(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 4 of 4

Thread: Size of hole for (hot water) waste pipe

Hybrid View

  1. #1
    DIY Senior Member Taylor's Avatar
    Join Date
    Mar 2005
    Location
    Northern Joisey
    Posts
    143

    Default Size of hole for (hot water) waste pipe

    Quick question: how much leeway does a hole for DWV have to allow for expansion of the pipe?

    Installed i-joists under tub expressly for flexibiliity with holes. However the guy who speced them out for me gave me 9-1/2" instead of 11-/7/8", that's a difference of 2" hole vs 4" hole allowed where waste pipe would go. He must have been figuring it was enough for 1-1/2" tub drain, but in fact a 1-1/2" sch 40 DWV pipe leaves about 1/16" to 1/8" leeway around a 2" hole. Do I have anything to worry about when hot tub/shower water goes through that pipe?

    I know not to mess with specs on these i-joists, unlike dimensional lumber they just collapse when overloaded.

  2. #2
    Plumbing Contractor srdenny's Avatar
    Join Date
    Sep 2004
    Location
    SF Peninsula
    Posts
    361

    Default

    Run the trap arm in DWV copper. At 1-5/8" od it will have plenty of space to move unimpeeded.

  3. #3
    DIY Senior Member Taylor's Avatar
    Join Date
    Mar 2005
    Location
    Northern Joisey
    Posts
    143

    Default

    Copper is not really an option. PVC waste pipe already lead-soldered to waste stack (by plumber) and there isn't room enough for a PVC/copper coupling. I haven't drilled the hole for the waste pipe through the joist yet, I'm pretty sure that by doing it very carefully I can get a 2" hole spot on. I had to replace a joist that among other things had a 3" hole, too big....

    I think there was a thread here recently about copper waste pipes crumbling due to use of cleaners....

  4. #4
    DIY Senior Member Taylor's Avatar
    Join Date
    Mar 2005
    Location
    Northern Joisey
    Posts
    143

    Default

    Well called TrusJoist and I'm still okay for expected load with 2'6" hole, because of short span, so I can enlarge that hole a bit.

    Edit: Make that 2-1/2" hole....
    Last edited by Taylor; 06-21-2005 at 02:56 PM.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •