Thawing Frozen Water Pipes and Winterizing

Pipes that are not sufficiently insulated may freeze during cold weather. The result could be a minor inconvenience -- the pipes may be undamaged and the water will flow again when they thaw out. Or it could be a burst pipe.

Exposed pipes are easily insulated or heated. If the pipes are inside a wall, the job may be difficult. If the exterior wall is the inside wall of an attached garage, consider attaching solid foam insulation on the garage side of the entire wall. Otherwise you'll have to remove the exterior or interior wall covering (whichever is easier), insulate the pipes, and then reinstall the wall covering.

If the weather forecast calls for extreme cold and you fear that a pipe may freeze, open a faucet or two on the line just a crack, so water comes out in little more than a drip. Moving water freezes more slowly than still water.

Checklist

Time
An hour or two to protect exposed pipes; much more time to protect pipes behind walls

Tools
Portable heater, hair dryer, or heat gun; carpentry tools if you need to get at hidden pipes

Skills
Identifying and locating the pipes that need to be protected

Prep
Check the history of freezing pipes in your home; locate the vulnerable ones.

Materials
Insulation (various types), electric pipe-heating tape

Wrap exposed pipes with sections of foam insulation or fill the surrounding area with fiberglass batts, loose-fill cellulose, or spray foam. Leave part of the pipe exposed to warm, interior air.

Newer types of electric pipe-heating tape are easy to install and turn themselves on only when needed. Wrap the tape around the pipe and plug the unit into a reliable electrical receptacle. Follow the manufacturer's instructions. Never overlap electric heat tape.

Using a PVC saw or scissors-type PVC cutters, cut out a section of pipe. Take into account the fact that the pipes will slide into the valves at each side. Remove burrs from the pipes.

Make sure the valve fits. Apply primer outside the pipe and inside the valve. Cement one pipe and one side of the valve. Immediately slip the valve onto the pipe. Give it a slight twist and hold it for 30 seconds. Glue the other side.

When cold weather approaches, disconnect and drain all outdoor hoses. To protect the outdoor faucet (called a hose bib or sill cock), shut off the line that runs to it and open it to drain the water. To protect it further, strap on a foam insulator like this one. A long-term solution is to install a freezeproof sill cock that has the valve body indoors, protected from freezing temperatures.

If a cabin will be left unheated during the winter, take steps to prevent pipe damage due to freezing water. In addition to the steps shown, turn off the main shutoff valve and open a pipe nearby to let water drain out. Drain all water-using appliances, such as the dishwasher and clothes washer. If the cabin has hot-water heat, drain the heating system. Some cabins have small drain valves on the pipes; open them.

When water stops flowing during cold weather, you know that at least one pipe has frozen. (If only the hot water flows, you know the cold-water pipe has frozen.) A frozen pipe may or may not crack; you'll find out only after the water thaws. Just in case, watch the pipes continually and be prepared to shut off the water. Have pipe repair materials on hand. If a pipe is exposed, thaw it by pointing a hair dryer or heat gun at it. (Don't get too close with the heat gun, and watch carefully for any drip or spray of water.)

If the pipe is hidden in a wall, aim a portable heater at the area.