Advice on corroded cast iron toilet flange on a powder room remodel

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Mr Blint

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1940s-era house with cast-iron waste pipes. The tongue-and-groove subfloor was in bad shape and has been removed. I plan to put down two layers of 3/4 plywood, isolation membrane, and tile.

As the pictures show, the toilet flange is corroded and the inside of the pipe is very pitted. I suspect that pitting on the inside wall would prevent one of the rubber-gasketed PVC flange inserts from making a good and tight seal against the pipe.

I've removed the wax and scrubbed the flange with a wire brush and mineral spirits. That's what that liquid is on the flange.

I would be very grateful for some expert advice on my Plan A, Plan B, and Plan C.
Thanks

Plan A
The flange is still solid, not crumbling. Reinforce the flange with metal "cleats". Then slather the flange with lots of plumbers paste and use a "Sani" style "springy" rubber-foam toilet gasket rather than a wax ring.
PROS: I am not likely to cause any major damage!
CONS: The plywood won't be underneath the flange, and the toilet's weight will be on the flange. It has been that way for decades already. Eventually the flange may begin to leak and I'll wish then that I'd done a more thorough job.

Plan B
Drill out the lead seal from around the toilet flange and try to remove the flange gingerly without damaging the waste pipe. Reinstall a new cast iron flange.
PROS: The plywood can go right up to the waste pipe so the flange can be screwed to plywood. This repair should be durable and last a good long time.
CONS: I've never done this. Never melted lead, don't have a torch or a little crucible or the caulking irons; I also don't know yet how to tell the difference between Xtra Heavy or Service Weight cast iron and might get an incompatible flange.

Plan C.
If I damage the waste pipe when trying to remove the old flange, I will then have to try to remove the section of cast-iron pipe either directly below the floor, or farther down in the basement, near where it enters the main waste pipe. We would either replace that section of pipe with the same thing, or if we remove farther down in the basement, we would transition from cast iron to 3" PVC.
PROS: The powder room waste is on its own small branch, so there is no weight of the cast iron from upper storeys resting on the section of pipe that would be cut out. I have also worked a lot with PVC and it should be fairly smooth sailing from that point on.
CONS: If I damage the cast iron hub in the basement when trying to remove that section of powder-room waste pipe, then I'm really up sh*t creek. :-(
I've never melted lead, don't have the torch and tools, etc etc.
I have to find out if a rubber donut-style gasket, which sits in the cast-iron hub, in order to make a transition to PVC, is up to code in Pennsylvania.
 

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Reach4

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Not a pro. So I would be thinking of ways that would be minimal. I might modify plan A a bit to fit wood under the flange as best you can. Then screw the flange into the wood if you can. What bothers me is there does not seem to be holes to allow you to screw the existing flange to the floor.

The surface might be fine with the Saniseal, but wax would conform to a more pitted surface than the Saniseal, I would think. Maybe the "plumber's paste" takes care of the pits and you can get the best of both ways. Had not heard of plumber's paste.

The flange does not carry the weight of the toilet; the floor does. The flange holds the toilet down and maybe laterally. Depending on things, perhaps you should put a repair ring in place that would take the vertical pull from the closet bolts. I don't know how far the top of the existing flange the new floor surface will be. What is the ID of that flange? You might be able to put a Sioux Chief 887-GPM atop the new floor with the seal fitting nicely into the existing flange.
 

Mr Blint

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Thanks for the suggestion. There are so many pipes in this area (copper domestic water, black-iron hydronic) that adding wood blocking that the flange could be bolted to is not really an option.

I looked at the Sioux Chief you suggested, which is the same principle as a couple of insert flanges with rubber gaskets that Oatey makes. One of them is a twist-in, and the other works with several adjustment screws that press the gasket against the inside of the waste pipe. I'm concerned about making a good seal inside the pitted waste pipe.

I also see that Oatey also has a "no caulk" cast-iron flange, but I don't know how it's installed.

http://www.oatey.com/brands/oatey/p...langes/closet-flanges/cast-iron-closet-flange

Can that flange be retrofitted onto the 4" waste pipe after the old flange has been removed? There's a very brief PDF, but I don't follow the instructions, which talk about punching a hole in a "metal stud". I have no idea what they're talking about.

http://www.oatey.com/doc/165_Cast_Iron_Flange.pdf
 

Reach4

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I don't know the answer to your question. Did you notice the question that I had asked, or did you think it not relevant because you will remove that flange?

Unless you have already decided to remove the existing flange, I suggest maybe drawing a side view sketch showing the flange, sub floor (the new plywood) and the projected flooring above that. It looks like the old flange is higher than your plywood, but it is not clear by how much. I was thinking you could screw the existing flange to the new plywood.

I have no experience taking cast iron apart, so my thinking was along the lines of keeping that and adding more. I don't know how the existing flange is attached to the offset fitting. I would think lead, but then I wonder how they would have gotten the lead in place. Others will have experience with that.
 

FullySprinklered

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Fitting to fitting to fitting to fitting. Mr Blint, you're way totally screwed beyond belief.

I do see one possibility. Not being there is not helpful, but that last fitting before the flange has a mighty long straight section in it. See if it's possible to sawsall that fitting and "fernco" a 45 or street 45 in there and bring it up into a new toilet flange. Looks like Captain Miles Standish might have personally left some dna in there, so you might get some kind of government grant to cover your expenses.
 

Gary Swart

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To my untrained eye, that looks like a Rube Goldberg invention. I know you want to DIY, but sometimes the best of us have to resort to biting the bullet and call a pro.
 

hj

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Plan E. take a cold chisel and place inside the flange at the two sides next to the slots, then hit it with a hammer a couple of times and it will split in two so you can just pull it off. Then use the chisel to slice down through the lead and take it off also. AFTER you install the floor, to a plumbing store and buy a strand of oakum. Push it into the "groove" with a big screwdriver, get a large soup ladle, cut the lead you removed into small pieces and put them in the ladle. Heat the ladle with a torch until the lead melts then pour it over the oakum. Repeat until the groove is filled, then use a hammer to "calk"the lead using that same bit screwdriver. Job done.
 

Mr Blint

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I've sent some scrapings off to the lab to see if there's any colonial-era DNA in there that would qualify me for a government grant. Thank you, fullysprinklered, for bringing that to my attention. Fitting after fitting after fitting is right.

I actually started taking the flange off yesterday afternoon before I saw HJ's Plan E, after watching some YouTube videos. I tried to be careful and patient, in case that flange had to be put back for some reason. I drilled out the lead around the entire perimeter, and then tapped the flange clockwise/counterclockwise, back and forth, back and forth, until it started to rotate fairly freely, and then it lifted out .

You can see from this new picture how badly corroded the pipe inside the flange is. I didn't cause that damage. It was already there. So that length of pipe has to come out of the hub.

Is it possible to buy cast iron pipe pre-cut to a specific length? Do plumbing stores provide that service?

I've also ordered one of these:

http://www.oatey.com/doc/165_Cast_Iron_Flange.pdf

The Directions For Use seem to be for a different product:

DIRECTIONS FOR USE Punch 1-3/8” hole in metal stud. Snap clamp into hole. Clamp is offset to allow for adjustment of centers from stud to stud. ½” clamp allows for ¼” and 3/8” tubing installation through secondary holes in clamp. Check with local codes to ensure proper spacing requirements for piping support.


You can see in the picture how the hub is also a little higher than the floor joists. The bottom layer of plywood will have a bigger hole to accommodate the hub, but the top layer will be closer to the flange, and there should be 3/4" of plywood to screw the flange to.
 

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hj

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there is NOTHING wrong with that pipe, if it is long enough for the flange's gasket seal to fit it. The instructions are for something to hold a water line in a steel stud.
 

Mr Blint

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there is NOTHING wrong with that pipe, if it is long enough for the flange's gasket seal to fit it. The instructions are for something to hold a water line in a steel stud.

Well, HJ, I wasn't sure if it was long enough for the flange's gasket seal to fit, so I spent the afternoon removing it.

I hope there are two options open to me at this point:

1) get a Schedule 40 XH pipe in the right length and lead-and-oakum caulk it in place or
2) use a length of PVC and caulk it in place with Oatey Sta Put or something similar.
 

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Cacher_Chick

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I have not done it, but the commercial plumbers here commonly lead and oakum PVC into cast iron. The local code requires cast iron below grade, and then they transition to PVC for the above-grade work.
 

hj

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I have never tried to "lead/oakum" a piece of plastic into a cast iron hub. The heat would soften the plastic and since it is a "soft" material, calking the lead might just squeeze it rather than seal the lead to the joint.
 

Jadnashua

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It doesn't seem to be used much, but at least one company makes a sealant designed to replace the lead/oakum sealed joint. YOu still use the oakum, but then caulk in the sealant. then, some more oakum, more sealant. I had planned to try this on one joint, but after calling all over town (Rochester, NY, maybe a million people in the county), only one place had it, and when I finally got it home, checked the date code, found it was 10-years old, and hard as a rock when I tried to use it. IOW, it doesn't appear to be very common, but does meet codes when installed properly with fresh material. Actually, I had someone pick it up for me, otherwise, I may have noticed it was way out of date. Ended up cutting out the CI and rebuilding with pvc...I didnt' have the tools or skills to do a horizontal lead joint up tight against a plaster ceiling.
 

FullySprinklered

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I have never tried to "lead/oakum" a piece of plastic into a cast iron hub. The heat would soften the plastic and since it is a "soft" material, calking the lead might just squeeze it rather than seal the lead to the joint.
I've only done it twice, residentially; couple of shower drains provided by a customer who's not from this country. Works just fine , the lead cools quickly, no leaks.
Excuse me. I reread the posts and the reference was to leading in PVC to an iron hub. No, I've never done that, but I've done service sinks and a couple of shower drains. I've done less than ten leaded joints ever.
 
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Asktom

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I have leaded in ABS and it works fine. I never tried PVC.

You can melt lead in an old pan on the stove (exhaust fan recommended). Don't cook in that pan after that.

For a novice, I would suggest using oakum and Black Swan Soil-O - it also works fine.
 

Mr Blint

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I've seen the cans of the chemical-compound lead substitutes that are used with oakum for sealing PVC in a cast iron hub. But it's hard to find out whether it is to-code here in PA, where things are very old-school. If it's to-code, it might become my plan A, because finding a short piece of 4" cast-iron pipe isn't easy. It's sold around here in 10-foot lengths, minimum, for $140. I'd have no way of transporting it, let alone the cost. Lowes advertises 5-foot lengths for around $70, but not in my area of the country.
 

Asktom

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It is quite possible (likely) that Soil-O is not listed (approved), but, approved is actually what the inspector says is OK - so, ask. There are other brands, but this is the one I know and I know it works. It has been around for a bazillion years. so the old fashioned inspector may be familiar with it.

If you never poured a joint before you can probably do a better job with a soil cement.

The ring in your picture is a 4x2 ring, they make them deeper (4x4, 4x6) so you don't need to buy pipe. You can get longer ones in both instant-set and caulk styles.

I am not a big fan of instant-set style rings because you need to cut a larger hole in the subfloor and that can compromise your ability to fasten the ring to the floor because the screw hole is near the edge of the cut. If the screws don't hold then the toilet is held to the floor by the ring, and they can pull loose in that case.
 
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