Water has a unique property: It expands as it freezes. This puts tremendous pressure on whatever is containing it, including metal or plastic pipes. No matter the strength of the container, expanding water can cause pipes to break.
“Pipes that freeze most frequently are those that are exposed to severe cold, like outdoor hose bibs and water supply pipes,” said Bob Schultheis, natural resource engineering specialist for University of Missouri Extension. “Pipes located in unheated interior areas like crawl spaces, attics, garages, kitchen cabinets, and pipes that run against exterior walls are especially subject to freezing.”
Schultheis recommends installing specific products made to insulate water pipes like a pipe sleeve, or installing UL-listed heat tape, heat cable or similar materials on exposed water pipes. Many such products are available at your local building supplies retailer.
“Pipes should be carefully wrapped, with ends butted tightly and joints wrapped with waterproof tape,” said Schultheis. “Follow manufacturer’s recommendations for installing and using these products. Newspaper can provide some degree of insulation and protection to exposed pipes—even one-quarter inch of newspaper can provide significant protection in areas that usually do not have frequent or prolonged temperatures below freezing.”
Homeowners can take preventive action during cold weather, according to Schultheis.
• Disconnect water hoses from outdoor hose bibs. Place an insulating foam dome or other covering over the faucets. If possible, turn off indoor valves that supply the hose bibs and drain water from the pipes.
• Keep garage doors closed if there are water supply lines in the garage. Install a weather seal around the door opening.
• Open kitchen and bathroom cabinet doors to let warmer air circulate around the plumbing. In extreme cold weather, face an electric heater toward the pipes as well.
• When outdoor temperatures are very low, let the cold water trickle from the faucet served by exposed pipes. “Running water through the pipe—even at a trickle—helps prevent pipes from freezing because the temperature of the water running through it is above freezing,” said Schultheis.
• Keep the house thermostat set to the same temperature day and night.
“By temporarily suspending the use of lower nighttime temperatures, you may incur a higher heating bill, but you can prevent a much more costly repair job if pipes freeze and burst,” he said.
If you turn on a faucet and only a trickle comes out, suspect a frozen pipe. Locate the suspected frozen area of the water pipe immediately. The first places to look include pipes running against exterior walls and where your water service enters your home through the foundation.
Keep the faucet open. “As you treat the frozen pipe and the frozen area begins to melt, water will begin to flow through the frozen area. Running water through the pipe will help melt more ice in the pipe,” said Schultheis.
Apply heat to the section of pipe using an electric hair dryer or portable space heater (kept away from flammable materials), or by wrapping pipes with towels soaked in hot water.
“Do not use a blowtorch, kerosene or propane heater, charcoal stove, or other open flame device,” Schultheis warned. “A blowtorch can make water in a frozen pipe boil and cause the pipe to explode. All open flames in homes present a serious fire danger, as well as a severe risk of exposure to lethal carbon monoxide.”
Apply heat until full water pressure is restored. If you can’t locate the frozen area, or if the frozen area is inaccessible or you are otherwise unable to thaw the pipe, call a licensed plumber.
If one pipe freezes, others may freeze, too. Check all other faucets in your home to find out if you have additional frozen pipes.
“Be prepared for water leaks from pipes that have been frozen for several hours,” said Schultheis. “They may have cracked and can leak once they are thawed. Know how to turn off the water supply coming into your house to avoid water damage.”