Frozen pipe repair

What to do right now

If a pipe is frozen but not yet leaking. Open the tap that line feeds, both hot and cold. That gives melting water somewhere to go and relieves the pressure that does the damage. Leave it open while you work.

Find your main shut-off before you do anything else. Usually at the meter box near the street, or where the supply enters the garage. Confirm it turns. Doing this now, while nothing is wrong, is worth more than any other preparation.

If water is running or a pipe has split. Shut the main off immediately. Then open the lowest taps in the house to drain what is in the system and reduce what escapes.

Turn off the water heater if the house is being drained. Gas to pilot, electric at the breaker. An element firing in a tank that empties destroys it in seconds.

Electricity and water together. If water is anywhere near an electrical panel, an outlet or a light fitting, shut off that circuit at the breaker, and if you cannot do it safely, do not do it.

Move what you can out of the water's path and start taking photographs. Insurance claims go far more smoothly with pictures taken before the mopping starts.

Then call. Freeze events produce enormous call volume statewide, so call early rather than waiting to see how it develops.

Why Texas houses freeze so badly

The same freeze in a northern state does far less damage, and the reasons are all about how houses here are built.

Pipes run through unconditioned space. Attic distribution is standard on Texas slab houses. In Minnesota, supply pipe is kept inside the heated envelope; here, a great deal of it sits above the insulation where the temperature tracks outside.

Exterior wall runs. Common, and frequently with insulation behind the pipe rather than in front of it, which puts the pipe on the cold side of the barrier.

Uninsulated hose bibs and exposed exterior pipe. The single most common failure point, and the source of most of the damage after any Texas freeze.

Vented crawlspaces on pier and beam houses, with supply and drain lines fully exposed to outside air.

Garages and unheated utility rooms housing water heaters, softeners and their connections.

Slab houses have almost no protected space. There is no basement running at a stable temperature, which is where northern houses put everything vulnerable.

And the events are getting harder to dismiss. The multi-day statewide freezes of recent years produced hundreds of thousands of failures in houses built on the assumption that a hard freeze lasts one night.

Thawing safely

Never use an open flame. Not a torch, not a propane heater aimed at pipe, not anything with a naked flame. It is how frozen pipe calls become house fire calls, and it happens every single freeze event.

Open the tap first. Always. Melting water needs an escape route, and a closed system with expanding ice is what splits pipe.

Apply gentle heat, starting at the tap end. Work backwards towards the frozen section. Starting in the middle can trap melt water between two plugs of ice, which raises pressure exactly where you are trying to relieve it.

What works. A hair dryer moved constantly along the pipe. A heat gun on a low setting, kept moving. Warm towels wrapped round the pipe and re-soaked. A space heater warming the room the pipe runs through, slower and safer, and often the right answer for a wall cavity you cannot reach.

Give it time. A hair dryer on an accessible pipe may take twenty minutes. Warming a whole attic or crawlspace back above freezing takes hours.

Pipe inside a wall is not reachable directly. Warm the room, open cabinet doors under sinks on exterior walls, and be patient. Cutting into a wall to reach a pipe that is still frozen achieves nothing that warmth would not.

Watch as it thaws. Stay by the tap. The moment flow returns, check every part of that run you can see and listen at the walls. A split announces itself the second the ice clears.

If it will not thaw, or if you find no flow anywhere, stop and call. A section that will not clear may already be split.

What splits, and what it takes to fix

Copper splits along its length, typically a clean longitudinal tear an inch or two long. Repaired by cutting out the section and fitting new pipe. Where copper has split in one place during a freeze, the whole exposed run gets inspected. Freeze damage is rarely solitary.

PEX often survives. It expands with the ice and returns. This is genuinely one of its advantages and it is why so many repiped houses came through recent freezes intact. Fittings are still vulnerable, and PEX that has been stretched severely gets replaced rather than trusted.

CPVC is the worst performer. It becomes brittle in cold and shatters rather than splitting, sometimes at several points along a run.

Galvanised steel splits at threaded joints where the wall is thinnest.

Hose bibs and their wall connections are the most common casualty of all, and the split is usually in the pipe inside the wall rather than in the visible tap.

Water heaters in unheated garages and attics, where connections and the drain valve freeze.

Fire sprinkler lines in houses that have them. These fail spectacularly and are a specialist repair.

The repair itself is straightforward where the pipe is accessible: isolate, cut out the damaged section, join in new pipe, pressure test. It becomes a bigger job when the split is inside a wall or under a slab, and where several splits appear along one run, replacing the whole run is faster and cheaper than chasing them individually.

After the thaw: checking the whole house

A house can come through a freeze with no visible problem and still have a split waiting. Work through this once things are properly above freezing.

Every outdoor tap. One person outside opening it, one inside listening at the wall. Weak flow, no flow, or a rushing sound inside the wall means shut off and call.

Every fixture in the house, hot and cold. Anything that produces nothing is a line that has not thawed or has failed.

The attic, with a torch, looking for wet insulation, drips, or a stain on the underside of the roof deck or the ceiling.

Ceilings, especially under bathrooms and near exterior walls. A fresh stain is a leak in progress.

The water heater and its connections, the softener, and any filtration equipment in a garage.

The irrigation backflow preventer outside, among the most freeze-vulnerable items on the property and easy to forget.

The meter test. Turn off every fixture in the house and watch the meter's leak indicator. If it is moving with nothing running, water is escaping somewhere.

Listen at night. With the house quiet, a running leak inside a wall is often audible when it is inaudible during the day.