Demoing a cast iron tub

[M635_Guy]

We're buying a "new" house (built in 1986) next Wednesday, and the minute we close I'm going to start doing some demo stuff to the house. The highest-priority things are removing a pantry, a bar that is stuck inside a former closet (which is in a weird place anyway, we're just going to close it in entirely to a blank wall), remove a frat-house-style bar on the ground floor and, most-importantly remove a cast-iron tub on the ground floor to convert to a shower for my 83-yo mother-in-law.

I'm not worried about the any of those except the tub. I'm going to try to preserve the tile since I'd really rather not do the whole floor for both time and cost reasons. That rules out the sledgehammer approach, which seems a bit sketch anyway. My plumber told me to get some metal cutting discs for my grinder and take it out. My current plan is:

• Demo the current glass door and all the wall cladding around the tub and remove it.
• Cut anything holding the tub to the studs
• Use the angle grinder to cut a box around the drain, then a cut down the middle of the long side and two across the narrower side. If the tub doesn't look like it will gracefully come away from the tile, I'll probably make a horizontal cut down that length and see what I can figure out.
• Remove the pieces.

I'm not sure how heavy this is, and the room is a little tight, so six pieces vs. four seems like it will be worth the time. I'll use the corded Hercules grinder for cutting:


The questions:
I ordered some Makita metal cutoff wheels, as they seem to be the best mix of durable and fast-cutting. Anything better/faster? (I'd pay more if they work a lot faster)


I'm thinking about having my Milwaukee cordless grinder on hand with a flap disc to knock down anything that's super-sharp (I'm the guy that would hurt myself on an edge clearing it out), but not sure that's necessary. Thoughts?

I got the respirator below - 3MOV/AG P100 Pro Multi-Purpose Respirator. From what I can gather, this one will do particulates and fumes, but I don't see a lot definitive out there about what to use for this kind of job. It's a small room and there won't be a ton of ventilation. Any confirmations/suggestions under $100 appreciated!


I'll probably be doing this a second time for a bathroom upstairs, but that's a medium-term future. My MiL will need a shower she can use down there ASAP, so it's on the highest-priority list. Any thoughts/tips/etc. appreciated!

 

[Tunajoe]

Forget the respirator.
absolutely need a face shield.
those discs can break and cause real damage.
check out a few YT videos if you don’t believe me.

 

[slowtwitch73]

We have a ci tub that will someday be tossed out a window in pieces. Guy who does lots of remodels around here said a sledge is the way to go.

 

[Shiftless]

When I remodeled a bathroom in our house, it had a vintage 1950’s cast iron tub. I called a salvage company and they send 2 guys who took it out in one piece and handed me a check for $50. My old tub had one finished end. That no doubt made it more valuable than a standard model.
I did a sledge hammer demo of a toilet but never a CI tub.

I know guys who remodel bathrooms and they say use a sledge hammer on CI tubs.

 

[mike93lx]

I did a cast steel one a couple weeks ago.

Broke out the bottom with my jack hammer then cut it in half with carbide sawzall blades. Took two blades, but no risk of blowing up a cutoff wheel no real sparks and a lot quieter

The porcelain bits went everywhere, but I ended up with no cuts or injuries

I should have cut it into 3 or 4 pieces as it was still heavy as ****.

 

[tarmy]

I put an old blanket over it and beat it with a sledgehammer. Busted it up easily. It was on the second floor so I cut a hole in the floor and threw the chunks down there with everything else from the demo.

 

[MovingAlong]

Watch your sparks when grinding... old dusty wood is pretty flammable and you may throw sparks where you can't see getting started.

Trying to save the tile seems like false economy though. You've still got a foot and a half to replace at the bottom and a new pan to seal in and build from. Matching the tile is unlikely, matching the grout lines even less so. Waterproofing the cut line between old and new - I wouldn't want to try it.

In my experience, working from a fresh clean slate is quicker.

 

[M635_Guy]

Firstly, thanks for all the super-quick responses (and any more to come)! It's what makes this place great.

I have a face shield already (bought with the grinder).

I can't think of doing this without some filtration.

I don't want to risk the existing floor tile with the sledgehammer method. If I damage it, the money gets real in a hurry (my wife will then want to reno the whole area as the floor continues into the room with the vanity/toilet/etc.).

When I remodeled a bathroom in our house, it had a vintage 1950’s cast iron tub. I called a salvage company and they send 2 guys who took it out in one piece and handed me a check for $50. My old tub had one finished end. That no doubt made it more valuable than a standard model.
I did a sledge hammer demo of a toilet but never a CI tub.

I know guys who remodel bathrooms and they say use a sledge hammer on CI tubs.

I wish this were something of value, but like everything else in the bathrooms of this house it's valueless 80's stuff.

I did a cast steel one a couple weeks ago.

Broke out the bottom with my jack hammer then cut it in half with carbide sawzall blades. Took two blades, but no risk of blowing up a cutoff wheel no real sparks and a lot quieter

The porcelain bits went everywhere, but I ended up with no cuts or injuries

I should have cut it into 3 or 4 pieces as it was still heavy as ****.

I'm actually not sure if this thing is cast steel or iron, come to think of it.

I have the M12 Hackzall, and probably have some metal blades. That was already in my planned kit for the demo - I'll see if I have metal cutting blades, and will give them a try. Maybe I'll start the cuts with the grinder and complete them with the Hackzall. I don't have a full-size sawsall,

I see the corded Hercules is $99, but HD has the M18 for $129 right now...

 

[M635_Guy]

So it begs the additional question: with good blades, can the M12 Hackzall I already do it? Or should I pop for a full-size? (for the extra $30, I'd probably pop for the Milwaukee - this is exactly the kind of tool I hate cords for...).

I'll be doing other demo where I was planning to use the little guy. Not sure if it's enough to justify the bigger one if the existing grinder and Hackzall are up to the task of the tub, or how much I'd need it longer-term...

 

[M635_Guy]

Watch your sparks when grinding... old dusty wood is pretty flammable and you may throw sparks where you can't see getting started.

Fantastic tip - just added my fire extinguisher to the list.

Trying to save the tile seems like false economy though. You've still got a foot and a half to replace at the bottom and a new pan to seal in and build from. Matching the tile is unlikely, matching the grout lines even less so. Waterproofing the cut line between old and new - I wouldn't want to try it.

In my experience, working from a fresh clean slate is quicker.

I agree, but my plumber thinks he can get the new base in with the existing tile if I can preserve it. I have to try for both time and cost.

 

[Shiftless]

I appreciate your concern. If your wife wants to preserve the tile, then preserve the tile. Do you think that a layer of half inch plywood would be adequate protection for the floor? If you cut and fit plywood or OSB or particle board to fit, I don’t see how a broken piece of tub would damage the tiles underneath.
Or what about getting some scrap carpeting from a carpet store? Seems to me that you could get some old wall to wall carpeting that was coming out of a remodel job.

Sawing through cast iron seems to me like a losing proposition.

 

[mike93lx]

The m12 ain't getting it done if it is the brushed. Maybe fuel, but I can tell you that my Dewalt 20v brushless didn't enjoy it.

 

[rust in the eye]

You'll be deaf by the time you grind through that tub and broke from buying blades for a Sawzall. Cast iron is tough but brittle.
I've done this a few times. A BFH (minimum 10# sledge, 15# if you can swing it) heavy gloves and face/eye protection. Shards of porcelain glaze will be everywhere, including hair so perhaps a hat too. All you need to do is get it into manageable size chunks.

 

[M635_Guy]

I appreciate your concern. If your wife wants to preserve the tile, then preserve the tile. Do you think that a layer of half inch plywood would be adequate protection for the floor? If you cut and fit plywood or OSB or particle board to fit, I don’t see how a broken piece of tub would damage the tiles underneath.
Or what about getting some scrap carpeting from a carpet store? Seems to me that you could get some old wall to wall carpeting that was coming out of a remodel job.

Sawing through cast iron seems to me like a losing proposition.

I've seen YouTube videos of folks using a grinder, and it works pretty well. Slow-ish, but tidier and more precise than the sledgehammer method.

I'd already considered a piece of 1/4" plywood. I have some remnant carpet I'll toss in to take over there - great suggestion.

I can't eyeball everything again until just before closing, so I'm not sure how tight the base is to the tile.

The other consideration is the room is VERY tight - just the tub/shower combo and might not even be 36" wide beyond the tub. Not a lot of room to swing a sledge.

The m12 ain't getting it done if it is the brushed. Maybe fuel, but I can tell you that my Dewalt 20v brushless didn't enjoy it.

I've got the FUEL in the Hackzall.

Just noticing the M18 on $129 sale is the brushed boy and $199 for the M18 FUEL... Hmmm...

 

[RTM]

What about a small demo rotohammer (not a hammer drill) instead of the sledge or jackhammer?

And again the porcelain bits will go everywhere regardless of which method you use. Some will hurt .

 

[mike93lx]

I've got the FUEL in the Hackzall.

Just noticing the M18 on $129 sale is the brushed boy and $199 for the M18 FUEL... Hmmm...

Don't buy brushed.

 

[mike93lx]

What about a small demo rotohammer (not a hammer drill) instead of the sledge or jackhammer?

And again the porcelain bits will go everywhere regardless of which method you use. Some will hurt .

With how much work it took using a 50-60lb jackhammer, I think a little Sds is going to be miserable, plus putting your face a lot closer to flying sharp bits of porcelain

 

[dcg9381]

That grinder and those discs are what I'd use. +1 on the face shield comment. If you've never used that tool before, go slow, use little pressure.. It's usually getting it tilted and causing a bind or pushing it too fast that causes the disc to self destruct. I would buy at least 5 discs.

Definitely cut it out.. That's how I'd do it. No more "standard" tubs for me ever... If I can help it.

 

[steves_001]

Out of curiosity, what’s on the back side of the tub wall? If a room, open the wall, snip the studs ( if not load bearing) and kick the tub thru. Then sledge it over there. That leaves the tile as is. Odd that an 80’s house will be cast. Possibly just stamped steel. If it is it won’t be heavy.

 

[M635_Guy]

Out of curiosity, what’s on the back side of the tub wall? If a room, open the wall, snip the studs ( if not load bearing) and kick the tub thru. Then sledge it over there. That leaves the tile as is. Odd that an 80’s house will be cast. Possibly just stamped steel. If it is it won’t be heavy.

Unfortunately there's nowhere to go with it - Most of the room is below ground level, and in one of the front corners of the house. It's a tub with a metal surround and sliding doors - definitely not compatible with my 83yo MiL. Honestly, I can't remember exactly what the surround is, but pretty sure it's just basic tile. As I said above, I'll get everything off the walls, make sure the tub isn't attached to the studs in some way and then chop it up.

Since I have other demo to do in the house and some stuff to tame, I decided to take a hybrid approach. I'm going to use the grinder to box out the drain (after removing what I can), get some lines started with the grinder and then use a new toy I decided to add to the arsenal:

It was a fairly-decent price when bundled with a Forge battery ($299 for both vs. $199 each), which I've been meaning to pick up anyway. I haven't loved my Hackzall - pretty much my only Milwaukee tool I'm not very happy with - and that ******* above isn't going to ask any questions for the other stuff I'll use it for. And time is going to be important.

I'm pretty sure the tub I'm demoing was installed at the same time this one and is either identical or very similar (and same floor tile I think):

The one above has limited time left in the universe too, but I only have so much time, energy and (especially) $$. We might take our time and totally DIY that one. My wife has said she'd like to tile and she tends to be really good at stuff like this. I'll watch my buddy the plumber to see how much of this is over my head. I've got no problems paying the man for his skills if needed.

 

[pizza]

you should use:

• half-mask respirator (like in your pic) with P100 carts
• full face shield
• hearing protection (probably foam earplugs since the rest of the PPE is bulky)
• lennox metalmax cutoff disc. they last a long time. i'd think that one of them will get you through this job. also, they're much safer than normal cutoffs because they probably can't explode. they also kick up less dust into the air. a normal cutoff spits out abrasive and parts of the disc. the metalmax pretty much only kicks out the metal you remove from the workpiece. i was surprised to find that the room doesn't stink afterwards like with a normal cutoff. i love these discs!

here's the metalmax disc part numbers:


from the pic of your box, it looks like yours can take 4.5"–6"?
i guess you could try a 5" or a 6". they cut faster (bigger radius = higher speed) and should last longer (more circumference = more abrasive). idk

be sure to respect the max RPM of the disk also.

 

[Ultradog MN]

If it is cast iton, after you have tried all the ideas and used all the ineffective cutting tools that have been suggested, take an 8 lb sledge hammer and break it up.
Or break it up first and avoid all the expense and aggravation.

 

[mike93lx]

Out of curiosity, what’s on the back side of the tub wall? If a room, open the wall, snip the studs ( if not load bearing) and kick the tub thru. Then sledge it over there. That leaves the tile as is. Odd that an 80’s house will be cast. Possibly just stamped steel. If it is it won’t be heavy.

The one I just did was late 80's and was cast steel

 

[john.k]

A nice cast iron porcelain enamel tub sells for $100 here .........next door just sold one from their reno.

 

[mike93lx]

A nice cast iron porcelain enamel tub sells for $100 here .........next door just sold one from their reno.

$100 is at least an order of magnitude low to get me to haul one out of a house in one piece. No way

 

[john.k]

Yes ,a lot were pressed steel ,porcelain enamel .............in the 1970s ,I scrapped out a producer of pressed steel tubs ............they had 500 ton presses to blank out and press the tub shape .....and kilns to enamel them........cheap plastic tubs killed them ,because builders buy the tubs ,and they are cheap.

 

[rlitman]

...I ordered some Makita metal cutoff wheels, as they seem to be the best mix of durable and fast-cutting. Anything better/faster? (I'd pay more if they work a lot faster)
..
I'm thinking about having my Milwaukee cordless grinder on hand with a flap disc to knock down anything that's super-sharp (I'm the guy that would hurt myself on an edge clearing it out), but not sure that's necessary. Thoughts?
...
I got the respirator below - 3MOV/AG P100 Pro Multi-Purpose Respirator. From what I can gather, this one will do particulates and fumes, but I don't see a lot definitive out there about what to use for this kind of job. It's a small room and there won't be a ton of ventilation. Any confirmations/suggestions under $100 appreciated!...

1) Quality abrasive cutoff wheels are the fastest way to cut. I cannot speak to the quality of Makita wheels, but I'll say this about hardware store and tool brand cutoff wheels: they usually ****.
Several years before steel cutting diamond was a thing, a friend brought a stack of 10 DeWalt cutoff wheels to use on a project. He blew through all of them and only finished half of his cuts. I lent him a slightly used wheel of mine, and he finished the job with a little bit of it left to spare. I forget what it was, but it had to be a Norton or Sait or Walter or Pferd. I really haven't had luck with anyone else.

Nowadays I do 3/4 of my cutting using a diamond Lenox Metal Max. It's much safer, but cutting speed is not as good, and how poorly it performs depends a lot on what you're cutting. I'd say it runs about 90% as fast as a good abrasive wheel on mild steel, but that drops to 25% or worse on HSS. I have no idea how bad it would be on cast iron, but my guess is that it would be slow, because cast iron cuts easily, and diamond wheels are not aggressive.

As for sharp edges, yeah, I'd probably do the same, and yes, a flap wheel is your friend. Don't think about using a cutoff wheel for this.

One note about sparks. It was mentioned above that sparks can head into places unseen and start fires, but not mentioned is that the shower of sparks can ruin your tile. Cover the tile. Even a layer of rosin paper should be enough.

As for grinding dust, it's dust. You're not working with liquids, so there's no vapor to speak of. A plain P100 has much flatter filters than that crazy overkill mask, so it will fit much better under your face shield. An N95 should be sufficient too.

 

[M635_Guy]

you should use:

• half-mask respirator (like in your pic) with P100 carts
• full face shield
• hearing protection (probably foam earplugs since the rest of the PPE is bulky)
• lennox metalmax cutoff disc. they last a long time. i'd think that one of them will get you through this job. also, they're much safer than normal cutoffs because they probably can't explode. they also kick up less dust into the air. a normal cutoff spits out abrasive and parts of the disc. the metalmax pretty much only kicks out the metal you remove from the workpiece. i was surprised to find that the room doesn't stink afterwards like with a normal cutoff. i love these discs!

here's the metalmax disc part numbers:


from the pic of your box, it looks like yours can take 4.5"–6"?
i guess you could try a 5" or a 6". they cut faster (bigger radius = higher speed) and should last longer (more circumference = more abrasive). idk

be sure to respect the max RPM of the disk also.

Much appreciated! I'm all about the PPE. As a guy with hearing loss and tinnitus, I'm 100% on the hearing protection. I got a full-face shield when I got the grinder(s) and the respirator is NIOSH-approved OV/AG/P100.

What's your experience with the wheels in terms of speed? My impression of the diamond wheels is that they're really slow vs. their counterparts. I'm OK consuming the discs if it means I'm done significantly faster. I don't hate the idea of less stink though...

If it is cast iton, after you have tried all the ideas and used all the ineffective cutting tools that have been suggested, take an 8 lb sledge hammer and break it up.
Or break it up first and avoid all the expense and aggravation.

I'm not sure if you haven't read the thread, or are just ignoring what I've said are the requirements. I'm not doing the sledge as it risks the floor, which is a hell of a lot more expensive than any of the tools and consumables discussed. I needed the sawzall anyway, so this is essentially costing me the respirator, the blades and/or the wheels. I can live with that.

Also, the cutting tools will definitely not be ineffective. They'll take longer than the sledge, but I'm after a degree of precision and control the sledge just doesn't offer.

 

[pizza]

What's your experience with the wheels in terms of speed?

i've only used 5" on an angle grinder, and it didn't seem much slower. maybe even same cutting speed, idk. never used it on cast iron. only mild steel.

 

[pizza]

also i guess watch out for the tub collapsing and damaging the floor lol

 

[Ultradog MN]

I'm not sure if you haven't read the thread, or are just ignoring what I've said are the requirements. I'm not doing the sledge as it risks the floor, which is a hell of a lot more expensive than any of the tools and consumables discussed. I needed the sawzall anyway, so this is essentially costing me the respirator, the blades and/or the wheels. I can live with that.

Also, the cutting tools will definitely not be ineffective. They'll take longer than the sledge, but I'm after a degree of precision and control the sledge just doesn't offer.

I did read all the suggestions.
I was a contractor who primarily remodled bathrooms for 30 + years. Took out scores of tubs and did a dozen "Mother in law" refits so she doesn't have to lift her leg so high to shower in the tub.
Pour a concrete basin and tile it. Pour your basin so it overlaps the edge of the floor tile by about an inch.
But by all means...
Do as you wish.

 

[pizza]

and the respirator is NIOSH-approved OV/AG/P100

the only part of that you need is P100. i'd save those fancy carts for painting or something and just swap in P100s for this. i have not had very good experience with the disposable respirators like the N95s. i like that compliant rubber seal.

 

[M635_Guy]

I did read all the suggestions.
I was a contractor who primarily remodled bathrooms for 30 + years. Took out scores of tubs and did a dozen "Mother in law" refits so she doesn't have to lift her leg so high to shower in the tub.
Pour a concrete basin and tile it. Pour your basin so it overlaps the edge of the floor tile by about an inch.
Or...
Do as you wish.

With your experience, I'm sure you could demo the tub properly with a sledge without damaging the tile. Unfortunately, I haven't done any tubs, much less scores of them, so I'm controlling my risk. Simple as that. If I wasn't trying to preserve the floor, I'd use a sledge and this thread wouldn't exist. There's another one of these upstairs that I'll happily try a sledge on when the time comes.

My plumber is installing the base and tile. Having the damn thing ready ASAP is a priority.

 

[BlitzcrankJapan]

As has been mentioned, a sawzall will be faster and safer to demo a tub inside.
However they are more laborious than cutting discs.

 

[M635_Guy]

One note about sparks. It was mentioned above that sparks can head into places unseen and start fires, but not mentioned is that the shower of sparks can ruin your tile. Cover the tile. Even a layer of rosin paper should be enough.

Good point. I'd planned to cover the tile with floor paper and maybe some 1/4" plywood I have laying around

 

[Dagny]

Once you get a hole in it you will not believe how easy it breaks. But do what you want.

 

[Bert_]

It's a tub with a metal surround and sliding doors - definitely not compatible with my 83yo MiL.

Man I wish that line would work on my grandmother. She's 92 and any suggestion of putting in a shower gets shot down in a hurry. Same thing with a washer dryer on the main floor.

 

[Kurt4440]

I can see your dilemma and would be concerned that the sledge hammer vibrations would transfer to the floor and walls and would compromise the tile.
My initial thought would be to use a cut off saw. Rent, buy or borrow.

PPE to the max and ventilate the room.

 

[M635_Guy]

I can see your dilemma and would be concerned that the sledge hammer vibrations would transfer to the floor and walls and would compromise the tile.
My initial thought would be to use a cut off saw. Rent, buy or borrow.

PPE to the max and ventilate the room.

That's a bit of a big gun to bring to this fight, and not useful beyond this one tub. I think I'll stick to the grinder and sawzall.

 

[mike93lx]

That's a bit of a big gun to bring to this fight, and not useful beyond this one tub. I think I'll stick to the grinder and sawzall.

Shenanigans! Excuse for new tools