I would like to remove a bathtub, and replace with a shower stall. The tub is enormous-how do you remove it? Can you break them up with a sledge hammer?
Or is this a job best left to a pro?
It’s a lot of work. One way I’ve used: remove all the plumbing and the tile surrounds, cover with a heavy tarp, have at it with the heaviest sledge you can maneuver in your bathroom. The tarp keeps shards from flying around. Wear heavy, protective clothing, gloves, ear and eye protection, work boots.
There are other methods, including using sawzalls or trying to remove intact. I’ll let others talk about those methods.
Basically what I just said…
Is it a claw foot or a fancy type? You can get a few bucks for those and I would not destroy it.
If it’s just a plain old tub a fairly strong man can bust one up with a sledge but it’ll take a while.
It’s not all that technically difficult to remove it in one piece but it can be a royal pain in the ass. One problem is that they tend to be very heavy (300 lbs. or more), no way you’re carrying it out by yourself and even 2 people will find it quite difficult. Another is that they’re big which makes then unwieldy; trying to get one down the stairs and out the door, especially in an old house with tight staircases and hallways, can be an ordeal.
If you just want it gone and it’s not worth anything go ahead and go Hulk on it. It’s gonna be a mess, the chunks of iron can be sharp and the ceramic coating will fly off in shards so use goggles and gloves.
Make sure you’re very careful with the plumbing, you don’t want to crack any pipes.
If you’re pretty handy and willing to put in the time it’s doable.
If this sounds like too much of a pain hire a handyman/plumber.
Thanks…is there anything I could coat the tub with (to prevent the shards from flying around? maybe glue plastic sheets to it?
It sounds like an easy job-just worried about all those sharp shards flying around.
The link in the post by NoClueBoy says to drape a wet cloth or old towel over the tub and than whack it to hold the chips. I never tried it but it sounds like it’d work.
ETA: Actually that link is really good - go read it
Duct tape!
Also, you might consider calling your local piano moving companies to see if they’ll take the job, or know somebody who would.
if you get it out in one piece it can be used as a raised bed planter.
Even in my first post I said to lay a tarp over it. The wetting idea I found on the web page is a great add.
You might try stretch wrap, but those chips are sharp, and the force required to break up real cast iron is such as they WILL fly.
When I hired a plumber (only time it was not a DIY for pipes), it was for cast iron - the old tub and the stand pipe.
When they came over, they brought a young man with muscles where I didn’t know there were muscles - almost body-building muscular. He was in heavy construction canvas overalls, heavy boots, helmet and huge safety goggles - and a 20 pound sledge. We left him in the bath and went to the basement to discuss where what needed to go.
When, 20 minutes later, we came back, the (6’x 6’) room’s floor was covered to about 2" average, and the biggest piece was the size of a 5 pound bag of flour. The wall adjacent had nicks in it (the walls around were tiled)
Don’t skimp on safety! A chip of cast iron will likely go through your Home Depot goggles and clothing. Check out military surplus, maybe tool rentals.
Call a plumber and offer to pay them for a referral. If you have recently hired a plumber, he/they may well give you one.
“How much for the name of someone to bust up a cast iron tub?”
As other posters have already (correctly) pointed out, removing a (built in place) cast iron tub will be a serious task best relegated to a professional, for a couple of different reasons.
For one thing, a pro will (or should) have done this before and know exactly what to do, how to do it and have all of the necessary tools, second, any incidental damage incurred will be at his expense.
One small ‘tip’ if you decide to DIY, start breaking at an edge if possible, trying to hammer a ‘hole’ in a cast iron tub is way harder than breaking pieces off of it. Cast iron is a royal bitch to break up with a sledge hammer (been there, done that).
One more thing, scrap cast iron is worth money!
Scrap cast iron (if you decide to break it up) at the current price of +/- 12¢/lb., a 250 lb. tub would get you $30.00. 
Prices will vary from one scrap yard to the next, and also depending on where you are located, so call around first to get the best price. 
A complete tub can be worth even more at material recycle centers, especially if it’s an old ‘stand alone, claw foot’ type, as those are becoming popular again.
Finding a buyer might entail a little effort, but could be well worth the trouble. YMMV
Amateur DIYer, weekend warrior here.
About 5 years ago I gutted and remodeled our main bath. Existing tub was a built in cast iron job. I just laid a cloth painters tarp over it and went to town with a 20 lb. sledge. Jeans, t-shirt, gloves and goggles were it. Small room too 10’ x 5’, not lots of room for swinging.
Took me a couple hours. Wasn’t a big deal.
Edit to add - it was my first an only attempt to date at anything like it.
The thing is, getting a whole tub out and to the recycler is gonna be a major pita. Taking an hour to bust up one and haul the debris isn’t really worth $30 either imho. When we did the bathroom this past winter that was one of the bits we didn’t bother diy’ing. Less than 30 minutes of the sledgehammer wielding plumber’s apprentice and it was on the way out. Worth it I thought.
But then what will you do when someone attaches a bomb to your toilet?