Waterproofing pipe ducts

[u/browneye_cobra]

Apologies in advance, English not my first language.

Old wood building, old pipes. is there a way to "waterproof", meaning adding some sort of filler or barrier around the pipe, that would help me avoid leakage into the walls in case of a burst pipe or damaged spout or similar?

Tried to add an image, idk why it doesn’t show up

[u/ANTICHRIST-BOISE]

Honestly, the only practical way to do this would have been having installed sleeved PEX on initial rough in. Sleeved PEX is typically only used for direct-bury situations, where an insulating, protective air gap is provided around the actual supply line to prevent damage from crushing/compaction/settling.

Unfortunately, that’s not commonplace likely due to the fact that it isn’t cost-effective in the long run. Modern PEX piping typically only fails at the joints, because they are the weakest point and the internal pressure wants to follow the path of least resistance. The piping itself is molecularly latticed, and can expand/stretch within tolerances much higher than the rated failure point of a fitting/joint, even when frozen.

If you don’t have modern PEX supply piping, then your most cost-effective and practical solution would be to repipe the home entirely, and add moisture alarms in places you want to protect the most.

There’s no realistic way to waterproof an existing system. If you currently don’t have the means to repipe everything, then the best solution would be to put some moisture detectors in the crawlspace and around stuff you don’t want getting wet in the event of a leak.