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Triad winters do not stay cold for long, and that is exactly why burst pipes catch people out here. A single night in the teens is enough to freeze an uninsulated line in a crawl space or an exterior wall, and the break often shows up hours later when the ice thaws. Knowing how to protect pipes during cold weather is mostly about doing a short list of things in the fall and a shorter list when a hard freeze is forecast.
Key Takeaways
- Water expands as it freezes, and the burst usually happens between the ice plug and the closed faucet.
- Crawl spaces, garages, attics and exterior walls are where Triad pipes freeze.
- Disconnect garden hoses in the fall. A connected hose is the most common cause of a split hose bib.
- Let a cold tap drip during a hard freeze and open cabinet doors under sinks on exterior walls.
- Know your main shutoff location before the freeze, not during it.
Do These Before the First Freeze
Start outside. Disconnect every garden hose, drain it and store it. Water left in a hose has nowhere to go, and it freezes back into the spigot and splits the pipe behind the wall. If you have interior shutoff valves for outdoor spigots, close them and open the spigot to drain the line.
Then walk the crawl space with a flashlight. Look for pipes with no insulation, gaps in the foundation vents and any spot where outside air blows directly onto a water line. Foam pipe sleeves are inexpensive and go on in minutes. If a spigot already leaks or drips, get the outdoor spigot replaced before the cold arrives rather than after it splits.
Insulate the Pipes That Actually Freeze
Not every pipe needs insulation. The ones that freeze are in unheated or poorly sealed space: crawl spaces, attics, garages, exterior walls and unheated utility rooms. Foam sleeves handle most of these. For a run that has frozen before, self regulating heat cable rated for water pipe is a better answer, because insulation alone only slows heat loss, it does not add heat.
The national plumbing code bodies treat pipe protection in unconditioned space as a design requirement rather than an optional extra. Seal the air leaks while you are in there. A pipe in a sealed crawl space with a small amount of ambient heat will survive a night that splits the same pipe sitting in a draft. Closing foundation vents in winter helps, as long as you open them again in the spring.
What to Do When a Hard Freeze Is Forecast
Let a cold water tap drip from the fixture furthest from where the line enters the house. Moving water is much harder to freeze, and an open faucet gives expanding ice somewhere to push. A steady drip is enough, you do not need a running stream.
Open cabinet doors under sinks on exterior walls so room air reaches the pipes. Keep the thermostat at the same temperature day and night rather than setting it back, and if you are leaving town, do not drop the heat below about 55 degrees. The National Weather Service cold safety page is a good place to check how long the freeze will last.
If a Pipe Is Already Frozen
You will usually notice because one fixture has stopped while others still run. Leave that faucet open, because it gives melting water an escape route and relieves pressure. Then warm the pipe from the faucet end back toward the frozen section using a hair dryer, a heat lamp at a safe distance, or towels soaked in hot water.
Never use a torch, a propane heater or any open flame on a pipe. It is a fire risk, it can damage the pipe, and on a plastic line it will melt it. If you cannot reach the frozen section or the pipe is inside a wall, that is the point to call rather than start cutting drywall.
If a Pipe Has Burst
Close the main shutoff immediately. Every minute the line stays pressurized adds water to the structure. Cut power at the breaker to any area where water is near outlets or fixtures. Then call for emergency plumbing service and start photographing everything for your insurer.
Burst pipes often show up during the thaw rather than during the freeze, because the ice plug is holding the water back while it is solid. If you had a freeze and a pipe that has been quiet, keep an eye on it as temperatures come back up. Our post on when a plumbing problem is an emergency covers what to shut off first.
Pipe Material Matters More Than People Think
Copper splits cleanly when it freezes and usually fails at a straight run or a joint. CPVC becomes brittle in cold and can shatter. PEX has more give than either and often survives a freeze that would break copper, though it is not freeze proof and the fittings can still fail.
If you are already planning a repipe or a remodel, freeze resistance is one more point in favor of PEX for runs through unheated space. Our comparison of PEX and copper pipe goes through the trade offs, and choosing pipe material by job covers the rest.
Getting a Vacant or Seasonal Home Through Winter
An empty house is the worst case, because nobody is there to notice the drip stopped. If the property will sit empty for weeks, the safest approach is to shut off the water at the main, open all the fixtures and drain the system. Leave the heat on at a low setting anyway to protect the structure.
For a house that is only empty for a long weekend, leaving the heat at 55 degrees, opening cabinet doors and letting one tap drip is usually enough. Ask a neighbor to look in if a hard freeze is forecast while you are gone.
| Where the pipe runs | Freeze risk | Protection that works |
|---|---|---|
| Crawl space | High | Foam sleeves, seal air leaks, close vents |
| Exterior wall | High | Open cabinet doors, let the tap drip |
| Unheated garage | High | Insulate, keep the door closed |
| Attic | Medium to high | Insulate, add heat cable if it has frozen before |
| Outdoor spigot | High | Disconnect hoses, drain, use a frost proof bib |
| Interior heated wall | Low | No action needed |
Protecting Pipes in Cold Weather: Frequently Asked Questions
How do I protect pipes during cold weather?
Disconnect and drain garden hoses in the fall, insulate pipes in crawl spaces, garages and attics, seal air leaks near water lines, and during a hard freeze let one cold tap drip while opening cabinet doors on exterior walls. Keep the thermostat steady overnight.
At what temperature do pipes freeze?
Pipes in unheated space start to be at risk around 20 degrees Fahrenheit, though a well insulated pipe in a sealed crawl space can survive lower. Wind and a draft matter as much as the number, because moving cold air strips heat from the pipe much faster.
Should I let my faucet drip all winter?
No, only during a hard freeze. A drip is a safeguard for the nights when temperatures fall into the teens or below, not a season long habit. Use the tap furthest from where the water line enters the house, and use the cold side.
How do I thaw a frozen pipe safely?
Leave the faucet open, then warm the pipe with a hair dryer, a heat lamp kept at a safe distance, or hot towels, working from the faucet back toward the frozen section. Never use a torch or any open flame. If the pipe is inside a wall, call a plumber.
Why did my pipe burst after it thawed?
The ice plug holds water back while it is frozen. The split in the pipe wall is already there, but you do not see water until the ice melts and pressure returns. That is why you should watch for leaks as temperatures come back up after a freeze.
Does PEX pipe freeze and burst?
PEX expands more than copper or CPVC, so it often survives a freeze that would split rigid pipe. It is not freeze proof, and the brass fittings at each connection can still fail. Insulation is still worth doing on PEX in unheated space.
Winter Plumbing Help Across the Triad
We can insulate vulnerable runs, replace a spigot that is already leaking, or come out fast if a line has already let go. All Star Plumbing of the Triad has been family owned in High Point since 2007 and covers Greensboro, Winston-Salem, Kernersville and the towns around them. Call (336) 462-1080 or get a free estimate.
