Turning an old tub into a walk-in shower

October 2026

Most tub-to-shower conversions start because someone in the house is tired of stepping over a tub wall every morning. The finished shower is the easy part to picture. What decides whether it holds up is the work you never see: the floor, the drain and the waterproofing behind the tile.

Taking the tub out and seeing what is under it

Before any of it, think about the rest of the house. If this is the only tub you have, losing it matters to anyone bathing small children and to some buyers later on. Plenty of owners convert the primary bath and keep a tub in the hall bath. That is your call, and it is worth making on purpose.

Once it is settled, a conversion starts as demolition. The old tub comes out, often in pieces if it is cast iron, along with the tile or surround and the wallboard or plaster behind it. We protect the route through the house first. Floors get covered and the doorway gets closed off with plastic, and the path to the truck stays off your good rugs. Bathroom demo makes fine dust, and a house with plaster walls makes a lot of it.

If your house was built before 1978, painted surfaces may contain lead, and the work follows lead-safe practices under the EPA renovation rule. That changes how the room is contained and cleaned, and how debris leaves the house. It is not something we skip because a wall looks clean.

The real value of demo is what it shows. Behind an old tub you can find rot at the bottom of the studs where an edge leaked for years, or a subfloor gone soft around the old drain. Old wiring turns up too, and knob-and-tube still appears in older Massachusetts homes. When we find something, you hear about it that day, with photos and a plain explanation of what it means for the job. Steve started this company after years of working for builders who did not keep their customers informed, and a surprise behind a wall is exactly where that matters most.

Checking the floor and the framing before anything new goes in

A tub spreads its weight over a wide footprint. A tiled shower puts mortar, tile, glass and a standing person on a smaller area, and tile cracks when the structure under it flexes. So once the room is open we look at the joists: their size and span, whether a plumber decades ago notched them to fit the old drain, and whether the subfloor is solid plywood or old boards with gaps between them.

Older New England houses have their own habits. Balloon framing in an older colonial or Victorian means wall cavities that can run from the basement toward the attic, which matters for fire blocking and for where pipes can travel. A Cape may tuck the bathroom under a sloped ceiling, which limits where a shower head and a glass panel can go. Ranches and split-levels tend to be simpler, though not always.

Repairs at this stage are ordinary work. A notched joist gets sistered, a rotted section of subfloor gets replaced, blocking goes into the walls. Blocking is worth planning even if nobody in the house needs grab bars today. Solid wood behind the tile where a bar might go later is a small addition now, and it saves tearing out finished tile years from now.

If widening the opening touches a wall that carries a load, we will tell you before anyone swings a hammer, and we will tell you what changes because of it.

Where the drain goes, and how the floor gets to it

This is the part most people never think about. A tub drain sits at one end of the tub, close to the wall, and it is often a smaller line than a shower wants. A shower drain usually moves: toward the middle of the floor for a traditional square or round drain, or to the back wall for a linear drain.

Moving a drain means opening the floor and rerouting the line to the stack with the right trap and venting. A licensed plumber does that work, as Massachusetts requires, and the rough plumbing is inspected before it gets covered. Over an unfinished basement the plumber can usually work from below. On a second floor above a finished ceiling, part of that ceiling may have to come down, and we would rather you hear that at the walkthrough than on the day the plumber arrives.

Then the floor has to slope to the drain. The usual target is about a quarter inch per foot, enough that water runs off without the floor feeling tilted underfoot. With a center drain the floor pitches in four directions toward one point. With a linear drain it pitches in a single plane toward the wall, which makes larger floor tile easier and suits a curbless entry.

The valve deserves its own decision. The tub valve is usually replaced in a conversion, because the shower head moves up, a handheld often gets added, and an older valve may not have the pressure balancing a newer one does. Where the valve, the head and any handheld sit is settled before the walls close.

Waterproofing is the layer you never see

Tile and grout are not waterproof. Water works through grout lines, and what keeps it out of the framing is the layer behind the tile. Older showers relied on a mortar bed over a liner and a fair amount of luck. The common approaches now are a sheet membrane bonded over the backer board or a liquid membrane rolled on in coats to a set thickness. Either one ties into the drain, so water that gets under the tile goes down the drain instead of into the floor.

The details matter more than the product name on the bucket. Inside corners, seams between boards, every screw head, the valve and the shower arm each get their own treatment. A niche is a box cut into the wall that has to be sealed on all five sides, with its bottom pitched slightly so water does not sit there. A bench seat gets the same care.

Before any tile goes down, the pan gets a flood test. We plug the drain, fill the shower floor with water and leave it to see whether the level drops. It is a simple test, and it is the last chance to find a leak while it is still easy to fix. We can show you the membrane and the test before tile covers them, so you know what is behind your walls.

Curbed or curbless, and what each one asks of the floor

A curbed shower has a low wall at the entry that keeps the water in. It is the simpler build. The shower floor can sit a little higher than the bathroom floor, and all the slope happens inside the curb. In a lot of older houses it is the practical choice.

A curbless shower has no step at all. The bathroom floor runs straight into the shower, which looks clean and is easier for anyone using a walker or planning to stay in the house as they get older. The catch is the floor. For water to stay in the shower, the shower floor has to sit lower than the floor beside it. That usually means recessing the subfloor between the joists, sometimes reworking the joists themselves, and running a linear drain along the back wall.

That work is very possible in many houses and impractical in some. The direction and depth of the joists decide it, along with whatever sits below the bathroom. We will tell you which one your floor supports once we have looked at it, and if curbless means more structural work than the room justifies, we will say so plainly. A low beveled curb is a sensible middle ground for some owners.

The choice affects the glass too. With no curb to catch spray, a curbless shower usually wants a longer wet area or a larger panel so water stays where it belongs.

Picking tile that behaves on a shower floor

Wall tile and floor tile do different jobs. On the walls you can run large porcelain with few grout lines, which is easier to keep clean. On the floor, a center drain calls for small tile, usually two inches or a mosaic, because large flat tiles cannot follow a floor that pitches four ways. A linear drain lets the floor tile go larger because the slope only runs one way.

Grip matters on a wet floor more than anywhere else in the house. Smaller tile with more grout lines gives your feet more to hold, and many porcelain tiles are rated for wet floors. Polished marble photographs well and can be slick underfoot once it is wet.

Natural stone works in a shower, and it asks more of you afterward. It needs sealing and gentler cleaners, and over time it can darken or etch where water sits. Porcelain asks almost nothing. Neither choice is wrong. We would rather you pick knowing which one you are signing up for.

Layout is where custom tile work shows. We plan it so cuts land in corners rather than at eye level, the niche lines up with the grout joints, and the tile around the valve is cut clean instead of hidden behind an oversized trim plate. Those are the things people notice in a finished shower without being able to name them.

Glass gets measured after the tile is set

Shower glass is cut to the finished opening, so it is measured once the tile is done, not from the plans. That leaves a gap between tile and glass, and knowing it is coming keeps it from feeling like a delay. Depending on the layout, the shower can often be used with a temporary curtain in the meantime.

A single fixed panel with no door is the simplest setup and suits a walk-in layout with enough room behind it. A panel with a hinged door closes the shower in and holds more heat. Heavy frameless glass needs solid backing in the wall where hinges and clamps go, which is one more reason the framing gets planned early. Shower glass is tempered safety glass, and the hardware needs proper clearance from the tile.

The fan, the permit and the final walkthrough

A tub often gets used for an occasional bath. A walk-in shower runs hot water every morning, so the exhaust fan matters more than it did before. Plenty of older bathrooms have no fan, or one that blows straight into the attic. Warm wet air in a cold Massachusetts attic condenses on the roof boards, feeds mold and adds to the heat loss behind ice dams. A proper fan is sized to the room and ducted with insulated duct to the outside. A licensed electrician wires it, and a timer or humidity switch keeps it running long enough to clear the room. In towns that have adopted the stretch energy code, the work follows it.

A conversion that moves plumbing is permitted work. The permit runs through your town or city building department under the state building code, 780 CMR, and the plumbing and electrical permits come from the licensed trades doing that work. Inspections typically happen before the walls and floor are closed and again at the end. Steve holds an unrestricted Massachusetts Construction Supervisor License, and the inspector's visits are scheduled into the job, not squeezed around it.

Everything above goes into a written scope before work starts, including what we will do if demo turns up rot or old wiring. You deal with Steve, you get updates as the job moves, and changes are talked through before they happen. The work area is cleaned up at the end of each day. One customer put it this way: "If its not right; Steve wont put his name on it!" If you are thinking about taking out a tub, call us at (781) 974-4263 and we will come look at the room with you.