3" Iron pipe in wall when rest of house is PVC

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by JoshB-NC, Jun 9, 2021.

  1. JoshB-NC

    JoshB-NC Member

    Joined:
    Sep 20, 2012
    Location:
    North Carolina
    Doing a kitchen remodel and found a vertical 3" iron pipe that I need to move.

    Wondering why it is iron? House was built in 1989 and all other drains are PVC.

    Anyone have any insight? It is from a full upstairs bath.

    Thanks!
     
  2. wwhitney

    wwhitney Well-Known Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    Cast iron is heavier and reduces transmitted sound to the living space. So one strategy is to use it just for DWV risers that pass through a floor to serve an upper floor.

    Cheers, Wayne
     
    JoshB-NC likes this.
  3. Sponsor

    Sponsor Paid Advertisement

     
    JoshB-NC likes this.
  4. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    Ditto what Wayne mentions. We often will only do the vertical riser through a living space as the water travelling horizontally makes very little noise. Waste falling down the vertical separates and falls in a crazy pattern.. makes lots of noise.

    Cast iron can be replaced with a suitable sound deadening material like a dense self adhesive mastic/roofing material.
     
    JoshB-NC likes this.
  5. Jeff H Young

    Jeff H Young In the Trades

    Joined:
    Feb 27, 2020
    Location:
    92346
    or do like 90 plus percent of homes and go all plastic. No doubt I love cast iron but its more time and money. just depends on budget and desire to have "the quiet pipe" (one of the manufactures I think trademarked the name)
     
  6. JoshB-NC

    JoshB-NC Member

    Joined:
    Sep 20, 2012
    Location:
    North Carolina
    Ok that makes sense. In the same area we have a 1.5" pvc vertical bath drain in a wall and it is pretty noisy.

    Any preferred soundproofing for pvc? Googled it and it seems automotive dynamat sounds popular? Rather not have the sound if possible.. kids use that bathroom a lot....
     
  7. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    Anything that increases the density and reduces the vibration of the pipe. Dynamat is pretty expensive. I've used a self adhesive asphalt roofing material. Lots of car guys I know use roofing material too in their cars to cut out noise transmission. And theres always an argument as to whether you Need to cover the material 100% or just enough to cut the vibration. Full coverage will do that, but it may cost a lot. I've also heard of people using a sound deadening spray foam.. but I've never seen that product either. Likely it accomplishes the same vibration dampening.
     
    JoshB-NC likes this.
  8. JoshB-NC

    JoshB-NC Member

    Joined:
    Sep 20, 2012
    Location:
    North Carolina
    If you do wrap the pvc pipe will it be as quiet as the iron pipe? Or would I be better off moving the iron pipe and reusing?

    I know there are knock-offs of dynamat. And I know exactly that roofing material your talking about.. man that stuff really sticks.
     
  9. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    When we did a 100 unit hotel and wrapped the pipe with 2 layers of 1/4" thick self adhesive asphalt.. it was the same rating on the decible meter as cast iron.

    We performed tests on several lenghts of pipe with varied sound deadening materials prior to installation.

    Adding rock wool around the pipe after will cut the noise probably to nothing. But you also need to consider there will be some transfer if the pipe comes into contact with the building too.. thres always some noise.
     
    JoshB-NC likes this.
  10. Jeff H Young

    Jeff H Young In the Trades

    Joined:
    Feb 27, 2020
    Location:
    92346
    I've only heard of people attempting to fix objectional noise. but never knew that plastic pipe wrapped could be quieter than cast iron. I haven't ever had a complaint with all cast iron waste job
     
    JoshB-NC likes this.
  11. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    Cast iron is super expensive to install. Someone can pay for a PVC installation and sound deaden plastic themselves after the fact saving a lot of money. I still have the decibel meter we used for that project to test each system. The difference is measurable with a device, but not detectable to the ear.
     
    Jeff H Young likes this.
  12. wwhitney

    wwhitney Well-Known Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    But that's basically the only downside, right? Anything you can do to soundproof PVC, you could do to the cast iron and get an even better result. Although to less net effect, since the starting point is better.

    Cheers, Wayne
     
  13. Jeff H Young

    Jeff H Young In the Trades

    Joined:
    Feb 27, 2020
    Location:
    92346
    Thanks Tuttles, I've only tried to quiet noisy wastes a few times with little success . but attempts weren't that hard and I've cut plastic out and replaced with cast when they were serious about it.
    Cast does raise cost depending on the property and project the price can be super expensive. a 200k home vs a 2 million dollar a thousand dollars could be a ton of money . I work mostly in a cheaper area of so cal where we are used to the sound and not as objectionable. but condos can be a real problem with noise and lawsuits over them being noisy especially from neighbors
     
  14. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    Cast Iron for noise control:

    Yes, some homes will use cast for the drains, sometimes plastic on the venting to save some money. I've plumbed some condos in nothing but cast iron no-hub.
    I plumbed one home in Clyde Hill where the Median sales price this year is $3,490,000. This was back in the late 80's though. I had just done my home building thing, and had gone back to plumbing. I had quoted to plumb this guys home, a big investor from Las Vegas I had heard, but kind of wondering that if he was such a big deal why he didn't have a plumber or other contractors that were his "go to" guys. Everyone else had worked with had long term relationships with their subs.
    So I plumbed his home according to the contract, and when I was done, he wanted his

    "I have more money than you, I want my rich persons discount".

    Yes, he was complaining that I used noisy copper piping for water and ABS for waste and vents. He thought his beauty of a home was needing more than what the contract called for. I laughed and said his was a pretty average home and I had built homes that were nicer. That made him mad and he called me a liar. Funny considering that he was the one being cheap. And I had the proof to back up my statements.

    He cut me a check for a partial amount. I took him to small claims court. Our court date was going to be December 28th, right in the middle of the Christmas break. He was furious. I went to his office in downtown Bellevue, an entire floor of a high rise there. At one point as I was sitting, he stood up, leaned over me and he cocked his arm as if he was going to slug me in the head. The guy with him had this horrified look on his face watching this go down. I was thinking, you know me, the son of a judge in Bellevue, and one of five boys that fought for fun, I had helped get my 6'3" brother ready for his heavyweight fights by sparring with him, and that if he proceeded to slug me, well, I was going to own him. And it wasn't like I hadn't been slugged plenty of times in the head and by my brothers who were bigger and stronger. The moment passed and I left the building.
    Later, a woman from the office called and said she would have the check for me.
    I met her, and she came with her husband to hand the check over.
    The entire thing seemed like something out of a strange movie, the drama and the fear in that office. I suppose that she had thought that anybody that would stand up to her boss must have been really scary. Unbelievable. From my standpoint, it was more like being on a job site and fighting over the music being played, or where we were plugging in our power cords. This white collar guy was trying to do the intimidation thing with a plumber. Not happening. And of course it helped growing up hanging out with my friend whose dad was chief of police, and my father who was the local judge. You just have to marvel at the people that think they are the mafia.

    [​IMG]

    1987 Sun Design Homes

    [​IMG]

    Little 6'3" brother Shannon with the white glasses. He loved boxing and Kung Fu.
     
    Last edited: Jun 15, 2021 at 6:01 PM
    JoshB-NC likes this.
  15. Jeff H Young

    Jeff H Young In the Trades

    Joined:
    Feb 27, 2020
    Location:
    92346
    I had one home I plumbed built for speculation. the guy sold it to a lawyer who in turn sued basicaly every sub contractor plus the builder. they said we all conspired to cheat the buyer, substandard work yada yada yada... our issue was noisy waste lines and supposed failure to provide warranty work just utter BS. Had to turn it over to insurance company never was certain if they settled or not.
     
  16. JoshB-NC

    JoshB-NC Member

    Joined:
    Sep 20, 2012
    Location:
    North Carolina
    GREAT STORY


     
Similar Threads: Iron pipe
Forum Title Date
Plumbing Forum, Professional & DIY Advice Question regarding pipe supports Iron vs Brass May 19, 2021
Plumbing Forum, Professional & DIY Advice Can you fully bury 2" black iron pipe threads into fitting? May 9, 2021
Plumbing Forum, Professional & DIY Advice Clumps on Cast Iron Pipe Apr 24, 2021
Plumbing Forum, Professional & DIY Advice Converting a cast iron hot water radiator to steam (single pipe) Apr 2, 2021
Plumbing Forum, Professional & DIY Advice Connecting PVC to Cast Iron Elbow that is Tilted / Should I replace Cast Iron Pipes? Mar 18, 2021

Share This Page