Frozen and Burst Pipe Repairs

The ice does not split the pipe. Water expands as it freezes and forms a plug, and that plug grows along the pipe toward the closed fixture at the end of the run. The water trapped between the advancing ice and that closed tap has nowhere to go, so pressure in the trapped section climbs until the weakest point gives out. That failure point is often well away from the frozen section, sometimes in a heated part of the building entirely.

It is also why so many bursts get discovered on the thaw rather than during the cold snap. The pipe splits while it is frozen and the ice keeps the opening sealed. Water starts moving once the temperature comes back up, frequently with nobody home, and the first sign is a ceiling coming down.

Copper splits along its length, often further than people expect. PEX has some give and survives a freeze better than copper does, but the brass fittings do not, and neither do valves, hose bibs or water meters.

Nearly always in the same handful of places. Supply lines running through an exterior wall cavity with the insulation on the wrong side of the pipe. Pipes crossing an unheated garage ceiling to feed a bathroom above. Crawl spaces and cold cellars with a vent left open in November. Additions and sunrooms built over open joists. Older houses in the old city are the worst for it, because runs went wherever they fit rather than wherever they belonged.

Hose bibs are the most common burst in the GTA and the most preventable one. A garden hose left connected in the fall holds water at the bib, and even a frost-free sillcock cannot drain with a hose still on it. The pipe splits inside the wall in January. Nobody knows until the tap is opened in April and water pours into the basement.

The other reliable pattern is an empty building with the heat turned down: a vacant listing, a unit between tenants, a house closed up for February. There is a difference between saving on heat and paying for a repipe and a restoration crew.

Never use an open flame. A torch on a frozen line is how houses catch fire, and it also flashes trapped water to steam, which can burst the pipe on the spot. Heat the space instead of the pipe. A space heater in the room, cabinet doors left open, a hair dryer moved slowly along the run. Open the tap that pipe feeds first, so meltwater has somewhere to go and so you can see the moment flow returns.

Once it runs, check the whole line before walking away. A pipe that froze may already be split and only looks intact while the ice is holding it shut.

The repair itself is usually straightforward. The useful part of the visit is working out why it froze, and that is generally fixable: insulating the run with the insulation between the pipe and the cold rather than behind it, air sealing wherever the cold air is actually getting in, rerouting a vulnerable section into conditioned space, changing a hose bib for a frost-free model with an interior shut-off and bleeder, or running self-regulating heat trace where rerouting is not practical. Wrapping insulation around a pipe with cold air blowing across it only slows the freeze down.