Replumbing Entire House

More pics from my fixer upper. When I bought the house, I knew the plumbing was on its way out. A home inspection revealed the cast iron sewer stack was repaired with less than ideal materials. I contemplated not buying the house since the plumbing was grandfathered from 1890 and if I touched any portion of the sewer stack, the entire stack would have needed to be brought up to date. But I got a good price so I proceeded.

I reasoned that I would soon have both kitchen and both bathrooms gutted to the studs and all sewer infrastructure would be exposed from these rooms. So why not replace it at this opportune moment? Entire sewer stack will be replaced with PVC along with new runs to all plumbing points.

Dealing with a single 4 inch stack that drains the 2 bathrooms and a feeder 3 inch stack that drains the 2 kitchens. Link to album https://goo.gl/photos/EXxPjYKmmnGqjNQ29 or individual picture links wth descriptions below.

Main stack in basement: https://goo.gl/photos/XyD9uA4rVyH392iH7 Note the later addition of laundry drainage; the trap propped up by some bricks.

The main stack looks good, cast iron in good shape with joints holding up. https://goo.gl/photos/4Nnx7DhcVucGnc7g8 Shame I have to get rid of it but this will be sold for scrap. Some of the joints are solid as hell, the lead bead can be clearly seen and no leaks, rust etc...

Kitchen feeder stack. When exposed from behind wall, revealed rotting pipe https://goo.gl/photos/HTP1q6KyudT1uYha8 & https://goo.gl/photos/9hBWwzcSd1yh2tPr6

Cracked hub from improper toilet installation. Also wrong sealant used for PVC to cast iron. Note the cracked hub caused by forcing PVC into brittle cast iron that extends into main body of pipe.. Very slow leak. https://goo.gl/photos/oybYuaP1tp2qeEom7 & https://goo.gl/photos/B4gBzZ9jYwPC2GUy7

Bathroom sink PVC to cast iron joint failed, the PVC can be pulled straight out with hand force. Also wrong sealant used. https://goo.gl/photos/eQ9wf8o2N8rWn8YT6

Kitchen feeder pipe extensive rusted and in worst shape. Actively leaking at joint between feeder pipe and main stack (only sink water so not bad to clean up). Probably also due to botched install/repair as pipe is angled up, eliminating downhill slope causing water to pool at joint. Note use of non approved putty substance to repair rust https://goo.gl/photos/UqHZNx3nkRUZ4Lev5.

Rest of kitchen feeder. https://goo.gl/photos/RKpVkWPoGhmfWqWG7 Yep, thats epoxy resin used to patch what looks like a 5 foot long crack along the bottom of the pipe.

Other bad plumbing, note the green copper caused by leaking over the years. https://goo.gl/photos/LTaRQJQWhUzRwpDP6, https://goo.gl/photos/o3BjFZ11P7tq5jKB7 & https://goo.gl/photos/F9QdWjYa9kwhjkXK6

Questions.

1. Plumber wants to replace all faucet, tub, toilet runs with PEX. I don't mind copper as it has been tried and true. But no experience with PEX. He says he has never had a problem and I may allow him to do it for the ease of installation and cost savings of not using copper.

2. How come cast iron was used, in direct contact with water and air and has not rusted? Im clearly not understanding something about how cast iron rusts or withstands water/air. How do some pipes not rust and others do when all exposed to same water/air?

3. The main stack runs from basement, up through the 2 floors and into attic where it emerges from roof to serve as vent stack. We reasoned that if we cut the stack, we will leave the last few feet of original pipe sticking through the roof. The stack does not have one of those pipe boots that permits a clean penetration. Instead there is roofing tar inside and outside of the roof that seals the hole. Removing the pipe is going to mean roofing work.

To (hopefully) avoid this, we are going to build a platform/support out of 2x4s to support the pipe hanging down into attic so we can cut it and then connect that to the future PVC stack. This part makes me kinda nervous as if the seal is disturbed, thats a roof leak. The idea of climbing on a 3rd story roof to slap tar around a pipe is not appealing at all. I was thinking of putting more tar from the inside of the attic around the hole just in case. Opinions?

NJJoe wrote: Questions.

1. Plumber wants to replace all faucet, tub, toilet runs with PEX. I don't mind copper as it has been tried and true. But no experience with PEX. He says he has never had a problem and I may allow him to do it for the ease of installation and cost savings of not using copper.

2. How come cast iron was used, in direct contact with water and air and has not rusted? Im clearly not understanding something about how cast iron rusts or withstands water/air. How do some pipes not rust and others do when all exposed to same water/air?

3. The main stack runs from basement, up through the 2 floors and into attic where it emerges from roof to serve as vent stack. We reasoned that if we cut the stack, we will leave the last few feet of original pipe sticking through the roof. The stack does not have one of those pipe boots that permits a clean penetration. Instead there is roofing tar inside and outside of the roof that seals the hole. Removing the pipe is going to mean roofing work.

To (hopefully) avoid this, we are going to build a platform/support out of 2x4s to support the pipe hanging down into attic so we can cut it and then connect that to the future PVC stack. This part makes me kinda nervous as if the seal is disturbed, thats a roof leak. The idea of climbing on a 3rd story roof to slap tar around a pipe is not appealing at all. I was thinking of putting more tar from the inside of the attic around the hole just in case. Opinions?

Pex with last a long time. but tell the plumber that in areas it will be exposed it has to be a neat job, no loops or bows in the lines.
Cast Iron, if I remember correctly does not rust the way steel does because of it's high carbon content. It will rust over time or from chemical action. To make steel from cast iron you have to burn the carbon out of the iron and than add back in the amount you want in the alloy
On some jobs we had to install a section of No-Hub cast iron through the roof, no PVC was allowed to show above the roof. But connecting the new vent stack to the old one is not a good Idea. The way they sealed it to the roof is asking for trouble, hire a roofer and have him install a new boot on the pipe, after you remove the old stack but before you remove the piece penetrating the roof.
Cut the old stack off and place a sewer cap over the end of the pipe and than remove it just prior to the pipe being removed. If you want cast iron out through the roof for looks than buy a new piece for that. Or you can paint the PVC flat black .