest accessibility variable in a shower: a standard curb is a real obstacle to someone using a walker, and lowering or removing it is most of what an accessible conversion is doing.

Linear drain

A long, narrow drain channel rather than a round center drain. Because it collects water along a line instead of a point, the floor can slope in one direction only, which allows large-format tile on a shower floor and makes a curbless entry easier to build.

Shower surround

The wall system enclosing a shower above the pan. It can be tile, or a panel system in acrylic, solid surface or composite stone. The surround is what most people are looking at when they judge a shower, and it is the choice that moves the price the most.

Demolition

Taking out the existing fixtures, wall material and flooring so the new work can start. On a tub-to-shower conversion the demolition is where any hidden condition first becomes visible, which is why a proposal separates the priced work from anything uncovered once the wall is open.

Haul-away

Removing the old tub, wall material and debris from the property and disposing of it. It is worth confirming in writing on any bid, because a bid that quietly excludes it leaves a cast-iron tub in the driveway.

Bathtub liner

A molded acrylic shell, formed to the make and model of an existing tub, fitted over it and sealed at the rim and the drain, often with a wall surround fitted over the existing tile at the same time. The original tub stays in the wall and the step stays where it was. The failure to ask about is water finding its way between the liner and the tub, where it cannot dry out.

Tub refinishing

Spraying a new coating onto the surface of an existing bathtub after it is cleaned, etched and primed, also sold as reglazing or resurfacing. It renews the color and the finish of a sound tub and changes nothing about its shape, its height or what is behind the wall. It is a coating, so it lasts years rather than decades, and abrasive cleaners and suction-cup bath mats are what take it off early.

Corner shelf

A shelf mounted across the corner of a shower on the surface of the walls rather than cut into them. It is how storage is added to a panel or kit shower, whose walls cannot be cut for a niche, and each packaged system comes with its own.

Materials and surfaces

Solid surface

A non-porous sheet material of mineral filler bound in resin, with the color running through the full thickness rather than printed on the face. Because it is solid rather than coated, a scratch can be sanded out. Corian is the best-known brand name for it, and the category is wider than that one name.

Solid composite stone

A panel of natural mineral content bound in resin, with no acrylic or plastic layer, and the pattern running through the material rather than printed on top. It is heavier and more rigid than acrylic, and it sits at the premium end of the panel systems used in a shower.

Acrylic shower system

A shower whose walls and pan are formed from acrylic sheet, usually reinforced from behind. It is the lightest, fastest and least costly of the panel systems, it is warm underfoot, and it is the category most one-day shower advertising is describing.

Cultured marble

A cast material of crushed stone in resin finished with a sprayed gelcoat surface. The pattern lives in that surface layer rather than through the body, so a deep scratch reaches material that does not match. That is what separates it from solid surface.

Gelcoat

A thin pigmented resin layer sprayed onto the face of a molded part to give it its finish. It is what you are touching on a cultured marble or fiberglass fixture. Because it is a surface layer rather than the body of the part, wear goes through it rather than into more of the same material.

Groutless

A wall system whose panels meet in sealed joints instead of the grid of grouted lines tile produces. There is far less line to clean and nothing porous to absorb soap, which is the main practical reason people choose panels over tile. Groutless does not mean sealant-free: the joints are still sealed, and that sealant is still maintenance.

Book-matched

Two panels whose pattern is mirrored along the seam they share, so the veining opens outward from the joint like the two pages of an open book. It is a deliberate effect borrowed from stone slabs, which is why a mirrored seam in the middle of a shower wall reads as intentional rather than as a mismatch.

Glue-up wall kit

A shower surround supplied as a small number of large panels bonded to the wall behind them, rather than assembled from many small pieces. Fewer joints mean fewer places to seal and a faster installation, which is why a panel conversion finishes in days where a tiled one takes longer.

Aluminum composite panel

A rigid sheet built from a core bonded between thin aluminum skins, with the decorative surface printed on the face. It is light, flat and dimensionally stable. The finish is printed rather than solid, so it belongs in a different quality class from solid surface even when it looks similar on the wall.

Porcelain and ceramic tile

Two grades of fired clay tile. Porcelain is fired denser and absorbs less water, which makes it the more durable choice on a floor and in a shower; ceramic is softer and easier to cut. Both are set over a waterproofed substrate, and in a shower what is behind them matters more than which of the two is on the face.

Large-format tile

Tile with any edge longer than about fifteen inches. Large pieces mean fewer grout lines and a calmer wall, but they demand a flatter substrate, because a large rigid piece cannot follow a wall that waves. Flattening the wall first is part of the cost of the look.

Edge profile

A metal or plastic trim piece finishing the exposed edge of tile at a corner or an opening, in place of a bullnose tile. Schluter is the best-known maker. It protects the vulnerable edge and gives a crisp line, and it has to be planned with the tile layout rather than added at the end.

Limescale

The white mineral deposit hard water leaves as it dries: a film on glass, a crust around shower head nozzles and a dull look on walls that are never wiped. It is a cleaning matter rather than damage, removed with a mild acid cleaner the wall maker permits and prevented with a squeegee.

Waterproofing

Waterproofing membrane

The continuous barrier behind a tiled shower that stops water reaching the framing. It is the part of a shower nobody ever sees and the part that decides whether it lasts. Tile and grout are not waterproof on their own; both let water through, and the membrane behind them is what handles it.

Waterproofing assembly

Everything in a shower that together keeps water out of the structure: the pan or base and its bond to the floor, the waterproofing of the walls, whether a membrane behind tile or the sealed panels and seams of a manufactured system, the curb or threshold where there is one, the sealed connection to the drain, and every penetration made through it. It is the thing a leak-free guarantee is written about, as distinct from the tile, glass and trim in front of it.

Sheet and liquid membrane

The two ways a tiled shower is waterproofed. A sheet membrane is bonded over the substrate as a continuous fabric; a liquid membrane is rolled or troweled on in coats and cures into a film. Both work when installed to their maker's specification, and both fail in the same places: corners, seams and penetrations.

Mortar bed

A layer of packed mortar shaped to create slope and support beneath a tiled floor or a fixture. In a shower it establishes the fall to the drain; under a tub it fills the void between the fixture and the subfloor.

Mortar-bedded tub

A bathtub set into a bed of mortar rather than resting on its feet and rim alone. The mortar fills the space under the tub so the base is supported across its whole area, which stops the flex and the creak underfoot that an unbedded tub develops.

Pre-slope

The fall built into the substrate beneath a shower pan's waterproofing, so that any water reaching the membrane runs to the drain rather than standing on it. A pan built without a pre-slope holds water against the membrane indefinitely, and it is one of the most common defects found in a failed shower.

Weep holes

The small openings in the lower body of a traditional shower drain that let water arriving at membrane level escape into the drain. Blocked weep holes trap water under the tile, which is why the setting bed around the drain is kept clear during installation.

Backer board

A cement-based or fiber-reinforced panel used in place of drywall as the substrate for tile in wet areas. It does not soften when it gets wet, which drywall does. It is not itself waterproof, so it is paired with a membrane rather than trusted alone.

Green board

Moisture-resistant drywall, identifiable by its green paper face. It tolerates humidity in a bathroom but it is not a wet-area material and does not belong behind shower tile. Finding it behind a failed shower is a reliable sign of how that shower failed.

Subfloor

The structural sheet material spanning the floor joists, beneath any finished flooring. In a bathroom it is the layer most likely to have taken hidden water damage from an old shower or tub, and it has to be sound before a new pan is set on it.

Joist

One of the horizontal structural members carrying a floor. Joists set the limits of what can move in a bathroom: a drain relocation has to work around them, and cutting or notching one to make room for plumbing is structural work rather than a plumbing detail.

Plumbing and valves

Pressure-balance valve

A shower valve that holds the ratio of hot to cold steady when the pressure on one side changes, so the water does not turn scalding when a toilet is flushed elsewhere in the house. It reacts to pressure rather than to temperature, and it is the type most residential showers use.

Thermostatic valve

A shower valve that holds a set water temperature rather than a set mix, adjusting the blend as the incoming supply changes. It is more precise than a pressure-balance valve and is what allows two outlets to run at once at a controlled temperature.

Anti-scald protection

The requirement that a shower valve limit outlet temperature and hold it steady when supply pressure shifts. It is met by a pressure-balance or a thermostatic valve, and for a new shower valve it is a code requirement rather than an upgrade.

Diverter

The control that sends water to one outlet or another, such as between a fixed shower head and a hand sprayer. It can be built into the valve trim or fitted as a separate control, and it has to be planned with the valve rather than added afterward.

Rough-in valve

The body of a shower valve, set in the wall and connected to the supply pipes before the walls close. It fixes what the finished controls are able to do. The visible handle and plate are a separate part, which is why a finish can be changed later and a function usually cannot.

Valve trim

The visible parts of a shower valve: the handle, the plate behind it and the escutcheon. Trim is chosen for finish and style and is matched to a specific rough-in valve body. That split is why two showers with identical handles can behave differently, and why a trim kit on its own is not a valve.

Hand sprayer

A shower head on a flexible hose that lifts off its holder. It is the most useful accessibility fitting in a shower, because it lets someone seated direct the water rather than move under it, and it makes cleaning the shower itself far easier.

Magnetic dock

A holder that catches a hand sprayer magnetically rather than requiring it to be aimed into a bracket. It matters for anyone with limited hand strength or reach, because returning the sprayer becomes a matter of getting close rather than lining it up.

Slide bar

A vertical rail carrying a hand sprayer holder that moves up and down and locks at a chosen height, so one shower serves people of different heights. It has to be anchored into blocking rather than hung on the wall surface if it is ever to be leaned on.

Flow rate

How much water a shower head delivers, measured in gallons per minute at a stated pressure. Federal rules cap residential shower heads and some states cap them lower. Flow rate is also why a shower running two outlets at once needs its supply and valve sized for the total rather than for one.

P-trap

The curved section of drain pipe below a fixture that holds a plug of water, sealing the room against sewer gas. Every fixture has one. Its position under the floor is part of what makes relocating a drain a structural question rather than a cosmetic one.

Drain relocation

Moving a shower or tub drain to a new position, which means opening the floor and working between or around the joists. It is the most common reason a layout change costs more than it looks like it should, and it is why a conversion that keeps the existing drain is the fastest kind.

Valve cartridge

The replaceable inner part of a shower valve that mixes the hot and cold water and wears with use. When a shower drips or its temperature drifts, the cartridge is usually the part that is changed, from the front through the trim, rather than the valve body in the wall.

Hard water

Water carrying dissolved calcium and magnesium, measured in grains per gallon or milligrams per liter. Central Ohio public systems soften theirs at the plant to a moderately hard level, about seven grains, and the practical effect in a shower is scale on glass and fittings rather than damage.

Water softener

A whole-house appliance that exchanges the calcium and magnesium in hard water for sodium or potassium. It reduces scale and changes how water feels and how much soap it takes, and it is a household decision rather than something a new shower requires.

Water, drains and sewers

Combined sewer

A single pipe that carries both sewage and storm runoff, the way downtown Columbus and the areas around it were first sewered. In dry weather everything reaches the treatment plant; in a heavy rain the pipe can fill and the excess spills to the river through a designed overflow, which is what the city's deep tunnels exist to reduce. By the city's own count, most of its sewer mileage is separate rather than combined.

Sanitary sewer

A pipe that carries only the wastewater from sinks, toilets, tubs and showers to a treatment plant, with rain sent to a separate storm sewer. Nearly all of Columbus and its suburbs are sewered this way, and the rules of each system keep roof water and foundation drainage out of it, because rainwater in a sanitary sewer takes up capacity meant for sewage and is what backs a main up into basements in a storm.

Sewer lateral

The private pipe that carries a house's wastewater from the building to the public sewer main, usually under the yard and out toward the street. Where the owner's responsibility ends and the utility's begins is set by each sewer system and is not the same everywhere in Central Ohio, so it is a question for the utility; a camera run in through the cleanout is how the pipe's condition is read.

Backwater valve

A one-way valve on a building drain that lets wastewater leave and closes if the sewer tries to push back toward the house, so a main surcharged by a storm does not come up through a basement floor drain or a low fixture. Ohio's plumbing code calls for one only where the sewer authority requires it and only for fixtures below the level of the next upstream manhole cover, so whether a basement bathroom gets one is a question for the plan review rather than a default.

Septic system

The private treatment system a house uses where there is no public sewer, called a household sewage treatment system in Ohio's rules: a tank that settles solids, then a soil absorption field or another treatment component. It is sized by the number of bedrooms rather than bathrooms and it is permitted and inspected by the local health district, so a tub-to-shower conversion, which adds no bedroom, does not change the flow the system was sized to.

Water service line

The pipe that brings water from the utility's main in the street into the house, ending at the meter or the main shutoff. Its material decides what the water touches on the way in, its burial depth is set below the local frost line so it does not freeze, and a utility's lead service line inventory is the record of what the public and private halves are made of.

Galvanized steel pipe

Iron or steel water pipe dipped in zinc to slow rust, commonly installed in houses built before 1970 and once used in place of lead for water service lines. A magnet sticks to it, which is how it is told from copper or plastic. The zinc wears through with age, so an old run is where rust and weak flow start, and a valve opened onto galvanized pipe is where a shower conversion usually meets it.

CPVC

Chlorinated polyvinyl chloride, a rigid cream- or tan-colored plastic supply pipe joined with solvent cement, in commercial production since the early 1960s by its maker's own account and still listed in the Ohio Plumbing Code's water pipe tables. It carries hot water and does not corrode. Which material sits behind a given wall follows when the house was plumbed, and the supply pipes page gives the era each source states.

PEX

Cross-linked polyethylene, a flexible plastic supply tubing sold in red, blue and white, joined with crimp, clamp or push fittings and often run from a central manifold to each fixture. It bends around corners without a joint, and a federal housing design guide says it can expand without cracking when the water inside it freezes, where it has room to; by a survey that guide reports, it had reached sixty-three percent of the single-family plumbing market nationally by 2016.

Polybutylene

A gray flexible plastic supply pipe that a federal housing design guide describes as used for supply plumbing from about 1978 to 1995 and no longer approved for it. It appears in neither of the Ohio Plumbing Code's water pipe tables, and it was the subject of a national class-action settlement in 1995. A house from those years may still carry it, and the supply pipes page says what the sources do and do not state about telling the materials apart.

Plumbing vent

The pipe that lets air into the drain system behind flowing water and carries sewer gas out through the roof, so every trap keeps its water seal and no drain gurgles or siphons dry. Every fixture trap needs a vent within a set distance, which is why moving a shower drain more than a short way can mean opening more wall than the shower itself.

Frost line

The depth below the ground surface to which the soil is expected to freeze in winter, which the local building department sets for its own jurisdiction. Footings and water service lines go below it so they neither heave nor freeze, and a supply pipe or a shower valve set into an outside wall above it is the one that freezes in January.

Sump pump

A pump in a pit at the low point of a basement floor that lifts groundwater arriving from the foundation drains and pushes it outdoors or to a storm sewer, keeping it out of the basement and out of the sanitary sewer. In Columbus's Blueprint program a sump pump is installed precisely to take foundation drainage off the sanitary lateral.

Sewage ejector pump

A sealed pump in a basin under a basement floor that lifts wastewater from fixtures sitting below the level of the building's sewer and pushes it up into the drain line. A basement bathroom below the sewer's level needs one; a bathroom on the main floor or upstairs drains by gravity and does not, which is one reason a basement shower is a different job from a hall-bath conversion.

Hot water, fixtures and water quality

First-hour rating

The number of gallons of hot water a storage water heater can deliver in an hour starting from a full tank, which is the figure the federal energy department's sizing method matches to a household's busiest hour rather than the tank's size alone. Two heaters with the same tank can carry different ratings, because the rating also counts how fast the heater recovers while it is being drawn down.

Tankless water heater

A water heater that heats water as it passes through rather than storing it, sized by the flow it can deliver at a given temperature rise. The rise is the difference between the water coming in and the water wanted at the fixture, so the same unit delivers less flow in a Central Ohio winter, when the incoming water is coldest, than in summer.

Heat pump water heater

A storage water heater that moves heat from the surrounding air into the tank instead of making it with a resistance element, using far less electricity for the same hot water. The federal energy department says it needs a certain volume of air around it, cools the room it stands in, and will not work well in a cold space, so where it stands is part of choosing one.

Temperature and pressure relief valve

The safety valve on every storage water heater that opens and discharges water if the tank's temperature or pressure climbs past its setting, with a discharge pipe run to a safe place. The plumbing code requires the valve, sets where its discharge may go, and forbids capping or plugging it; a valve that drips is a symptom to have looked at rather than a nuisance to silence.

Expansion tank

A small pressurized tank on the cold side of a water heater that gives heated, expanding water somewhere to go when a check valve, a backflow preventer or a pressure-reducing valve closes the house off from the main. The plumbing code requires thermal expansion control where such a device is present, and without it the relief valve does the job by dripping.

Hot water recirculation

A loop or a pump that keeps hot water moving between the heater and the far fixtures so the wait at the tap is short, started on demand and shut off automatically, as Ohio's residential energy provisions require, rather than run continuously. The plumbing code limits how far hot water may travel from its source to a fixture, and Ohio's code counts a recirculating loop as a source, which is how a long house meets that limit without moving the heater.

Toilet rough-in

The distance from the finished wall behind a toilet to the center of its drain, measured at the closet flange. Twelve inches is the common dimension and toilets are made in ten- and fourteen-inch versions for houses whose drains were set differently, so a replacement is chosen by measuring the room rather than by preference.

Closet flange

The ring fitting at the top of a toilet's drain, fastened to the floor, that the toilet bolts to and seals against with a wax or waxless ring. The code fastens it to the structure; the makers' instructions put it at the finished floor's level, which is why a floor that is raised or lowered in a remodel usually means resetting the flange, and why the flange is looked at whenever a toilet is off.

WaterSense

The federal Environmental Protection Agency's voluntary label for fixtures that use less water than the federal maximum and pass a performance test, including toilets at 1.28 gallons per flush or less and shower heads at two gallons a minute or less. It is a label on a product rather than a rule about a bathroom, and the federal maximums it improves on are the ones set in 1992.

Consumer confidence report

The annual drinking water quality report every community water system must deliver to its customers under federal rules, listing the source of the water, the contaminants detected, the levels found against the limits, and any violations. Columbus publishes one each year for its three plants, and it is the document a claim about what is in Columbus water should be checked against.

PFAS

Per- and polyfluoroalkyl substances, a large family of manufactured chemicals that persist in the environment and can be found in drinking water sources. The federal Environmental Protection Agency set the first national drinking water limits for several of them in 2024 and proposed changes to that rule in 2026, Ohio EPA sampled the state's community water systems in 2020, and a water system's own results or the state's say what was found at a given plant.

Disinfection byproducts

Compounds such as total trihalomethanes and haloacetic acids that form when chlorine reacts with natural organic matter in the water being treated. They are regulated with their own limits and reported in every water quality report, and a system that treats river water reports them alongside the chlorine that produced them.

Lead-safe renovation

The federal Environmental Protection Agency's rule for renovation, repair and painting work that disturbs painted surfaces in housing built before 1978, which requires a certified firm and a certified renovator, set work practices to contain and clean up dust, and a pamphlet given to the occupants beforehand. It applies to work done for compensation and is separate from lead abatement, which a state license holder performs.

Asbestos-containing material

Building material that contains asbestos fibers, which in a mid-century bathroom can include floor tile and the adhesive under it, pipe insulation, and some plaster, joint compound and ceiling products. The federal Environmental Protection Agency says material in good condition is best left undisturbed, a laboratory analysis of a sample is how it is identified, and Ohio requires abatement to be done by license holders.

Wiring and the floor

GFCI

A ground-fault circuit interrupter, a device in a receptacle, a breaker or a fixture that opens the circuit when it senses current leaking to ground, which is what happens when electricity finds a path through water or a person. The electrical code adopted for Ohio houses requires that protection on bathroom receptacles, and on the wiring of an electric heated floor.

Tub and shower zone

The space the electrical code draws around a bathtub or shower, measured out from the rim or the threshold and up from it, inside which hanging light fixtures, ceiling fans and switches are kept out and any light fixture must be listed for a damp or a wet location. It is the reason the light over a shower is a sealed, listed fixture and the switch is on the wall by the door.

Damp and wet location

Two listings an electrical fixture can carry, defined by the electrical code: a damp location is protected from direct water but subject to moisture, and a wet location is one where water can reach the fixture, as it does inside a shower. A fixture is listed for one or the other by its maker and testing laboratory, and the listing, not the fixture's looks, decides where it may be installed.

Oriented strand board

A structural panel made of wood strands laid in layers and bonded with resin, covered by a voluntary performance standard first approved in 1992 and stamped with a span rating, which is the joist spacing it may bridge as a subfloor. It grew out of the waferboard of the 1960s and, by the accounts of the federal wood laboratory and the housing department, went on to replace plywood in much of American construction; the tile industry's own standards exclude it as a direct base for tile.

Deflection limit

How far a floor may bend under its load, written as a fraction of the span: the Residential Code of Ohio limits a floor to one three-hundred-sixtieth of its span under live load, a figure the federal housing department traces to keeping the plaster ceiling below from cracking. The tile industry's guidance now points at that code figure rather than printing one of its own, and it warns that a stiffer floor is not automatically safe for tile, which is why the floor structure is asked about before tile or stone is chosen.

Movement joint

A soft joint, filled with sealant rather than grout, that the tile industry's guidance places where a tile floor meets a wall, a tub or a change of substrate, and at intervals across a large floor, so the floor can move a little without the tile cracking. The Tile Council says a crack isolation membrane does not remove the need for them and that there must always be soft joints in the tilework, a point it calls a frequent misconception.

Before the bathroom

Privy vault

The lined pit under an outdoor toilet, which held waste until it was emptied by hand. It was the ordinary arrangement in Central Ohio towns before sewers: Columbus counted its vaults in 1890, a state engineer found them within five hundred feet of Westerville's drinking-water wells in 1913, and the state made Worthington ban them within a thousand feet of its new wells as the condition of approving the wells in 1912.

Cistern

An underground tank, usually brick, that collected rainwater from the roof for washing and sometimes drinking, and the reason an old basement may have a bricked-up round chamber in a corner. Columbus's city historian recorded households abandoning their cisterns once the city began delivering softened water in 1908.

Cesspool

A covered pit that received a house's waste water where there was no sewer, letting the liquid soak away into the ground. The Ohio State Board of Health's inspection reports name cesspools and open gullies as where the sewage of some Columbus suburbs went before they built sewers, and its reports are the record of when each town stopped using them.

Sanitary privy

The improved outdoor toilet the United States Public Health Service promoted from the First World War on, with a sealed vault and screened openings so flies could not reach the waste and carry it to food. Federal work-relief crews built 69,796 of them in Ohio on the Federal Works Agency's count through June 1943, which is why a 1930s outhouse in a photograph often looks newer and better built than the house beside it.

Standpipe

A tall vertical tank, open to the water main at the bottom, that stores water and gives a town its water pressure by the height of the column inside it; the water tower is its later form. Fire insurance maps recorded a town's standpipe and its pressure because both decided how far a hose stream would reach, and a Central Ohio town's first standpipe usually dates its first water works.

Census tract

A small, numbered statistical area the Census Bureau uses to publish figures for parts of a city. The Census Bureau's own record puts the first tract data for Columbus at 1930, and its 1950 tract bulletin gives, tract by tract, how many dwelling units had no private bath, no running water, or were dilapidated, which is the nearest thing that exists to a neighborhood count of bathrooms. A tract is drawn for counting, not for a neighborhood's own sense of itself, so a tract figure is printed with its number and its boundaries, never as the name of a neighborhood.

No private bath or dilapidated

A column heading in the 1950 Census of Housing that put two kinds of dwelling unit together in one count: units that had no bathtub or shower for their own exclusive use, and units the enumerator judged dilapidated whatever their plumbing. Because the two are combined, the figure is not a count of missing bathrooms alone, and it is printed on this site with the heading's own words.

Floodwall

A permanent wall, with gates where streets cross it, built to hold a river out of a low-lying district in a flood the levee it replaces could not hold. The Franklinton floodwall on the west side of Columbus was certified complete in 2003 and is designed for the flood with a one-percent chance of occurring in any year; the levee it succeeded was overtopped in March 1913.

The house and its eras

Balloon framing

Balloon framing is an early wood-framing method whose exterior wall studs run in one continuous length from the foundation sill to the roofline, rather than stopping at each floor. Machine-sawn lumber and factory-made nails made this lighter framing practical, and it was largely replaced by platform framing by the start of the Second World War. Opening a wall for a new vent or plumbing chase in a balloon-framed house means opening a stud cavity that runs uninterrupted from the foundation to the roof, not one that stops at the floor above.

Platform framing

Platform framing builds a house one floor at a time: each story is framed and sheathed on its own subfloor, with its own top and bottom plates, rather than running studs past that break as balloon framing does. A federal housing report and a 1955 agricultural handbook both date the switch earlier than usually assumed, calling platform framing the more general method by the start of the Second World War. Opening a wall for a bathroom vent or plumbing run means the stud cavity stops at the floor above, not the roof.

Lath and plaster

Lath and plaster is the wall system that preceded drywall: wood strips, or later metal mesh or a perforated gypsum board called rock lath, nailed across the studs and coated with wet plaster. The National Park Service dates lime plaster into the late nineteenth century, gypsum plaster arriving around 1900, and rock lath used almost exclusively in residential plastering by the late 1930s. Ohio's residential code prints a plaster-thickness table naming these lath types, so a plastered wall is a different system a fixture has to be fastened into, not an obsolete one to remove.

Gypsum board (drywall)

Gypsum board, commonly called drywall, is a panel of compressed gypsum faced with paper, nailed or screwed to studs in place of wet plaster. A federal housing report says plaster remained the dominant wall material until gypsum board took over in the 1960s, and that board runs a half or five-eighths of an inch thick, thinner than the plaster it replaced. Ohio's code also keeps the water-resistant version away from direct water exposure or continuous humidity, so a tub or shower wall calls for a different backer instead.

Brick veneer

Brick veneer is a wythe of brick, nominally three or four inches thick, fastened to a wood-framed wall with corrosion-resistant metal anchors rather than built as a self-supporting masonry wall. The Brick Industry Association's guidance calls for at least a one-inch air space behind the brick, with flashing and weep holes to drain water past it, and notes the design does not rely on the brick's resistance to lateral loads, unlike a solid brick wall. A vent or opening cut through that wall must preserve the air space and flashing, not just the brick.

Mud-set wall tile

Mud-set wall tile is tile set into a thick coat of portland cement plaster, a scratch coat, rather than glued with thin-set to a rigid backer panel. A 1955 federal handbook describes the assembly behind a tub or shower: metal lath over asphalt-saturated felt, then a scratch coat at least five-eighths inch thick, dried before the tile went on. Opening a wall finished this way turns up solid mortar over metal lath rather than the backer board a shower uses today, so patching it removes more of the old wall than expected.

American Foursquare

The American foursquare is a boxy, two-and-one-half-story house form with a raised basement and a one-story porch spanning the front, which the National Park Service says made its appearance in the 1890s and was a fixture of American neighborhoods by the 1930s. Where its bathroom is upstairs, it sits on the same wood floor framing as the bedrooms around it rather than over a basement or a slab, which is the detail that decides how much weight an upstairs tub or a mortar-set tile floor can add before the framing itself becomes the question.

Split-level

A split-level house stacks its rooms in three staggered zones reached by short stairs rather than one full story: a lower level for the garage and family room, a mid-level for the kitchen and living areas, and an upper level for the bedrooms, as the Ohio Modern survey describes the type. The National Park Service counts it, with the ranch, among the dominant suburban forms into the 1960s. Because the bedroom level sits over a living level or a garage rather than a basement, the drain under its bathroom is reached through the ceiling below, which changes how a fixture is moved.

Lustron house

A Lustron house is a prefabricated house built almost entirely of porcelain-enameled steel panels rather than wood framing and drywall. The Lustron Corporation was formed in 1947, and its Columbus plant shipped about 2,680 houses between April 1948 and May 1950, though counts vary between sources. Inside, most wall panels measured two feet by eight feet, except in the kitchen, utility room and bathroom, where panels were two feet square. Opening a bathroom wall in one finds steel panels bolted to a steel frame, not the plaster, drywall or wood stud of any other era.

Built-in tub

A built-in tub is a bathtub enclosed on three sides with a finished apron, rather than standing on legs with open space beneath it. Kohler's own history dates the industry's first one-piece built-in bath with an integral apron to 1911, adopted, Period Homes says, to eliminate the hard-to-clean space under and behind a footed tub. Period Homes calls the five-foot length the common one, and Kohler's 1922 catalog lists four lengths from fifty-four to seventy-two inches, so five feet is the usual size rather than the only one. A bathroom built to that footprint is often too tight for a longer tub.

One-piece tub and shower unit

A one-piece tub and shower unit is a molded fiberglass-reinforced-plastic or acrylic module combining the tub and its shower surround, rather than a tub with separate wall panels around it. Fine Homebuilding traces the shift from carrying a heavy cast iron tub upstairs to a boom in plastics beginning in the 1960s. A 1974 federal patent says a molded one-piece unit must be set in place during construction, while a remodeler's replacement comes in three or four pieces sized to fit through a finished house. Taking one out is therefore a demolition, not a lift.

Primary suite

A primary suite is a bedroom with its own private, attached bathroom, usually along with a walk-in closet, as distinct from a bedroom that shares a hall bathroom with the rest of the house. Because it serves one bedroom rather than the whole household, its bathroom can typically be taken fully out of service for a remodel without leaving anyone else in the house without a working bathroom, which is not true of the single shared bathroom in a house that has only one.

How the pipes reached the street

Storm sewer

A sewer built to carry rain and street runoff only, as distinct from a sanitary sewer carrying household waste. A separate system runs the two in different pipes; a combined system runs both in one. When the Ohio State Board of Health approved storm sewers for the village of Linden Heights in 1909 and 1912, before it had sanitary sewers, each approval was conditioned on an ordinance forbidding anyone to tap them for water closet wastes, sink drainage or household wastes of any kind, which is why an early storm sewer under a street is not evidence that the houses along it had bathrooms.

Relief sewer

A second sewer laid beside or parallel to one that can no longer carry its flow, so that part of the load is taken off the old pipe. The City of Columbus's own survey photographs of 1948 to 1950, held by the Columbus Metropolitan Library, carry contract names for relief sanitary and storm sewers on the South Side, which is one reason the sewer under a street and the house drains that join it can be of different generations.

Force main

A sewer pipe in which sewage is pushed under pressure by a pump, used where gravity cannot carry it to the outfall or the treatment plant. The Ohio State Board of Health's report for 1898 says the two large asylums in the western part of Columbus pumped their sewage through a force main to the Scioto River at Mound Street; a house on a lot below the street sewer uses the same idea on a small scale in a sewage ejector pump.

Night soil

The old term for the contents of a privy vault, so called because it was emptied and carted away by night. The term appears in the villages' own annual returns to the Ohio State Board of Health, which are the record of what a Central Ohio town did with its waste before sewers: Dublin told the Board in 1898 that no arrangements had been made for the removal of garbage or night soil, and in 1899 that night soil was hauled away and in some places on the limestone was carried off through the crevices in the rock.

Public cistern

An underground tank at a street corner, filled by rain or by hauling, that a town kept for fighting fires before it had water mains and hydrants. The Sanborn insurance maps counted them in the title block beside the words they used for the water supply: the February 1885 sheet for Delaware, Ohio, summed up the town's water facilities as indifferent and counted eighteen public cisterns, four years before the water works the same maps later dated to 1889.

Intercepting sewer

A large sewer laid across the mouths of the older sewers that once ran straight to a river, so that their flow is caught and carried to a single outfall or a treatment plant instead. Hooper's 1920 history of Columbus says that when the East Side intercepting sewer was completed in 1892, the dry flow from the main sewers draining the greater part of the city was diverted to a single outfall into the Scioto two and a half miles south of the State House; the same history records that an earlier lateral emptying into Peters Run had created a nuisance in the southern part of the city. An interceptor changes where a city's sewage goes, not what reaches it from a house.

Urban renewal

The federally funded program of the 1950s and 1960s under which cities surveyed blocks as blighted, cleared them and rebuilt them. In Columbus the Goodale project took the neighborhood called Flytown, whose 1950 census tract, number 32, was counted at about 53 percent of dwelling units reporting under the heading No private bath or dilapidated against about 18 percent for the city; the city's own annual report for 1956 described the Goodale program as the clearance of 50 acres of land and the relocation of 753 families.

Mineral spring

A spring whose water carries dissolved minerals, and in the sulfur springs of the nineteenth century the smell of hydrogen sulfide, which writers of the period credited with health. One in Central Ohio is at Delaware, where Ohio Wesleyan University says a hotel called the Mansion House was built in 1833 to accommodate guests to the spring, and where, in the words of the 1880 county history, bathing houses were built close to the water, which invalids patronized. Those bathing houses came decades before the town's water works, which the sources date to 1889.

The ground, the weather and the rules

Karst

Karst is ground shaped by limestone, dolomite or gypsum dissolving underground into sinkholes, caves and drainage through enlarged fractures, as the state geological survey defines it. The survey names the Scioto and Olentangy river gorges, in northern Franklin and southern Delaware counties, as one of Ohio's five most significant karst regions, with sinkhole concentrations reported up to one per acre in parts of Delaware County. It says sudden collapse there can damage or destroy an overlying structure, which is why the survey calls for a site assessment before building on ground in that band.

Radon zone

A radon zone is the federal Environmental Protection Agency's county classification of predicted average indoor radon screening levels: Zone 1 over 4 picocuries per liter, Zone 2 from 2 to 4, Zone 3 under 2. On the agency's Ohio map, Franklin and the counties around it, including Delaware, Licking, Fairfield, Union, Madison and Pickaway, are all Zone 1, the state's highest classification. The map's own instructions say a zone assignment should not decide whether any one home is tested, so a house's own reading comes only from testing that house.

Shrink-swell potential

Shrink-swell potential is the federal soil survey's rating of how much a soil's volume changes as it gains or loses moisture, measured by the change in length of an unconfined clod: low under 3 percent, moderate 3 to 6, high over 6, and very high over 9. The survey says a rating of moderate to very high can damage buildings, roads and other structures. Franklin County's two most extensive soils, Crosby and Kokomo, both rate moderate in the subsoil, not high, so a foundation here is more often working against wetness than against swelling clay.

Drainage class

Drainage class is the Natural Resources Conservation Service's own category for how readily a soil sheds water, from well drained to very poorly drained. Crosby and Bennington, two of Franklin County's most common soils, are rated somewhat poorly drained; Kokomo, the county's single most extensive soil, is rated very poorly drained; Miamian is well drained. The federal soil survey rates Crosby severe for dwellings with basements, citing wetness and low strength, and its stated remedy is grading a building site for surface drainage away from the foundation.

Termite probability

Termite probability is the category the Residential Code of Ohio's design table assigns for the risk of subterranean termite damage, and the entry for the whole state reads moderate to heavy. Because of it, new construction must use one or a combination of six named protections: chemical termiticide treatment, a baiting system, pressure-treated or naturally durable wood, approved physical barriers, or cold-formed steel framing. A rule banning foam plastic below grade applies only where a probability map reads very heavy, which does not include Ohio, so that ban does not reach a Central Ohio foundation.

Ground snow load

Ground snow load is one of the values in the Residential Code of Ohio's design table for climate and geography, used to size a roof structure for the weight of snow it must carry. Unlike the wind speed, weathering and termite entries the state prints for all of Ohio, ground snow load is one of six columns the code leaves blank for the local building department to set for its own jurisdiction. Columbus publishes 20 pounds per square foot; a neighboring jurisdiction may set another figure, so the design depends on where the house sits.

Ice dam

An ice dam is a ridge of ice that forms at a roof's eave when snow above it melts, as the federal Department of Energy's Building America program describes it: the roof deck under the snow warms above freezing, the meltwater runs down the slope, and it refreezes once it reaches the colder deck at the eave. The Residential Code of Ohio's footnote states that every jurisdiction in the state has a history of local damage from ice damming, which is why the code requires ice barrier underlayment on every roof in Ohio.

Egress window

An egress window is the common name for the operable emergency escape and rescue opening the Residential Code of Ohio requires in every sleeping room: a net clear opening of at least 5.7 square feet, a net clear height of at least 24 inches, a net clear width of at least 20 inches, and a sill no higher than 44 inches above the floor. The code exempts a replacement window in an existing opening from the sill and area rules on stated conditions, which is what allows a like-for-like swap in an older bedroom.

Carbon monoxide alarm

A carbon monoxide alarm is the device the Residential Code of Ohio requires in a dwelling with a fuel-fired appliance or an attached garage, placed outside each sleeping area and inside a bedroom whose attached bathroom holds a fuel-burning appliance. The Ohio Board of Building Standards dates the requirement to January 1, 2013, when it entered the code. In an existing house the alarm is triggered whenever an application for approval covers work on a sleeping room, an attached garage, or a fuel-fired appliance, which reaches a remodel touching a water heater or a furnace.

Vitrified clay pipe

Vitrified clay pipe is clay pipe fired hot enough to fuse its surface into a hard, glass-like finish, long used for sewer and drain lines. The U.S. Geological Survey ranked Ohio the country's leading maker of sewer pipe in 1910, with plants in the Hocking and Tuscarawas valleys firing it alongside brick and drain tile, and Logan Clay Products Company, founded on its Hocking County site in 1890 by its own account, says it still makes it. A Tuscarawas County marker names plastic pipe as what displaced the industry, so an old Central Ohio sewer lateral may be this material.

Codes, wiring, water and heat

Model code adoption by reference

Model code adoption by reference is the practice of writing a building code by pointing to a national model code's edition instead of reprinting its text, so the local rule changes when the model or the state does. Ohio's Board of Building Standards adopted the Building Officials and Code Administrators International model as the Ohio Basic Building Codes on September 29, 1978, effective July 1, 1979. Westerville, Worthington, Upper Arlington and Bexley all adopt the Residential Code of Ohio as amended from time to time or in its current edition, so no local ordinance marks the day the code changes.

Certified building department

A certified building department is a county's or a city's own building office, certified by Ohio's Board of Building Standards for specific building types before it may enforce a code on them. The Board's own list shows six of the seven Central Ohio counties holding their own residential certification: Delaware, Franklin, Licking, Madison, Pickaway and Union; Fairfield County's department is certified for commercial construction only, not for houses. Ohio law does not send an uncertified jurisdiction's houses to the state instead: where no certified residential department has jurisdiction, the owner is simply not required to submit plans at all.

Knob-and-tube wiring

Knob-and-tube wiring is two conductors run about an inch off studs and joists on porcelain knobs and through porcelain tubes where they pass through framing, with no grounding conductor and unpolarized outlets. The federal housing department's rehabilitation guide calls it the first widely used electrical system, from the 1890s to 1920; its inspection guide says it is still found in houses built before 1930. The National Electrical Code permits it where it exists and by special permission, but since the 1987 edition bars it from a wall or ceiling cavity filled with insulation that envelops the conductors.

Aluminum branch-circuit wiring

Aluminum branch-circuit wiring is aluminum wire on ordinary 15- and 20-ampere household circuits, which builders turned to in a copper shortage in the mid-1960s and used mainly through the 1960s and early 1970s, by the federal housing department's inspection guide. The Consumer Product Safety Commission says the fire hazard it investigated occurs at connections with aluminum wire, including receptacles, switches, junction boxes and major appliances, and names complete replacement with copper, the COPALUM method and the AlumiConn connector as the only repairs it accepts as permanent. Aluminum branch conductors were run one gauge larger than copper.

Arc-fault circuit interrupter

An arc-fault circuit interrupter is the device the National Electrical Code first required on branch circuits serving dwelling unit bedrooms, starting with its 1999 edition and an enforcement date of January 1, 2002, four years after the first such device reached the market in October 1997. The 2005 edition set January 1, 2008 as the date the industry would change from that first branch-feeder device to the combination type. The 2008 edition then carried the requirement out of the bedroom into family rooms, living rooms, dens, closets, hallways and similar rooms, and the 2014 edition added kitchens and laundry areas.

Service size in amperes

Service size in amperes is the electrical capacity a house's main panel is rated to deliver, and it grew with the appliances. The federal housing department's rehabilitation guide says a house in the early 1900s usually had a 15- or 20-ampere service, and that 40- and 60-ampere services became common as appliances arrived in the 1930s and 1940s. The same guide, written in April 2000, calls 100 amperes the minimum the code requires for new construction; no source read traces that minimum to a code edition.

Flood crest and gage datum

A flood crest is the highest stage a river reaches in a flood, in feet on a gage's own datum, a fixed elevation the gage reads from rather than sea level. The National Weather Service's gage for the Scioto River at Frank Road in Columbus records its highest crest as 27.22 feet on January 22, 1959. The Geological Survey warns that a stage recorded before a channel was straightened or a levee built is not comparable with present gage heights at the same site, so a 1913 stage of 25.9 feet there is not measured against the 1959 record.

Low-head dam

A low-head dam is a low dam that water pours over across its full width rather than storing a reservoir, a type Ohio's dam safety inventory tracks. The inventory lists a Fifth Avenue Low Head Dam and a Rich Street Low Head Dam, owned by the City of Columbus, recorded as abandoned, 8 and 13.5 feet high. The Ohio Environmental Protection Agency reports that a dam on the Olentangy River at Fifth Avenue was removed in a project completed in 2014, and that the river went from failing the modified warmwater habitat criteria to meeting the exceptional warmwater habitat criteria.

House heating fuel

House heating fuel, as the Census Bureau counts it, is the answer to one question: which fuel a household uses most to heat its home, with utility gas defined as gas piped from a central system serving the neighborhood, as distinct from bottled or tank gas. In 1940 the Bureau counted 88.5 percent of Ohio's occupied units reporting a heating fuel as burning coal or coke, and did not tabulate electricity as a heating fuel. In its 2020 through 2024 estimate for Franklin County, 370,219 of 553,099 occupied housing units were heated by utility gas and 169,515 by electricity.

Smoke abatement

Smoke abatement is the regulation of coal smoke from stacks and furnaces, a Columbus city function since March 3, 1913, when the city passed an ordinance to provide for the inspection, regulation and abatement of smoke in the city. A city smoke inspector reported every year under it, and by 1918 the city's own records printed the office as the Division of Smoke Abatement; the federal Bureau of Mines still listed a smoke inspector for Columbus in 1939. As amended in 1916, the ordinance limited dense smoke from a class I stack to six minutes in any one hour.

Offices, windows, coal and the counties

Inspector of buildings

The inspector of buildings was the Columbus office that looked at what was built, and the City of Columbus's own records date it. Its annual report for the year ending March 31, 1892 has the mayor telling council that the Board of Public Works had recently appointed one, and that volume's roster names John T. Harris, with one assistant. Council put the office in an ordinance passed April 10, 1893, and the city's 1896 codification gave it chapter 21, section 182. The 1914 charter made it a Division of Building Regulation inside the Department of Public Safety.

Smoke inspector

The smoke inspector was the Columbus officer who enforced the city's smoke ordinance, and the City of Columbus's annual reports describe the work. His authority was over how a fire was tended: he supervised the ignition, stoking, feeding and attending of steam boiler and other furnace fires. He also issued certificates: no person could use a new or reconstructed plant for producing heat or power until one had been obtained from him. In 1918 the city's Division of Smoke Abatement recorded 732 power and heating plants; the reports for 1947 and 1953 say the division was re-instituted in 1946.

Sanitary inspection

Sanitary inspection is the health department's side of looking at houses, and by the City of Columbus's own records the city's oldest house inspection was the health department's rather than the building department's. In the year ending March 31, 1891 the sanitary police investigated 17,388 nuisances and abated 16,213 of them, and in 1947 the city's division of sanitation recorded 9,773 sanitary inspections of dwellings, 4,128 of tenements and 1,558 of rooming houses. The city describes that side as having charge of nuisance abatement and of the condition of yards, sewer, vaults and water supply.

Double-hung sash

A double-hung window has two sashes that slide past each other in one frame, and the National Park Service says single- and double-hung windows came in at the beginning of the eighteenth century. In its account of a wooden one the lower sash comes out once the interior stop is off, the upper sash is held by a parting bead set into a groove in the center of the stile, and the sash cords run over pulleys to weights in a pocket the agency says is frequently reachable through a door on the frame near the sill.

Hazardous location for glazing

A hazardous location is a place where the Residential Code of Ohio requires safety glazing, and it names seven in Sections 308.4.1 through 308.4.7: in doors; next to doors; in large windows near a walking surface; in guards and railings; at wet surfaces; next to stairs and ramps; and next to the bottom stair landing. The wet-surface rule reaches a bathroom, counting glazing facing a bathtub, shower, spa or sauna whose bottom exposed edge is less than 60 inches above a standing or walking surface. Ohio sends the test to the federal standard, CPSC 16 CFR 1201.

Glass block

Glass block is a hollow glass unit used as a wall or panel, which the Residential Code of Ohio calls glass unit masonry and governs in Section 607: units partially evacuated, with a minimum average glass face thickness of three-sixteenths of an inch, an interior standard-unit panel no larger than 250 square feet, and no reclaimed units. Ohio excepts a panel built to that section from the human impact load test other glazing must pass. The Owens-Illinois Glass Company sold glass block as Insulux, in sales literature the Smithsonian dates from 1937.

Middle Kittanning coal

The Middle Kittanning is the coal seam worked in the Hocking Valley, the field that heated Columbus, and the Ohio Division of Geological Survey says it is known commercially as the No. 6 coal. The survey says the Middle Kittanning of the Hocking Valley area is renowned in Ohio for its thickness of as much as 14 feet, an upper bound for the area rather than a measurement of one mine. Ohio's chief inspector of mines reported Athens, Hocking and Perry Counties together as one Hocking Valley district, in southeastern Ohio and not Central Ohio.

Company town

A company town in the Hocking Valley coal field is a settlement a mining company built to house the workers of its own mine. A National Register nomination says the Hocking Valley Coal Company built the town now known as Eclipse, between 1900 and 1902, to house the workers at its Eclipse Mine No. 4. Ohio History Central says the New Straitsville Mining Company established New Straitsville in 1870 to house its workers. The Ohio Division of Geological Survey says Ohio's Jones Law of 1885 made scrip and overpricing at company stores illegal.

Surface mining

Surface mining takes coal by stripping the ground above it rather than by tunneling, which is why Perry County's production peaks late: the Ohio Division of Geological Survey's county series puts its highest year at 1970, at 3,703,297 short tons, of which 1,146,763 tons came from surface mines. The survey says Ohio's first surface-mine law passed in 1947, and that the General Assembly later passed what it calls the 1972 Ohio Strip Mine Law after the earlier statutes proved weak. It says that law was the model for the federal Surface Mining Control and Reclamation Act of 1977.

Year structure built

Year structure built is the Census Bureau's term for when a building was first constructed, not when it was remodeled, added to or converted, by the Bureau's own subject definitions. It is published in table B25034 and summarized as a median in table B25035, both on a universe of housing units. At the 2020 to 2024 American Community Survey five-year vintage the Bureau puts the median at 2000 in Delaware County, 1984 in Fairfield County and 1980 in Licking County, against 1970 for Ohio. Those are survey estimates carrying a margin of error on every line, not decennial counts.

Complete plumbing facilities

Complete plumbing facilities is a Census Bureau definition that has changed. In the Bureau's 2024 subject definitions it means hot and cold running water and a bathtub or shower, both inside the unit; a flush toilet is not part of it. The 1990 census counted three things, hot and cold piped water, a flush toilet and a bathtub or shower, all inside the unit, so the two are not one series. The Bureau publishes it on two universes: table B25047 for all housing units and table B25048 for occupied housing units only, the gap being vacant units.

Default year built

A default year built is the round year a county auditor's record carries where the office does not know when a house was built. The Delaware, Licking and Fairfield County Auditors' records all do this, so the 1900s row in each is mostly houses of unknown age rather than houses built in that decade; Delaware County's default is 1901 and Fairfield County's is 1900. It is why a decade share read straight off one of those records overstates the 1900s, and why no count of houses built between 1900 and 1909 is taken from them.

Accessibility

Aging in place

Adapting a home so its occupants can keep living in it safely as their mobility changes, rather than moving. In a bathroom it usually means removing the step into the shower, adding secure places to hold and to sit, and bringing the controls and the water within reach of someone seated.

Grab bar

A fixed bar positioned to be gripped while entering, standing in or leaving a shower. Its value is entirely in its anchoring: a bar fastened into blocking or framing will hold a fall and one fastened into drywall with anchors will not. Where the bars go is decided from how the person actually moves, not from a standard drawing.

Fold-down seat

A seat mounted to the shower wall that folds flat when it is not in use, so it takes no floor space and does not collect water. Like a grab bar it is only as good as what it is fastened into, and its height is set for the person who will use it rather than by default.

Roll-in shower

A shower with no threshold at all, entered directly by a wheelchair. It is a curbless shower specified for wheeled access, which adds requirements beyond the missing curb: clear floor space to turn, controls reachable from a seated position, and a drain arrangement that keeps water away from the entry.

Transfer seat

A seat positioned at the shower entry so someone can sit down outside the wet area and then move across into the shower, rather than stepping in while standing. It turns the hardest moment in using a shower from a step into a slide.

Walk-in tub

A deep bathtub with a watertight door in its side and a built-in seat at about chair height. The bather steps over a low sill, sits, closes the door and fills the tub around them, then drains it before the door will open. It keeps a bathtub in the house and removes most of the step; it also means sitting in the tub while it fills and empties, and a wheelchair cannot roll into it.

ADA guidelines

The Americans with Disabilities Act sets accessibility requirements for public accommodations and commercial facilities. It does not govern private homes. Its dimensions are still the best available reference for a residential accessible bathroom, so a home bathroom built to them is following a good standard rather than complying with a law that applies to it.

Glass and doors

Tempered glass

Glass heat-treated so it breaks into small blunt pieces instead of shards. Every piece of glass in a shower enclosure has to be tempered. It cannot be cut or drilled after treatment, which is why shower glass is fabricated to final size rather than trimmed on site.

Frameless glass

A shower enclosure of heavy tempered glass carrying its own weight through hinges and clips, with no metal frame around the panels. It is the clearest and most open look, it is the most costly, and it depends on walls being plumb, because there is no frame to absorb a discrepancy.

Semi-frameless door

An enclosure framed at some edges and unframed at others, most often framed around the perimeter with an unframed door panel. It keeps much of the open look of frameless glass while tolerating ordinary wall conditions, and it sits between framed and frameless on price.

Bypass door

A two-panel sliding door whose panels pass each other on tracks. It needs no swing space, which makes it the usual choice in a small bathroom. The trade-off is that only half the opening is ever clear and the lower track needs cleaning.

Pivot door

A single hinged shower door that swings open. It gives the full opening width and a cleaner look than a slider, and it needs clear floor space outside the shower to swing into, which is the constraint that rules it out in a tight bathroom.

Low-iron glass

Glass made with reduced iron content, so it lacks the green cast ordinary glass shows on its exposed edges and across a large panel. It is a visible upgrade on a large frameless enclosure and largely invisible on a small framed one.

Protective glass coating

A factory-applied treatment that fills the microscopic pores in the glass surface so mineral deposits have less to hold onto and wipe away more easily. It reduces cleaning rather than removing it, and it wears, so it is a maintenance improvement and not a permanent property of the glass.

Made-to-measure glass

Shower glass fabricated to measurements taken from the finished walls rather than ordered to a nominal size. It is why custom glass is measured after the tile or panels are set and arrives after them, and it is one of the few things that most often sets the finish date of a bathroom.

Pricing and project vocabulary

Installed price

A price covering both the product and the labor to fit it, as opposed to a materials-only figure. It is the only kind of number a homeowner can compare directly between bids. A shower advertised at a materials price and one advertised at an installed price are not comparable, and the gap between them is usually most of the cost of the job.

Allowance

A budgeted amount held in an estimate for an item not yet chosen, such as tile or a vanity. It is a placeholder, not a price: the final invoice reflects what is actually selected. An estimate built largely from allowances can be accurate in total and still move considerably once the choices are made.

Planning estimate

A price range produced from stated assumptions, before anyone has seen the room. It is for deciding whether a project is worth pursuing and roughly what to budget. It is not an offer and it binds nobody, which is what separates it from a quote or a proposal.

Line-item proposal

A price broken into named components rather than presented as a single figure. Its value is that it can be checked: a homeowner can see what each part costs, take one out, and see the effect. A single-figure bid can be lower and still be worse, because nothing in it can be examined.

Change order

A written, priced and signed amendment to the agreed scope of work. It is the mechanism that keeps a fixed price fixed. Work added without one is the usual origin of a final bill that does not match the number the homeowner agreed to.

Scope

The specific work a price covers, and by exclusion the work it does not. Most disputes about a remodel are disputes about scope rather than about price, and a written scope is what makes it possible to say whether something is included.

Hidden condition

Something found once demolition opens a wall or floor that could not have been seen when the price was set, such as a damaged joist or non-compliant earlier work. How much of it there is depends on how the work is scoped: a shower whose wall backing and plumbing are all being replaced anyway absorbs most of what turns up behind it, so soft drywall and a spongy patch of floor are ordinary repairs rather than hidden conditions. Handling a real one honestly means pricing it separately and getting approval before continuing, rather than absorbing it silently or adding it to the final bill.

Blue-tape walkthrough

A final inspection in which the homeowner walks the finished room with the contractor and marks anything to be corrected with a piece of tape. The marks become the punch list. It gives the homeowner the first word on what is unfinished rather than the last.

Punch list

The list of small corrections remaining after a project is otherwise complete. A short punch list is normal on any remodel. What matters is whether it is written down, agreed and finished, or left to the homeowner to chase.

Lead time

The wait between ordering an item and receiving it. In a bathroom it is the main reason there is a gap between approving a proposal and the crew arriving: the wall system, pan, valve and door are ordered to the selections made, and the schedule follows the slowest of them.

Stock and special order

Whether an item is held in inventory or made once it is ordered. The difference rarely shows in a catalog and it can add weeks, so it is worth asking which side a chosen color falls on before settling on it rather than after.

Substantial completion

The point at which work is finished enough for the room to be used for its intended purpose, even if minor items remain. It is the milestone final payment is normally tied to, which is why it is worth having defined in writing rather than assumed.

Deposit at signing

The payment made when a contract is signed, which reserves the installation date and places the material orders. Ohio law limits the initial payment a home improvement contractor may collect on larger contracts, so the size of a deposit is partly a legal question rather than purely a commercial one.

Manufacturer warranty

The maker's own promise about a product, on the maker's own terms and process, as distinct from the installer's guarantee on the work of fitting it. A valve, a shower head, a pan or a wall panel each carries one, and they run from a year or two to limited lifetime depending on the product. A written pass-through of those terms is worth asking any installer for, together with a plain statement of which failures are the maker's to answer for and which are the installer's.