Prevent or Thaw Frozen Pipes

Prevent or Thaw Frozen Pipes

Level: Beginner

During the winter, pipes can often freeze and then burst, leading to expensive repairs. However, bursting pipes are a nightmare that you can avoid by taking a few preventative measures. Taking the steps to protect the pipes in your home is an inexpensive project that will help keep your home in good repair and money in your wallet.

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  • Prevent Frozen Pipes: Insulate

    The best way to prevent pipes from freezing is to insulate them. Adding pipe insulation around accessible water pipes is economical and saves you money.

    • Step 1: Check Your Pipes

      To locate water pipes in your home that may need to be insulated, look for water pipes that pass through unheated spaces. These include crawlspaces, garages, attics and the pipe leading directly from your hot water heater.

    • Step 2: Take Measurements
      box cutter

      Before you insulate, measure the outside circumference and length of each section of pipe. Be sure to check the hot water lines as well. Hot water lines freeze slower than cold water lines, but they are more likely to burst. Add up the lengths for each size of pipe and add about 10 percent to that amount to account for waste or error.

      Helpful Tip

      To determine the pipe's diameter (which you'll need to know for purchasing insulation), measure the circumference of the pipe with a cloth tape measure and divide that number by 3.14 (pi).

    • Step 3: Get Insulation

      Once you know what size and how much insulation you need, you can purchase various types of pipe insulation kits at your local True Value hardware store. Be sure adhesive tape or contact cement is included for sealing. The most widely available pipe insulation is tubular foam that is slit lengthwise to slip over existing pipes. However, tubes without slits (designed for installation over new piping) can easily be slit with a sharp utility knife.

    • Step 4: Insulate and Seal

      Open the pipe insulation along the slit, press it onto the pipe and seal it with an adhesive tape or contact cement to prevent summertime condensation.

      Helpful Tips

      Double up. On particularly vulnerable sections of pipe, use two insulating tubes. The first tube is to fit the pipe circumference and the second tube is to fit the outside circumference of the wrapped pipe.

      Don't insulate pipes while they are hot, and (if possible) wait 36 hours after you've applied insulation and adhesive before circulating hot water.

    • Step 5: Make Adjustments If Needed
      foam pipe insulation

      When you're covering areas where pipes meet, it may be necessary to make adjustments by cutting the insulation to fit. For best results, use a miter box saw and either a serrated knife or a hacksaw. Use a single-edged razor blade for detail cutting. After making the appropriate cuts and confirming a good fit, use adhesive tape to seal the joint.

    • Step 6: Insulate Valves and Seal

      After insulating the straight sections of the pipe, you will need to protect the valves. Preformed valve covers are the easiest and most effective method. Simply fit the two halves over the valves and seal the edges with adhesive tape. For hard-to-cover valves, you can use strips of foam or fiberglass that are designed to wrap around pipes or fittings.

      To provide maximum protection for pipes that are highly vulnerable to freezing, add electrical pipe-heating cable to foam insulation. Prior to adding foam insulation, simply attach the cable to the length of the pipe, or wrap around the pipe and connect to the power supply.

      Safety Alert!

      If using electrical pipe-heating cable, always follow the manufacturer's instructions for safe and proper installation.

      Helpful Tips

      For greater prevention against frozen pipes, do not set your thermostat below 60 degrees.

      Leave under-sink cabinet doors open at night or on very cold, windy days.

      Keep a heat lamp in a relatively confined space, but exercise caution.

      Disconnect outside hoses and lawn sprinklers during the winter months.

      Add outdoor faucet protectors to prevent faucets from freezing.

    Repair and Thaw Pipes

    Despite what many think, expanding ice inside a pipe is not what causes a pipe to burst. It's the high water pressure that builds up between the blockage and the faucet as the ice continues to form, so the pipe doesn't always burst where it is frozen. If you discover a frozen pipe, leave the sink valve open a bit to offer relief from the excessive pressure.

    In case you don't get a chance to insulate before the first freeze of winter, here are some other measures you can take to repair and/or thaw pipes.

    • Step 1: Survey for Damage

      Find out how much damage has occurred. Open the faucet at the end of the pipe and close the valve that runs into it. Check for holes, cracks or breaks along the pipe. Even if the pipe has been compromised, don't panic.

    • Step 2: Repair the Pipe

      Some pipe repairs are easy. For example, a pinhole can be repaired by simply wrapping the pipe with electrical or duct tape and a hairline crack can be fixed with a pipe clamp.

      For larger cracks, try repairing them with a patch kit. Start by sanding the area around the break in the pipe with rough-grit sandpaper (at least an 80- or 100-grit). Put on rubber gloves and wet the patch, then wrap it around the pipe where it has burst. Start wrapping at the hole and work out from there; wrap at least 4 or 5 inches in both directions. Wrap it as tightly as possible and then press the patch down by hand to ensure a proper bond. Let the patch dry.

      For larger cracks that can't be repaired with a patch kit, you may need to replace that section of pipe. Consider calling in a professional plumber to complete this task.

    • Step 3: Thaw the Pipe
      ice coming from an outdoor faucet

      There are several different methods for thawing pipes. You can try using a hairdryer or heat gun on a low setting, placing a heat lamp or small electric heater near the pipe, or wrapping the pipe in heat tape or an electrical blanket. You can also try wrapping towels around the pipe and pouring hot water over them but, no matter which method you use, it should never include a torch.

      Helpful Tip

      When thawing a pipe that has burst, look for the shut-off valve to that section of pipe. If necessary, shut off the main water supply to prevent flooding as it thaws.

      Safety Alert!

      When using heat from a hairdryer, heat gun, heat lamp or electric heater, please be aware of wet floors and the potential danger of electric shock. Check the area. If you find potentially dangerous electrocution hazards or extensive damage to pipes, it is best to call a plumber for assistance.

    • Step 4: Insulate Pipes

      Once you're sure your patch works, insulate your pipes to prevent a frozen pipe problem next winter.

      Good job! Now you shouldn't have to worry about frozen pipes anymore.

  • Here’s what you’ll need to complete this project successfully.

    Before you begin, use the shopping list below to uncheck the tools you already have to complete this project.

    Then, print or save your updated list and bring it to your local True Value hardware store, where an expert Hardwarian will give you the remaining tools and expert advice you need to complete this project.

    You can also shop online for these project items at and receive FREE shipping to a participating store.

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