Anyone living in areas where the weather hits the freezing point, has at one time or another experienced freezing pipes. People living in modular homes and trailers are especially prone to freezing pipes. When water freezes, it expands, causing pipes to break because the water has no place to go during expansion.
Prevention, of course, is a lot better alternative than pipe replacement. Leaving a faucet at the farthest point from the water source dripping allows movement of water in the pipe, and controls freezing. The use of heat tapes on pipes in crawl spaces helps stop freezing. Wrapping pipes with foam rubber sleeves or fiberglass insulation works well. Always insulate both hot and cold pipes.
If pipes become frozen, but have not yet burst, there are methods to follow to thaw them. Never use an open flame torch to thaw frozen pipes. This is a safety hazard because generally you are working in tight spaces, and fire could be the result of using an open flame torch. Instead, first attempt to thaw frozen pipes by placing a space heater as close as possible to the pipes that are frozen. Open a faucet to allow steam and ice to escape. You can also use a hairdryer to thaw pipes. If extreme caution is used, a heat gun, such as one used for removing paint, works well.
If you do experience pipes breaking from freezing, the average DIYer can fix them. Generally, there are three types of pipes in the home, depending on the age of the building. Steel pipes are present in older homes. Copper pipes are used extensively, as are CPVC pipes. Let's examine and repair all three.
Unlike copper and PVC pipes, steel pipes are threaded on joints, couplings, and other fittings. If the pipe bursts along the seam, a pipe clamp can be used for repair. Peen the seam over with a ball peen hammer, and install the pipe clamp. If it must be replaced, there are several options. Remove the damaged pipe after thawing is complete with a pipe wrench, and replace the damaged pipe. Each end of the replacing pipe must be threaded. Because the average homeowner does not have pipe threading equipment, this can be handled at many hardware stores. Replace the pipe, using pipe thread sealant.
Another alternative to replacing a steel pipe is to replace the damaged steel pipe with a rigid CPVC pipe. Be sure to check with building codes for your particular area before attempting this. If you can do so in your area, there are transition couplings available that make the replacement a snap. Threaded plastic couplings are attached to the original steel pipe or fittings.
Run the pipe after couplings are made. CPVC pipe can easily be cut with a hacksaw or tubing cutter, making it easy to replace pipe length. The pipes are then joined using the "solvent welding" method. A special PVC cement is applied to the areas to be joined, and the cement melts and fuses the pipe together. this method is easy to do, but must be done correctly to prevent leakage of the pipe after installation.
Replacing a copper pipe is a bit more difficult than working with CPVC pipe. The biggest rule in soldering copper pipe is that it must be clean. There must also be no water present during installation. Shut off water to the source and drain the pipe. Steam buildup will occur during soldering and can cause injury. Water present during the soldering makes the operation difficult. Never attempt to simply resolder the copper joint that is leaking.
Always disassemble the joint and begin fresh. Heat the joint with a propane torch until the joint can be pulled apart. Be sure to use pliers to pull it apart - the pipe will be very hot. Take a little extra time to thoroughly clean the joint of any remaining solder and any residue from the pipe and the joint. Use a knife and sandpaper to accomplish this. If you are replacing old pipe with new pipe, sand the pipe with fine emery cloth to remove any grease or residue.
Once everything is clean, and the pipe has been cut to length, you are ready to apply the solder. Apply a small amount of lead-free flux to the pipe and inside of the joint. Fit the two together, and twist to ensure the flux is spread over the fitting. Using a propane torch, heat the joint. You do not need a large flame to accomplish this - set the torch to about a 3 inch flame to do the job. Hold the flame against the joint for a few seconds, and then move to the backside of the fitting to ensure even heat distribution.
To test to ensure the joint is hot enough, touch the lead free solder to the joint and determine if the solder runs freely around the joint. If so, then apply the solder to several places around the joint to ensure that the solder melts freely into all parts of the joint. Do not use the flame to run the solder - it will only blow the solder out of the joint. Wipe the joint with a rag, being sure not to burn yourself in the process. To test the joint, turn on the water source, allow it to build pressure, and inspect the joint for leaks. If it does leak, the only alternative you have is to reheat the joint, take it back apart, clean it, and begin again.