Ask Experts Questions for FREE Help !
Ask
    Hemlock50's Avatar
    Hemlock50 Posts: 36, Reputation: 2
    Junior Member
    		  
    #1

    Oct 30, 2009, 06:47 AM
    4'' cast iron vent stack through the roof
    Hi,
    Newbie here & need some advice on a recent bathroom re-model. When the walls were opened up, the 4" cast iron vent stack was badly corroded & replaced with about 10' of pvc going into the attic. Instead of going all the way through the roof with pvc, the guy doing the job connected the pvc to the old cast iron piece that goes through the roof. (about a 5' section which was in fine shape) I'm concerned about the weight of this top cast iron section being supported in part by the pvc below it. I do want to replace the cast iron iron & was wondering if this is something that needs immediate attention, or should it be OK to leave as is till Spring when the weather is better. Just wondering if there are any potential problems that could/might crop up if it isn't changed now. Thanks in advance.
    ballengerb1's Avatar
    ballengerb1 Posts: 27,378, Reputation: 2280
    Home Repair & Remodeling Expert
    		  
    #2

    Oct 30, 2009, 08:41 AM

    How much cast pipe sits on top of your bnew piece of PVC? If its only 3-5' I would not worry about it. Did he add any strapping to the PVC as it passes through the ceiling rafters?
    Hemlock50's Avatar
    Hemlock50 Posts: 36, Reputation: 2
    Junior Member
    		  
    #3

    Oct 30, 2009, 10:05 AM
    Quote Originally Posted by ballengerb1 View Post
    How much cast pipe sits on top of your bnew piece of PVC? If its only 3-5' I would not worry about it. Did he add any strapping to the PVC as it passes through the ceiling rafters?
    The cast iron section through the roof is close to 4' long. I forgot to mention the pvc is 3'', versus the 4" cast iron. He connected both pieces with a rubber collar/boot that has 2 stainless straps at each end. There's no kind of support strapping, if that's what you're referring to.
    Milo Dolezal's Avatar
    Milo Dolezal Posts: 7,192, Reputation: 523
    Plumbing Expert
    		  
    #4

    Oct 30, 2009, 12:31 PM

    You should not reduce from 4" to 3" and then go back to 4".

    As said above, structurally, I would not worry about it. Even though I would use Shielded couplings in place of Flex Seal coupling he used.
    Hemlock50's Avatar
    Hemlock50 Posts: 36, Reputation: 2
    Junior Member
    		  
    #5

    Oct 30, 2009, 03:44 PM

    OK, thanks very much guys. I do appreciate the input. As long as it should be OK for now, I'll leave it alone and replace the cast iron in the Spring. (or sooner if weather permits)
    Thanks again... great forum here!
    speedball1's Avatar
    speedball1 Posts: 29,301, Reputation: 1939
    Eternal Plumber
    		  
    #6

    Oct 30, 2009, 04:49 PM
    Next time use shielded metal couplings. They are more ridged then the neoprene couplings. Good luck, Tom
    Hemlock50's Avatar
    Hemlock50 Posts: 36, Reputation: 2
    Junior Member
    		  
    #7

    Oct 30, 2009, 06:01 PM

    Will do Tom. Thank you.
Not your question? Ask your question View similar questions
 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Cast iron to pvc transition for main vent stack [ 4 Answers ]

Hello to all. I am adding a 2nd story to my home. I have a 4" cast iron vent that y's off to pick up a galvanized 2" pipe for the bathroom below. I have a 2 part question. (A) The vent runs horizontally at a 90 for about 6 feet, then goes up through the roof. I would like to cut this out,...

Cast iron vent stack and PVC waste lines [ 1 Answers ]

I decided to replace the cast iron portions of my waste lines from a double vanity sink to the waste line. Previously a plumber had replaced the accessible portions with PVC so I have quite a mix. Now that I have opened up the wall, I see that I have a cast iron vent stack / hub (see pics: ) that...

Tap into Cast Iron Vertical Stack [ 11 Answers ]

I am considering taping into one of my cast iron stacks to add a drain. The cast iron is in very nice condition and has no problem. It runs into concrete on the bottom, the other side of the pipe has extensive plumbing connections attached to it, then it vents. Would the best thing to do be to...

Cast Iron Vent Stack [ 2 Answers ]

I have just purchased a 1950's rental property with a cast iron vent stack. The insurance co. wants me to replace it as they are prone to leaking in older homes. The job seems fairly straight forward, but do you have to replace the elbow/cleanout at the bottom that is cemented into the basement...

Cast iron vent stack [ 7 Answers ]

I'm installiing a new basement bathroom and when running a vent stack I would like to tap into the existing cast iron with PVC using a saddle on the cast. My question is what method is used to cut a hole in the cast iron, where I wish to place the saddle and connect the PVC.

View more questions Search