Frozen pipes: keeping them from freezing, and what to do when one does

Frozen pipes cause a large share of the winter insurance claims in the country, and the claim is rarely small, because the break happens inside a wall and the water runs until someone notices. The whole thing is preventable, and when it does happen, the first hour decides whether it is a repair or a rebuild.

Which pipes freeze

• Anything in an outside wall, especially a kitchen sink on a north wall.
• Pipes in unheated spaces: the garage, the crawlspace, an attic, a porch.
• Hose bibs with a hose still attached.
• Supply lines to a bathroom over a garage or a bump-out addition.
• Sprinkler systems and pool lines that were not blown out.
• Any pipe in a house where the heat was turned down or off.

Water expands about nine percent when it freezes. The ice itself does not usually split the pipe; what does is the pressure that builds between the ice plug and a closed faucet. That is why the standard advice is to leave a faucet dripping: it relieves the pressure and keeps the water moving.

Prevention

• Insulate the exposed pipes in unheated spaces with foam sleeves. It is the cheapest fix in the house.
• Heat tape on the pipes that freeze every year. Buy a listed product with a thermostat and plug it directly into a GFCI outlet, never into an extension cord.
• Seal the gaps where cold air reaches the pipes: the rim joist, the hole where the hose bib comes through, the gap around the dryer vent.
• On the cold nights, open cabinet doors, let the far faucet drip, and keep the house at 55 or above.
• If you leave for a week or more in winter, shut off the main and open the faucets to drain what you can. A house with the water off cannot flood.

When a faucet runs dry in a freeze

A faucet that gives nothing, or a trickle, on a cold morning has a frozen line somewhere between it and the main.

• Leave that faucet open. When the ice melts, the water needs somewhere to go.
• Find the frozen section. It is usually where the pipe is coldest: at the outside wall, in the crawlspace, near an air leak. The pipe may be frosty or bulged.
• Warm it gently. A hair dryer, a heating pad wrapped around the pipe, towels soaked in hot water, a space heater aimed at the wall. Start at the faucet end and work toward the ice so the melt has an exit.
• Never use a torch, a heat gun or anything with a flame. Houses burn down every winter from a torch on a pipe in a wall.
• If you cannot find the section, or it is inside a wall, call a plumber. They have pipe-thawing equipment and, more to the point, they can fix the break that may already be there.

If it has burst

Turn off the main. Then turn off the water heater, since an empty tank with the burner on will fail. Open the faucets to drain the lines. Move what you can, and call a plumber and, if the water reached drywall, insulation or flooring, a restoration Pro the same day. Drying a structure in the first 48 hours is the difference between fans and a demolition.

The main shutoff is the whole story here. Find it today, put a tag on it, and make sure everyone in the house knows where it is.