How to prevent this water line from freezing again?

Old 02-07-22, 11:04 AM
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How to prevent this water line from freezing again?

So I had an electrical line (not pictured, but to the right of this location) stubbed out to tap into in the future, going through this same wall to the exterior. The electrician who did it, forgot to insulate and seal off the hole that the conduit runs through. You know where this is going. After a recent cold snap, the circled water line above, which runs along the inside of that exterior wall, froze and burst, almost definitely due to the cold air getting in through that conduit hole.

Before I close this wall back up, I'm trying to figure out what the best way to insulate against this happening again is. Even if I properly insulate around the conduit hole, since I will be insulating and drywalling, no ambient air from the conditioned interior can get to the pipe, do I run the risk of this pipe still getting dangerously cold? What else can I do to prevent it from ever freezing again?
Old 02-07-22, 11:09 AM
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If it's on the cold side and fully sealed off, no heat, then there is a chance it can freeze.

Insulate on the exterior side and remove insulation on the interior side so that heat can get to the pipe.
Old 02-07-22, 01:24 PM
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It's hard to get a bearing in that picture. A picture from further away would be helpful.
Old 02-07-22, 02:27 PM
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Here is a picture from a bit farther out. This is located in my finished basement.

Old 02-07-22, 02:33 PM
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Water lines should not be out against the exterior side of exterior walls or exterior attic walls or crawlspaces, they need to be on the INTERIOR side of the insulation. You also don't put heat tape inside walls unless you want to create a fire hazard. The best thing you can do is air seal the exterior side of the water pipes with rigid foam and spray foam the edges to stop any wind from blowing in. When wind can blow in, that's when pipes freeze. If you put any fiberglass in, be sure it is behind the pipes (exterior side only), not in front of them, because you don't want to block interior heat from getting to the pipes.

If you can get into that space behind the wall, sheet the whole thing with rigid foam.

Last edited by XSleeper; 02-07-22 at 02:50 PM. Reason: Spelling

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