I have an underground p trap for my tub, how to prevent it from freezing?

Discussion in 'Plumbing Forum' started by amodoko, Dec 24, 2011.

  1. Dec 24, 2011 #1

    amodoko

    amodoko

    amodoko

    Well-Known Member

    Joined:
    Jun 26, 2010
    Messages:
    60
    Likes Received:
    1
    Hi guys, I have a condo that is built on a slab and am currently installing the plumbing to a new tub. There is no access to my p trap once a tub is in place due to the house being on a slab. Below the slab is about 13 feet of open space, so the p-trap will just be exposed to the air that is enclosed under my home. This air is not temperature controlled and is basically the temperature it is outside except that it is surrounded by cement walls. I am worried about the water freezing in the p trap during the cold winter months (temperatures can reach 0 degrees F here in the midwest at times), or the frigid temperatures cracking my pvc cement bonds. I don't know if this is possible, but I was concerned about it.

    My questions are: Will the water freeze in my schedule 40 pvc p trap if the tub is not used more than once a month, even though my heat is on inside the condo? Do I need to put pipe insulation around the p trap or is this unnecessary? Do I need to actually go down there and insulate the cement walls to keep the temperature warmer in there? Or do I need to buy some heating device, like heat tape?

    Thanks, just trying to figure out how my plumbing will be okay if there is no insulation down there since it can be so cold. I appreciate the help:)
     
  2. Dec 24, 2011 #2

    oldognewtrick

    oldognewtrick

    oldognewtrick

    Administrator Staff Member Admin Moderator

    Joined:
    Jul 26, 2009
    Messages:
    10,811
    Likes Received:
    1,433
    When you refer to your condo being on a slab what material are you talking about? Is this a new location for plumbing, was there a tub there before? If so how was it weather proofed before? You say you have 13' of space below, is this soil or is this where the slab is?
     
  3. Dec 24, 2011 #3

    amodoko

    amodoko

    amodoko

    Well-Known Member

    Joined:
    Jun 26, 2010
    Messages:
    60
    Likes Received:
    1
    Hey, thanks for the reply. When I say slab, I mean the house was built on a layed cement floor. It is not on a wooden frame, it is on a cement and metal frame. So when you pull up the floor, there is just a slab of cement. There wasn't any insulation there before, but there also was someone using that tub regularly. In the future, it will be used much less because my roommate may move out and that is when I will be concerned. I have posted pics of what it looks like under the p trap so you can see what i mean. Thanks again for your reply, and let me know if you think I should do anything to protect the trap:)

    IMG_1083.jpg

    IMG_1086.jpg

    IMG_1089.jpg

    IMG_1090.jpg

    IMG_1096.jpg
     
  4. Dec 24, 2011 #4

    Redwood

    Redwood

    Redwood

    Certified Lunatic

    Joined:
    Apr 14, 2009
    Messages:
    887
    Likes Received:
    0
    Has it frozen before?

    Are other similar units having a freezing problem?
     
  5. Dec 25, 2011 #5

    amodoko

    amodoko

    amodoko

    Well-Known Member

    Joined:
    Jun 26, 2010
    Messages:
    60
    Likes Received:
    1
    Not that I know of, I was more worried about it freezing when it wasn't in use when my roommate moves out. But I am sure I am being overly cautious/anal and it should be fine. I may just put some pipe insulation on the trap
     
  6. Dec 26, 2011 #6

    isola96

    isola96

    isola96

    Senior Member

    Joined:
    Oct 15, 2011
    Messages:
    437
    Likes Received:
    7
    Low voltage heating wires the stuff used on roofs to melt the snow and ice maybe something to consider.
     
  7. Dec 26, 2011 #7

    Redwood

    Redwood

    Redwood

    Certified Lunatic

    Joined:
    Apr 14, 2009
    Messages:
    887
    Likes Received:
    0
    There are heat tapes specifically made for plumbing that can be used but there are specific requirements about clearance to combustibles and going through walls and floors which must be followed.

    Frostex is the best there is IMHO...
     
  8. Dec 26, 2011 #8

    amodoko

    amodoko

    amodoko

    Well-Known Member

    Joined:
    Jun 26, 2010
    Messages:
    60
    Likes Received:
    1
    Okay cool, thanks everyone. I will look into the options and decide what I should do.
     

Share This Page