When it's time to install a new bathtub, it's also time to remove the old tub. Removal of a heavy, bulky cast iron tub isn't like removing an acrylic or fiberglass tub. Weight, bulkiness, and the possibility of damaging your walls and floors are formidable challenges.
But you've got three methods you can choose from that simplify removal and speed your way to the important task of remodeling your bathroom. You can either remove the cast iron bathtub in one piece or you have two options for breaking it up into small pieces. The solution depends on your needs and abilities.
Before You Begin
If you need to keep the tub for some reason—for example, to reuse it in another part of the house or to sell it—you can try to remove it intact. It's not necessary to keep the tub in one piece for private debris haulers, as they take debris in nearly any condition.
Lighter-weight modern freestanding cast iron clawfoot tubs weigh 250 to 300 pounds. Modern rolltop cast iron tubs can weigh 350 to 400 pounds. Some older cast iron bathtubs weigh 400 pounds or more.
The weight of cast iron bathtubs alone may prevent single-piece removal. Breaking up the tub with a sledgehammer makes it easier to remove since pieces are just a few pounds or less. Cutting up the bathtub with an angle grinder reduces carrying weight to 125 to 200 pounds per piece.
Modern freestanding clawfoot tubs are about 66 inches long, 36 inches wide, and 25 inches high. Slipper tubs raise the height another 6 inches, to 31 inches high. Standard alcove cast iron tubs are 60 inches long, 30 to 34 inches wide, and 20 to 22 inches high.
With most interior doorways ranging from 28 to 32 inches, moving intact bathtubs through doorways can be difficult. Doors and door casing can be removed to provide greater accessibility. Claw feet usually can be removed.
Remove Tub Intact
Less hazardous debris
Difficult to get through doors
Requires several helpers
Removing the cast iron tub intact means detaching the tub from the walls and floor, and moving it in one piece out of the bathroom through the door.
Mess is kept to a minimum and the possibility of injury from sharp metal is reduced.
Yet alcove bathtubs tend to fit so snugly in their bays that something has to give—either the walls or the tub. With this method, you may need to remove or shave down a wall stud or two to swing the tub out.
With free-standing cast-iron tubs, carrying it out intact is the best way to go, unless doorway limitations preclude this.
Break up Tub With Sledgehammer
Easy removal of debris
Reduces tub to small pieces
Sharp, dangerous pieces
May damage floor, walls
In this method, the cast-iron bathtub stays in place while taps from a sledgehammer methodically chip away the tub, so it can be removed in smaller pieces.
Breaking up the cast-iron bathtub with a sledgehammer is the preferred method for contractors and do-it-yourselfers alike. The tub can be reduced to pieces small enough to fit in contractor plastic bags.
You'll need heavy gloves for this one, as the metal shards and chips of porcelain coating are razor-sharp. The sound is deafening, so hearing protection is required.
If you can handle the temporary mess, using a sledgehammer is the fastest way to break up and remove a cast iron tub.
Cut up Tub With Angle Grinder
Relatively little mess
Fewer pieces of debris
Sharp metal kept to minimum
Dulls blades quickly
An angle grinder fitted with a metal-cutting blade can cut through a metal bathtub, halving it for easier removal from the alcove and out of the bathroom. Because cutting is difficult, it's best to simply cut the tub once, either widthwise or lengthwise. Cutting it into many pieces takes too long.
The angle grinder produces glowing-hot metal shavings, but overall it's a fairly clean operation. Unlike the thousands of sharp metal pieces with the sledgehammer method, you only have two to deal with here. The tub's thick metal dulls blades quickly, and the job is extremely loud and requires patience and time. Plus, the two resulting pieces are still heavy—just not as incredibly heavy as a full-size tub.
When to Remove a Cast Iron Tub
When bathroom remodeling, remove alcove cast iron tubs after the tub's wall surround has been removed. This gives you access to any screws or nails on the tub's upper flange. Typically, the wall surround rests over the flange.
Since removing a cast iron tub is so messy and may damage the bathroom walls and floor, do this project before any finish surfaces are installed.
Wear safety glasses when removing the tub. When using the sledgehammer or angle grinder, wear hearing protection.
Protect yourself from the sharp metal with leather or other thick gloves, long sleeves, pants, and work boots.
When removing an intact cast iron tub, weight and bulkiness make this a job not just for two strong people but as many as three or even four.
Equipment / Tools
- Drain plug wrench
- 10-pound sledgehammer
- Appliance dolly
- Angle grinder
- Wrench set
- Caulk removing tool
- Cordless drill
- Leather gloves
- Safety glasses
- Hearing protection
- 1/4-inch plywood or luan, 4-foot by 8-foot
- Contractor clean-up bags
- Contractor flooring paper
- Metal angle grinder cut-off wheels, set
Prepare Bathroom and Bathtub (All Methods)
Shut off Water
Shut off water to the bathtub either at an intermediate valve located nearby or at the main water shut-off. Shutting off water using the bathtub faucet is not sufficient.
Seal off Bathroom
For breaking up the tub with a sledgehammer or using an angle grinder, seal off entrances to the bathroom with plastic sheeting.
If the bathroom flooring will be replaced or if this is subflooring, there is no need to protect the flooring. Otherwise, add 1/4-inch plywood or luan to protect the flooring near the tub. Lay heavy-duty flooring paper on hallways leading to the outside.
Remove the tub faucet, handles, and overflow with a screwdriver and wrench.
Remove the tub drain by first removing the screen with a screwdriver, then using the plug wrench to turn out the drain counter-clockwise.
For alcove tubs, use a caulk removing tool or screwdriver to remove caulk between the top of the tub and the bottom of the tub surround.
Remove Tub Surround
For alcove tubs, demolish the tile tub surround or pull back and remove a plastic tub surround.
Remove Tub Intact
Slide Tub Directly Out
After the attachment points have been removed, you can slide a tub directly out of the alcove if you have no obstructions such as drywall, a toilet, or bathroom vanity.
Tilt to Side
With a couple of assistants, tilt the tub on its side. Be careful, as the tub will be weighted toward the side of the tub floor and will want to tilt back in that direction.
Remove Claw Feet (Claw Foot Tubs Only)
While assistants hold the tub in place, use the wrench set to remove the claw feet from a clawfoot tub.
Place the tub on the appliance dolly. Rotate the tub so it will exit the bathroom door lengthwise.
Break up Tub With Sledgehammer
Double up a few contractor bags and set them nearby. Attach sheet plastic to the door.
Wear safety goggles, breathing protection, hearing protection, long sleeves and pants, and work boots.
Strike Bathtub Apron
Start by striking large areas that are unsupported in the back such as the front apron. Once you have created an opening, remove that debris. Continue to chip away at the rest of the apron.
Strike Inside of Tub
Standing in the tub or with one foot in the tub, strike around the walls of the tub. Start at the front of the tub. Then, work on the back long wall and finish with the front and back sections.
Break Tub Deck
If some of the tub deck remains, strike these areas from the top-down.
Cut up Tub With Angle Grinder
Fit Grinder With Metal Wheel
Add the metal grinding cut-off wheel to the angle grinder.
Remove any easily flammable materials. Have an assistant nearby to watch for sparks and fire as you grind.
Cutting a metal bathtub in a small, enclosed space is extremely loud. It helps to wear muff-style hearing protection for this job.
Cut Down Center
Cut the bathtub in half (widthwise, not lengthwise). So, a 60-inch-long tub would be cut into two 30-inch pieces.
Draw Two Pieces Together
Use the prybar to jostle one half of the tub up and toward the other half. Remove it, then follow by removing the second half.
Troubleshoot Removing a Cast Iron Tub
Intact tub is still caught in the alcove.
Another tactic is to remove three wall studs from the foot end of the tub, remove the drywall on the other side of the wall, and then slide the tub out lengthwise into the adjacent room.
The tub is stuck to the floor.
Installers often set bathtubs in beds of mortar to provide a stable base for the bathtub. If all other attachment points are released, yet the tub will not move, it may be stuck to the floor with mortar.
If you're trying to remove the tub intact, you may need to switch gears and instead break it up. This helps you remove the tub floor plus mortar as one piece.
When to Call a Professional
Contact a general contractor for help with removing the cast iron tub if you're not strong enough to lift 100 to 200 pounds, cannot swing a 10-pound sledgehammer, or cannot safely operate an angle grinder. You'll need to have a rolloff dumpster, arrange for a private debris hauler to pick up the tub, or have the contractor take care of disposal.