Toilet Flange

[diva]

I recently bought a very much fixer upper. When I removed the toilet, and threw it in the dumpster, I discovered a very bad leak that had gone on for quite some time. The floor, joist etc are all either good, or replaced, but the flange is all rusted and corroded. This is on the cast iron 4" pipes, or course. What is the best course of action? Can I just cut the pipe back close to where it enters the house and install the PVC and go from there, or do I have to stick with a cast iron soil stack and flange? If so, how the heck do I get the old one off? P.S I love this site! Thanks for all the info!!!

[LazyPup]

IF the flange is just rusted and corroded that is normal for an old cast iron flange and is really not a problem. Just chip the worst of the rust off the mating surface with a stiff putty knife or 5 way painters tool then brush it up as clean as you can with a wire brush. Cast iron is normally sort of pitted looking but the wax ring will compensate for that.

Quite often we find old cast iron flanges that have a portion of the screw slot broken off. Rather than replace the flange you can install a repair flange which fits directly under the lip of the old flange and it bolted in place.

If you elect to remove the cast iron flange you can replace it with PVC. There are numerous methods of attaching the new PVC to the old cast iron.

1. You can cut the cast iron with a "cast iron Snap cutter" to get a smooth end, then attach the new PVC to the old cast iron with a PVC x CI (CI= cast iron) rubber Fernco coupling.

NOTE: You can usually rent a cast iron snap cutter from a local tool rental company for about $15 to $20 for a day. Cutting the cast iron with a snap cutter will take about 5 minutes and will make a perfect cut. It can be done with a sawzall but usually will take about 45 minutes to an hour and will use 5 or 6 blades which cost $4 each, so in the end renting the snap cutter will prove the most economical solution.

Cast iron pipe is super strong but a very brittle metal. You can easily break out a section of cast iron with two 2LB hanmmers.


CAUTION: before cutting or breaking out a section of cast iron, espeically when working on vertical stacks, make sure the pipe above the point of the cut is well supported by hangers or blocking and bracing. When in doubt take the time to install additional strap hangers to support the upper section. Failure to do this can and often will result in the piping above the point of cut falling down, which may cause serious property damage and/or personal injury.

Hold one hammer tight against the pipe wall on one side and rap the pipe on the opposite side with the second hammer. The cast iron will shatter. Once you have it shattered out you can continue breaking it out until you get to a hub on the downstream end of the section your are removing. Once you have the cast iron broken out, drill three or four holes close together in the lead to get a starting point, then insert a pry tool into the holes and pry the old lead out, then clean the oakum out (Oakum looks like frayed hemp rope).

Fernco makes a rubber donut gasket that can be used to seal the new PVC into the cast iron hub or you can insert the PVC into the hub, pack the hub half full of Oakum and top it off with plumbers epoxy.

[diva]

Wow! thanks a bunch! that was a perfect answer for me. The flange is "super rusted" and one of the bolt slots is missing and/or broken. I did not know that they made such a thing as a repair flange. That has got to be easier than removing all the cast iron. I am going to try that this weekend. I really had been losing sleep over this issue! I had seen the illustration of breaking the stack pipe, but didn't want to if I didn't have to.

[LazyPup]

When looking at the repair flanges you will note that they make them in brass, steel and vinyl coated steel. While one might think the vinyl coated steel would resist corrosion better, in reality often the vinyl coating will crack and water is retained in those cracks which actually enhances rusting. In my experience, I have found the Brass repair flanges to have the best service life.

[diva]

Thank you so much for your help!

[hellomoto]

What if the mating pipe is galvanized pipe instead of cast iron? Can you twist the galvanized pipe off with a pair of pipe wrenches? Chiseling out the lead with the mating pipe still in the hub is going to be very tedious. any suggestions for situations where you can't just break the mating pipe off?

[LazyPup]

When installing a DWV (drain, waste & vent) system we must select the appropriate materials from a list provided in the codes and all House sewers, Main drains, branch drains, waste arms, stacks and vents must be sized in accordance with a set of very exacting tables provided in the codes.

When one considers that a single family residential dwelling will typically require a 3" main drain, and futher understanding that a 4" line has nearly 8 times the DFU (drainage fixture unit) load value of a 3" line, it would then stand that it would be nearly impossible for a residential structure to require a line greater than 4".

In residential applications Cast Iron pipe is generally used in sizes ranging from 2" to 4". Occassionally we will find 1-1/4" & 1-1/2" cast iron pipe but that is rare.

While cast iron pipe is seldomly used in residential applications today, before the introduction of ABS or PVC plastics, cast iron was the norm.

Typically all lines of 2", 2-1/2", 3" and 4" were cast iron, while the 1-1/2" or 1-1/4" lines were made of galvanized iron pipe, copper pipe, brass pipe or lead pipe.

A water closet is required to be connected to a 3" or 4" line, therefore you will never find a closet flange attached to a galvanized iron pipe.

Occassionally we will find a flat brass closet flange attached to the end of a 4" lead closet bend, which was a lead pipe 90deg elbow made specifically for attaching the water closet. The use of lead piping is no longer permitted and when we encounter lead closet bends that need repair we are required to replace them with Cast Iron, PVC or ABS.

When copper or brass pipe is joined to a cast iron pipe system it is usually joined by means of a leaded joint in the same manner as a cast iron to cast iron joint.

When galvanized iron pipe was used to make the 1-1/4" or 1-1/2" branches or waste arms it was normally attached to the cast iron pipe by means of a sanitary tee that had an NPT (National Pipe Taper) threaded hub as the side opening. Pipe dope was applied to the galvanized pipe threads and the pipe was screwed directly into the cast iron hub. Occassionally we do find instances where the galvanized iron pipe was set directly into the cast iron pipe hub and leaded in place.

Depending upon the age and amount of rust on the cast iron and galvanized pipe it is occassionally possible to unscrew a galvanized to cast iron threaded joint but it is highly unlikely that a typical homeowner would have the means to do it. In my experience to unscrew a 1-1/2" galvanized iron pipe from a cast iron hub you will need a 48" or 60" pipe wrench. (at over $200 a copy not many homeowners have a 5ft long pipe wrench lying around their shop area.)

The easy solution is to cut the galvanized pipe off about 3" from the hub then join your new ABS or PVC by means of a rubber FERNCO coupling however in instances where the point of the leak is at the threaded end of the galvanized your only option is to either remove the galvanized or replace the cast iron tee.

Removing the galvanized pipe from the threaded cast hub or a leaded hub is at best a very tedious labor intensive job. You begin by cutting the galvanized about 1/2" to 3/4" from the face of the hub. You then use a heavy hammer and a chisel or drift punch to drive one wall of the galvanized pipe inwards. As the pipe wall folds in on itself it ultimately reduces the outside diameter of the galvanized to a point where you can pry it out.

Once the galvanized pipe is out, if you have a threaded hub you can clean the threads with a wire brush, then apply pipe dope to a PVC or ABS thread adapter and screw that in place to start your new run.

If it is a leaded joint, once you have started to colapse the galvanized pipe in on itself you can try to pry the lead out in the manner described above.