Am I Right To Be Feeling This Way?
Family Life1 min ago
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For more on marking an answer as the "Best Answer", please visit our FAQ.This sounds as if it hasn't been installed properly. Ideally the pipe should rise high inside in the warm and then fall to drain completely with no water traps to freeze. Why can't it go through the garage where it would be warmer instead of over the roof, this is very poor practice?
Copper pipe can split if it freezes so I would repipe it all and route inside wherever possible with larger size 28 mm plastic pipe to avoid ice build up and to withstand any further possible freezing. If traps are avoided you shouldn't need any lagging at all which can also delay any thawing. Larger normal waste pipe and fittings can also be used to drain the downhill section with even less chance of ice build up inside the pipe.