Should You Convert Your Tub to a Shower?

Convert the tub if another one exists in the house and the shower is what you use. Keep it if this is your only bathroom, small children live there, or you plan to sell to families. Remodel Now converts tubs to showers across Baltimore County, where the drain, the waterproofing and the floor framing decide how involved the job gets.

Start with how many bathrooms the house has

Before anyone talks tile or glass, answer one question: is there another bathtub in the house?

If the answer is yes, the swap is usually an easy call. The hall bath can become a shower and there is still a tub somewhere for the odd time somebody wants one. If the answer is no, slow down. A house with one bathroom and no tub is harder to sell and harder to live in with a toddler or a dog. That does not mean never. It means deciding it on purpose instead of discovering it later.

The second question is which fixture you actually use. Plenty of people in Woodlawn, Parkville and Towson have a cast iron tub with a curtain and a thirty year old diverter and have not filled that tub since the kids moved out. They step over a fourteen inch wall every morning to shower in a space thirty inches wide at the shoulders. Converting that alcove gives back the width of the tub deck, removes the step, and lets the valve go where you can reach it from outside the spray.

Remodel Now converts tubs to showers in Woodlawn, Towson, Parkville, Owings Mills and the rest of Baltimore County, and handles the same work through the Baltimore-Washington Metro Area. Most of what decides whether the swap goes well happens once the wall is open.

When converting the tub is the right call

Mobility is the most common reason. Stepping over a tub wall with wet feet is the worst movement in a house. A shower with a low curb, a bench, a handheld on a slide bar and real grab bars removes that movement entirely. If somebody has a bad knee, a hip replacement on the calendar, or a plan to stay in the house another twenty years, the conversion is preventive work rather than cosmetic work.

A second case is the primary bath where the tub is dead space. If you have a soaking tub you never fill and a cramped shower you use twice a day, the honest move is to delete the tub and give the floor to the shower. That is the difference between a shower you turn around in and one you back into.

Third is the bath where the tub is the reason the layout does not work. A sixty inch tub eats a whole wall. Replace it with a thirty six by sixty inch shower and you may be able to move the vanity or swing the door the other way. A small bathroom rarely gets bigger, but it can get better organized.

Fourth is the tub that is already failing. Rusted cast iron, a flexing fiberglass unit, a surround caulked over five times that still leaks at the corner. If you are opening the wall anyway, the demolition is not costing you extra. You are only choosing what goes back in. If the tub is sound and you like it, a bathtub replacement is the smaller job and nobody should talk you out of it.

When keeping the tub is the right call

There are three honest reasons to leave the tub alone, and each one deserves a real answer before it gets waved off.

The first is that it is the only bathroom in the house. Converting it means there is nowhere to bathe a small child, nowhere to soak a sprained ankle, and nothing for the next buyer who wants one. If there is a basement or an unfinished space, the better sequence is to add a second bath first and convert the original later.

The second is small children. Washing a two year old in a shower is a bad time for everybody. People do it. Nobody enjoys it.

The third is resale, and it is more specific than most advice admits. Losing one tub in a house with two or three bathrooms is a non-event. Losing the last tub in a three bedroom house marketed to families is a real objection, and you will hear it from an agent. If you are converting with a sale in mind, keep a tub in the house and convert the secondary bath.

  • Convert the tub. What points that way: Another tub exists elsewhere; mobility concerns now or soon; the tub sits unused or is failing; the layout is strangled by a sixty inch fixture.
  • Keep the tub. What points that way: It is the only bathroom; small children at home; last tub in a family house you plan to sell; the tub is sound and you use it.

Drain relocation, the trap arm, and the floor joists

A tub drain sits at one end of the alcove, almost against the wall. A shower drain sits near the middle of the pan, or along one edge with a linear drain. So the drain usually has to move, and moving a drain means opening the floor and getting into the joist bay.

Three code limits drive what is possible. Horizontal drain pipe of two and a half inches or smaller has to fall at least a quarter inch per foot, so it needs vertical room along the whole run. The trap also has to stay close enough to its vent, measured along the pipe from the trap weir to the vent fitting, and for a two inch trap at a quarter inch per foot that limit is eight feet. Finally, the drain and trap get sized from the water you send down them. A shower at 5.7 gallons per minute or less counts as two drainage fixture units and can run a one and a half inch trap. Add a rain head plus body sprays and push past 5.7 gallons per minute and it becomes three fixture units with a two inch trap. People are often surprised that two body sprays change the pipe in the floor.

Then there is the framing, which does not negotiate. In sawn lumber joists a notch cannot exceed one sixth of the joist depth, cannot be longer than one third of the depth, and cannot sit in the middle third of the span. Bored holes cannot exceed one third of the depth and have to stay two inches clear of the top and bottom edges. On engineered I-joists and trusses, cutting and notching are prohibited unless the manufacturer's instructions allow it or an engineer signs off. When a plumber says the drain can only go in one spot, that is usually the joists talking.

If the bath sits over an open basement ceiling, the new trap arm is easy to reach. If it sits over a first floor you just had painted, somebody is opening that ceiling.

Waterproofing the pan and the walls

Everything else in a shower is replaceable. The waterproofing decides whether the ceiling below stays dry for twenty years, and it is invisible once the job is done.

Two approaches are both legitimate. The traditional one is a mortar bed with a sheet liner: a sloped pre-slope bed, a PVC or CPE liner over it clamped to the drain, then a second reinforced mortar bed on top, with weep holes letting water that soaks through the upper bed drain out. The liner has to turn up at least two inches above the finished threshold on every side, cannot be nailed or punctured below one inch above that threshold, and has to be pitched a quarter inch per foot toward the drain. It works when it is built right. It fails when somebody skips the pre-slope, because then water sits in the mortar with nowhere to go.

The other approach is a bonded membrane applied directly over the substrate, either a sheet product or a liquid you roll on. Both have to meet ANSI A118.10, the standard for load bearing bonded waterproof membranes, and both have to go on exactly the way the manufacturer says. Sheet membranes are tougher and bridge small cracks better. Liquid membranes get into tight corners more easily. Neither forgives a thin spot at a corner or a missed seam at the curb.

Either way the liner gets flood tested: plug the drain, fill the pan to at least two inches measured at the threshold, hold it fifteen minutes, look for leakage. Ask whether your installer flood tests. If the question surprises them, that tells you something.

The walls matter too. Waterproof wall material has to run at least six feet above the floor and at least seventy inches above the shower drain, and the walls have to form a watertight joint with each other and with the shower floor. Tile and grout are not waterproofing. They are the wear surface over it, which is why the tile decision and the membrane decision are separate conversations.

Curb, curbless, and what a zero threshold does to the subfloor

Curbless looks simple in photos. It is the most structural decision in the project.

A standard curb is a built up dam at the entry, usually a couple of courses of blocking or a preformed curb, waterproofed over the top and down both faces. It keeps water in, leaves the framing untouched, and is why a tub to shower swap can often stay inside the existing alcove without touching the floor structure.

Curbless means the finished shower floor has to sit low enough that water runs to the drain instead of out across the bathroom. In practice that means dropping the pan area two to four inches below the surrounding floor: removing subfloor and either sistering lower members alongside the existing joists, framing a new recess between them, or building the rest of the bathroom floor up to meet the shower. Over sawn joists with depth to spare, sistering down is workable. Over engineered I-joists you are not notching anything, so the realistic options are a framed recess or raising the room.

A linear drain helps. Sloping the pan one direction toward a slot needs less total drop than sloping four planes to a center point, and it lets you run large format tile without cutting it into pinwheels. It also matters that the code's flood test assumes a threshold, so with no curb a temporary dam gets built just to run the test.

  • Standard curb. What it takes: Easiest to waterproof, no floor framing work, keeps water in reliably; you still step over something.
  • Low curb or ramped entry. What it takes: Most of the accessibility benefit for modest floor work.
  • Curbless. What it takes: Best for mobility and the cleanest look; needs a dropped subfloor, framing work, a linear drain, and exact slope at the open edge.

Whichever entry you pick, the compartment has to hold at least 900 square inches with no dimension under thirty inches, measured at the top of the threshold and carried up seventy inches above the drain, with an entry opening at least twenty two inches clear. Thirty by thirty is the code floor. Thirty six by thirty six is where a shower starts to feel like one.

Glass versus a curtain

A curtain is cheap, replaceable, and lets the whole bathroom get humid. Glass contains the spray, shows every water spot, and has to be measured against walls that are actually plumb.

If you go with glass, two things matter. One is safety glazing. Glass in a shower enclosure where the bottom exposed edge sits less than sixty inches above any standing or walking surface counts as a hazardous location, which means tempered or otherwise approved safety glazing carrying a permanent manufacturer's designation you can still see after installation. Any legitimate shower door meets this. It is also why a salvaged window pane does not belong in a shower wall.

The other is the wall. Frameless panels are cut to the opening and have almost no adjustment. In a house from the fifties with plaster over lath and a stud wall that leans half an inch over seven feet, a frameless panel will either show a wedge of daylight at the top or need a scribed filler strip. The fix happens during framing: plumb and fur the walls before the backer board goes on. Nobody can fix it afterward. If you want frameless glass, say so before the walls close up.

In a hall bath that gets hard use, a semi-frameless door with a header and a bottom sweep is often the smarter call than a heavy frameless slab.

Blocking for grab bars, and framing the niche

The cheapest accessibility work in a bathroom is blocking you install while the wall is open and may never use.

Industry planning guidance is to reinforce tub and shower walls during construction so a grab bar can later be mounted and support a static load of 250 pounds, with bars set 33 to 36 inches above the floor, 1.25 to 2 inches in diameter, held an inch and a half off the wall. Those numbers come from the accessible standards, which a single family house is not legally required to meet. Ask for blocking to them anyway, because the alternative is opening tile later to find a stud.

Practical version: flat 2x8 or 2x10 blocking let into the studs on the back and control walls, continuous from about 30 to 40 inches, plus a vertical block near the entry. Ask for a photograph of it before the backer board goes on. Five years from now that photo is what lets somebody place a bar without guessing.

The niche is the other thing decided before drywall. A recessed niche goes between studs, so it lands where the studs are, not where the drawing says. Keep it off the wet wall so you are not framing around supply lines and the shower valve. Keep it out of an exterior wall if you can, because a niche in a 2x4 exterior wall with no continuous insulation leaves a cold spot that fogs and drips in February. Slope the shelf slightly toward the shower, waterproof it with the same membrane that covers the walls, and treat the shelf to wall joint as a corner that will move.

One more thing worth settling before the wall closes. A shower puts far more moisture into the room than a tub with a curtain did, and ventilation is its own scope of work rather than part of the tile and plumbing package, so ask early who is carrying it and get the answer in writing.

Permits and licensing: who pulls what, county by county

Permits in Maryland are a county matter, and the answer genuinely changes across a county line.

In Baltimore County, the Department of Permits, Approvals and Inspections states plainly that an alteration permit is required for commercial bathrooms but not for residential bathrooms, while plumbing and electrical permits are always required. The plumbing side is stricter than people expect: a permit is required for all plumbing and gasfitting work, and only a Baltimore County licensed plumbing or gasfitting contractor can apply for it. Not a Maryland plumber generally. A county licensed one. The county building code runs on the 2021 International Residential Code family, and the plumbing and gasfitting code adopts the 2021 International Plumbing Code with county amendments. Those amendments add that work concealed before inspection has to be made accessible again until the inspections are complete, and that a reinspection fee can be charged when the inspector arrives and the work is not ready.

Inside Baltimore City, permits go through the Department of Housing and Community Development instead, with its own e-permits system and plumbing licensing. A Woodlawn or Catonsville address is Baltimore County, not the City.

In Montgomery County, the Department of Permitting Services issues the interior alteration permit, but its own homeowner permit guide lists plumbing with the instruction to contact WSSC. That surprises people. In both Montgomery and Prince George's, WSSC Water licenses the plumbers and issues the plumbing permits, and most plumbing work has to be performed by a WSSC licensed plumber or gasfitter. Prince George's building permits come from the Department of Permitting, Inspections and Enforcement, Howard County from Inspections, Licenses and Permits, and Anne Arundel County from Inspections and Permits, where a plumbing permit is required for adding or relocating fixtures and piping, including piping roughed in for future use. A conversion in Rockville follows a different paper trail than the identical job in Owings Mills.

Licensing is statewide. Only contractors licensed by the Maryland Home Improvement Commission may contract with a homeowner for home improvement work. The license number belongs on the contract with the company name, address and phone number, and anyone can look it up in the Commission's public license search. Maryland also requires a notice giving the Commission's phone number and website and explaining that it administers a Guaranty Fund that may compensate homeowners for certain actual losses. A contract without a license number on it is not suffering a clerical oversight.

A 1950s Woodlawn bath versus a 2005 one

The age of the house decides which surprises show up.

In a house from the forties, fifties or early sixties, which describes a lot of the housing stock in Woodlawn, Catonsville and Parkville, expect some mix of the following. Plaster over wood or gypsum lath, which comes off in sheets and takes the key with it. A cast iron tub set in mortar, often too big to carry out of a narrow hall intact, so it gets broken up in place. Galvanized steel supply spliced to copper somewhere in the past, which is where corrosion concentrates. A cast iron drain with a caulked lead joint at the closet bend. A tub that was never properly vented, discovered the moment the floor comes up. A diagonal one by board subfloor too uneven to tile over without plywood or a self leveling pour. Old floor tile and black mastic that may contain asbestos and gets tested rather than guessed at. And almost certainly paint old enough that the federal lead rule applies, because paid work disturbing paint in housing built before 1978 has to be done by an EPA Lead-Safe certified firm using a certified renovator and contained work practices.

In a house from the late nineties or 2000s the bones are better and the problems are different. Drain, vent and supply are PVC and copper or PEX, correctly sized and already vented. The alcove is a true sixty inches, so a standard base drops in. But the tub is a one piece fiberglass or acrylic unit set before the drywall went on, which means it does not come out through the door and gets cut into pieces. The floor is OSB, which needs an uncoupling membrane under tile rather than thinset straight onto the panel. And the joists are very often engineered I-joists, which is the biggest reason a curbless shower in a 2005 colonial is a longer conversation than the same request in a 1955 Cape Cod framed with 2x8s.

Neither era is harder across the board. The old house hides more. The new house constrains more.

Questions worth asking before you sign anything

A conversion is a small job with a lot of buried decisions, so the questions that matter are not about tile.

Ask who is pulling the plumbing permit and under whose license, and in Baltimore County whether that plumber holds a county license. Ask what waterproofing system goes in, whether it meets ANSI A118.10 if it is a bonded membrane, and whether there is a pre-slope under the liner if it is a mortar system. Ask whether the pan gets flood tested before tile and whether you can watch. Ask where the existing vent is and whether the new trap arm stays inside the allowed distance from it, because that answer decides where your drain can go. Ask whether the joists are sawn lumber or engineered, since that decides whether curbless is even on the table. Ask for blocking behind the walls for future grab bars, and for a photo of it. Ask who is carrying ventilation, since it sits outside the tile and plumbing scope. Ask what happens, in writing, if the wall opens and there is rot in the sill or a leak that has been running into the joist bay.

Then ask what pushes the number up or down. On a conversion the honest answers are whether the drain moves and how far, whether the vent gets reworked, whether the floor structure gets touched for a curbless pan, whether the house is old enough to need lead safe practices and asbestos testing, how much galvanized pipe gets replaced while the wall is open, tile size and layout, how much glass and whether it is frameless, and whether this is the only bathroom in the house.

Most of those answers come from somebody standing in the room with the alcove in front of them. Remodel Now has been in business in Baltimore County since 2001 and handles tub to shower conversions along with the rest of its bath conversions. Questions can go to (301) 798-4696 or the contact page. If the better answer for your bathroom turns out to be a shower replacement in the footprint that already exists, that is worth hearing before the tub comes out.

Sources

Frequently Asked Questions

Do I need a permit to convert a tub to a shower in Baltimore County?

You do not need a residential bathroom alteration permit, but you do need plumbing and electrical permits. Baltimore County's Department of Permits, Approvals and Inspections states that an alteration permit is required for commercial bathrooms and not for residential ones, while plumbing and electrical permits are always required. The plumbing permit can only be applied for by a contractor holding a Baltimore County plumbing or gasfitting license, so it is pulled by the plumber, not by you. Other counties work differently. In Montgomery and Prince George's, the plumbing permit comes from WSSC Water and the plumber has to hold a WSSC license.

Can the shower use the existing tub drain location?

Sometimes, but usually not. A tub drain sits at one end of the alcove against the wall, and a shower drain needs to be where the pan slopes to, which is normally near the center or along one edge for a linear drain. Moving it means opening the floor. Two limits control where it can land: horizontal drain pipe two and a half inches or smaller has to fall at least a quarter inch per foot, and the trap has to stay within the allowed developed length of its vent, which is eight feet for a two inch trap at that slope. Beyond those, the joist layout decides the rest.

Is a curbless shower possible in any bathroom?

No. Curbless means the pan area has to drop roughly two to four inches below the surrounding floor so water runs inward. Over sawn lumber joists with depth to spare, that is usually done by sistering lower members or framing a recess, and notches are limited to one sixth of the joist depth, no longer than one third of the depth, and never in the middle third of the span. Over engineered I-joists or trusses, cutting and notching are prohibited unless the manufacturer allows it or an engineer signs off, so a true zero threshold may mean a framed recess or raising the rest of the floor. A low curb or ramped entry gets most of the benefit with far less structural work.

How big does the shower have to be?

The compartment has to enclose at least 900 square inches with no interior dimension less than thirty inches, measured at the height of the top of the threshold and carried up to at least seventy inches above the drain outlet, and the entry opening has to be at least twenty two inches of clear finished width. There is an alternative that allows a twenty five inch minimum dimension if the compartment holds at least 1,300 square inches. Thirty by thirty is the legal floor. Industry planning guidance recommends at least thirty six by thirty six, which is where you can raise your arms to wash your hair without hitting a wall.

Does the entire bathroom have to be gutted?

Not necessarily. Many conversions stay inside the existing alcove, which means the tub surround walls, the floor in the pan area and the plumbing behind the valve wall. The vanity, toilet and the rest of the floor can often stay. What forces a wider gut is a drain that has to travel, a vent that has to be reworked, a curbless pan that opens the subfloor, or opening the wall and finding rot or failed supply lines that should be replaced while they are reachable.

Is glass better than a curtain?

Glass contains the spray better and reads as finished work, and a curtain is cheaper and easier to replace. The practical catch with frameless glass is that the panel is cut to the opening and has almost no adjustment, so the walls have to be plumbed and furred during framing. In an older house with plaster over lath, that correction happens before the backer board goes on or not at all. Any glass in a shower enclosure with its bottom exposed edge less than sixty inches above a standing surface counts as a hazardous location and has to be safety glazing with a permanent manufacturer's designation.

Will removing the tub hurt my resale value?

It depends on how many tubs are left. Converting one of two or three bathrooms rarely registers with buyers. Converting the last tub in a three bedroom house aimed at families is a real objection you will hear from an agent, and converting the only bathroom in the house is the version to avoid. If you are planning to sell, convert the secondary bath and keep a tub somewhere in the house.

What should the contract show before I sign?

In Maryland, only a contractor licensed by the Maryland Home Improvement Commission may contract with a homeowner for home improvement work, and the contract has to carry the contractor's name, address, phone number and MHIC license number. It also has to include a notice with the Commission's phone number and website explaining that the Commission administers a Guaranty Fund that may compensate homeowners for certain actual losses. Anyone can check a license in the Commission's public search. Beyond that, make sure the scope names the waterproofing system, says who pulls the plumbing permit, and spells out how hidden conditions behind the wall are handled.

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