Frozen Pipes: How to Thaw Them Without Causing a Burst

Homes built for a climate that rarely drops below freezing do not insulate the way homes in Ohio or Minnesota do. Across the Golden Triangle, and especially in the pre-1960 housing that came out of the Spindletop oil boom, water lines commonly run through exterior walls, unconditioned attics, and crawlspaces with little or no insulation, because for most of the year that is not a problem. Slab-on-grade construction adds another exposure point. Pipe running near the outer edge of a slab, close to where the foundation meets open air, sits closer to ambient cold than a line buried deeper inland would. None of this is a defect. It is a house built correctly for the climate it actually has, which happens to occasionally throw a week like February 2021 at it anyway.

A frozen pipe usually announces itself as a fixture that will not run, or runs at a trickle, while the rest of the house works fine. Turn on the faucet closest to where you suspect the freeze. If nothing comes out, or barely anything does, and you can trace the line to a section running along an exterior wall or through the attic, that is your suspect. The distinction that matters is whether the pipe has already split. If you hear running water somewhere in the house with every faucet closed, or see a wet spot on a wall, ceiling, or floor near that line, ice has already expanded past what the pipe could hold. At that point you are not thawing a frozen pipe anymore, you are managing a burst one, and the first move changes from applying heat to shutting off the main.

Open the faucet the frozen section feeds before you start warming anything. That gives melting ice somewhere to go and lets you hear the moment water starts moving again. Then apply heat gradually, starting near the faucet end and working back toward the blockage, using a hair dryer on a low setting, an electric heating pad wrapped around the pipe, or towels soaked in hot water and reapplied as they cool. One caution on the electric options: do not run a hair dryer, a heating pad, or any other plug-in tool while you are standing in water or working in a wet crawlspace. If the area around the frozen pipe is already wet, use the hot towels instead, or stop and call. What you never use is an open flame. A propane torch thaws a pipe fast, and it also turns the water inside it to steam faster than it can expand out through a faucet, which is exactly how a frozen copper pipe cracks under a torch when it would have survived slower heat. It is also a straightforward way to start a fire inside a wall cavity where you cannot see it happening. If the frozen section is behind drywall or under the slab and you cannot reach it directly, that is the point to stop and call rather than opening a wall on a guess.

Winter Storm Uri put Southeast Texas below freezing for days, not hours, and the region's exposed pipe runs were not built to sit at that temperature for that long. The failures that came out of it were not limited to one kind of house. Older homes in Beaumont and Port Arthur split at exterior wall runs, and newer construction out toward Nederland and Lumberton lost attic lines that had never seen a sustained freeze before. The fix that actually holds up is boring: foam pipe insulation on any exposed run, heat tape on lines that have frozen before, and letting a few faucets drip during a hard freeze warning so water keeps moving instead of sitting still in a cold pipe. None of that is expensive or complicated, and all of it is cheaper than the repair that follows a split. If a home has frozen in the same spot more than once, that is usually a sign the exposure needs to be fixed permanently rather than managed every winter.