Bathtub Replacement

A bathtub gets replaced for a handful of reasons: it is chipped or cracked, the finish has worn through and been refinished once already, it is a color that dates the whole room, or there is a leak. Whichever it is, the work extends beyond the tub itself, because a tub is built into a waterproof assembly rather than dropped into a hole.

Why the surround comes with it

An alcove tub has a flange around its top edge that the wall covering laps over. That is what stops water running down behind the tub. To remove the tub, the bottom courses of tile have to come off, and once you are into the tile there is no clean way to stop.

Matching an existing tile, especially one from the 1960s or 1990s, is realistically not going to happen. And a mismatch at the bottom three rows is the most visible place it could possibly be. So a tub replacement is normally a tub, a surround and a valve.

That is not a contractor upselling. It is what the assembly requires. Anyone quoting a tub swap with the tile untouched is either not removing the flange properly or is planning a repair you will not like.

Removing the old one

Cast iron is the usual find in houses built before the 1960s, and around here that is a lot of houses. A cast iron alcove tub weighs 300 to 500 pounds. In a house with a turn in the staircase it is not coming out in one piece. Standard practice is to cover it, score it and break it up with a sledge, then carry out the pieces. It is loud for about twenty minutes and it is far safer than four people trying to negotiate a staircase.

Steel and acrylic tubs come out whole and are straightforward.

Once it is out, the alcove is exposed. This is where we usually learn something: rotted subfloor at the tub apron, wet or crumbling plaster on the back wall, framing that has taken water, or galvanized supply piping that is closing up. All of it is normal for the age of the housing and all of it is easier to deal with now.

Choosing the new tub

Material

Acrylic is the most common choice. Light enough for one person to carry, warm to the touch, holds heat reasonably and comes in the widest range of shapes. The surface scratches more easily than porcelain, and most scratches can be polished out.

Porcelain-enameled steel is inexpensive and has a hard, durable surface. It is cold to sit in until the water warms it and it is noisy when filling. In a secondary bathroom or a rental it is entirely sensible.

Cast iron holds heat far better than anything else, feels substantial, and lasts effectively forever. The weight is the consideration: a filled cast iron tub on an upper floor in an older house with undersized joists sometimes needs the framing checked and occasionally reinforced.

Configuration

Alcove tubs fit between three walls with one finished apron. This is what the vast majority of bathrooms in this area have, and a standard alcove is about 60 inches long by 30 to 32 deep.

Drop-in tubs sit in a built deck, which needs framing and a finished surround and takes considerably more space.

Freestanding tubs are a design statement and need a large room. They also need the plumbing brought up through the floor or wall in exactly the right position, and floor-mounted filler plumbing is fixed before the floor closes.

The drain end matters and gets missed. A tub is left-hand or right-hand drain, and ordering the wrong one means either moving the plumbing or returning the tub.

The valve

With the wall open, the valve gets replaced. Current requirements call for pressure-balancing or thermostatic protection in tub-shower valves, which prevents the temperature spike when a toilet flushes elsewhere in the house. An old two-handle valve has no such protection.

The tub spout, the diverter and the shower arm all connect to that valve, and they are set at fixed heights during rough-in, so the fixture selection has to be settled before the wall closes.

The new surround

Two routes.

Tile over cement backer board with a waterproof membrane. More labor, better looking, and it lets you take the wall to whatever height you want, to the ceiling generally looks considerably better than stopping at six feet, and is only marginally more work. Waterproofing detail is exactly as described on the shower remodeling page.

Solid surface or acrylic panels in three pieces, sealed at the corners. Fewer joints to maintain, quicker to install, less expensive. They look like what they are, and in a secondary bathroom that is often a perfectly reasonable trade.

Either way, this is the moment to add a niche if you want one, and to put solid blocking in the walls for a future grab bar. Both cost almost nothing while the wall is open and are a demolition later.

Sequence

1. Protection down, water off.
2. Tile and surround removed, tub removed.
3. Inspect and repair framing and subfloor.
4. Rough plumbing: valve, supply, drain and overflow, then inspection.
5. Tub set level and supported per the manufacturer, acrylic tubs need a mortar bed or the specified support, or they flex underfoot.
6. Backer board and waterproofing over the flange.
7. Tile or panels, then grout and cure.
8. Fixtures, sealant at the tub-to-tile joint, final inspection.

That last sealant joint is not a small detail. The tub moves when it is filled and empties, so the joint between tub and tile is a movement joint and takes flexible sealant, never grout.

What drives the cost

• Tub material. Steel to cast iron is a wide spread.
• Surround choice, tile versus panels, and tile height.
• Hidden damage behind the old surround.
• Valve and fixtures.
• Removal difficulty, particularly cast iron on an upper floor.
• Supply line replacement if galvanized piping is found.
• Framing reinforcement where a heavy tub needs it.

Related work

If you are undecided about keeping a tub at all, see tub-to-shower conversion. If the whole room is dated, full bathroom remodeling is often better value than doing this in isolation.

Tub replacement across our service area

Cast iron tubs are the norm in the prewar housing of Maplewood, Montclair and Newark, and steel or acrylic in postwar Union and Livingston. See all service areas or return to bathroom remodeling.

Every town has its own bathroom remodeling page covering the housing there and what it means for a project. See the full service area.