Live in CO in a 20 year old house that frequently had its heat set in the 50’s while not occupied in the winter. It’s new to us and we left for Christmas with heat set at 60. 3 days later a pipe in the crawl space between the roof deck and insulation above the ceiling burst. This crawl/ventilation space exchanges air with outside via some venting from what I can tell. Look at the picture and you will see the “error” in not insulating the pipe correctly. The pipe rests on the joists with insulation below it to the ceiling. But they are just exposed above the insulation here. We've had some work on some plumbing in another area of the house not related to this but water off and on. So 1. Why would anyone not insulate this pipe better(maybe it had some minimal insulation placed over it?)?? and 2. More importantly any guesses after many winters it finally gave way from a cold winters night? enter image description here

  • How much damage was done from water spraying out? How long was it spraying before the water was turned off? Dec 28, 2023 at 11:27
  • Surprised it has not happen before this. Copper/metal pipes not protected with water in them will usually burst during the first good freeze. If going away water pipes need the water turned off and the pipes drained unless all pipes are in the warm section. Attics and outside walls are the cold sections.
    – crip659
    Dec 28, 2023 at 12:15
  • 1
    Where those pipes are you want about a foot or more loose insulation above and on the sides and remove the insulation below to let a bit of heat up, to have any chance of not having a repeat.
    – crip659
    Dec 28, 2023 at 12:52
  • I'm surprised this hasn't happened before either. Didn't think I needed to turn off water being gone a week. But going forward I will be doing this. That sheathing is OBS to the outside and nearby is that vent for a bathroom fan. I am wondering if the cold air came in that vicinity and froze the pipe. Wondering if the insulation was lightly over the pipe originally and with the leak (which was spraying for about 12 hours, enough to flood the entire house and ruin the hardwood floors) the insulation settled below it some... Dec 28, 2023 at 17:54
  • Wildly unlikely: The previous owners had a circulation pump to keep the water moving. The rest of the plumbing would then serve as reverse radiators to pull heat out of the house. Note that this would make a power failure even more fun.
    – HABO
    Dec 28, 2023 at 18:30

2 Answers 2

  • 1: They were an idiot, or rodents stole the insulation for nest material. Idiot looks more likely, as I don't see any obvious rodent sign here.
  • 2: Kept warmer in winter and sufficient heat leakage to not freeze in the past, or it's been repaired without solving the idiot's insulation mistake some unknown number of times before you bought it. Or, they drained the pipes before leaving it in the winter if you understand it to have been left with heat set in the 50's in the past.

Almost certainly the pipes were drained in previous years. I can't imagine an attic not getting below freezing.

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