From the Ottawa Citizen:
Mike Holmes: Never do-it-yourself when pipes freeze
MIKE HOLMES, POSTMEDIA NEWS 03.01.2015
One of the worst things that can happen to your home during winter is a burst pipe. Repairing or replacing the pipe is one thing, but the real - and more costly - threat is the potential for water damage.
What causes a pipe to burst? Pressure, and usually that pressure is caused by the expansion of water when it freezes. (A clog can also cause a pipe to burst but freezing is the usual culprit.)
It's important to prevent frozen pipes by wrapping them (including hot water lines) and draining exterior plumbing lines. Also, turning off the exterior hose bib is not the same as shutting off the line; it must be shut off from the inside.
But what if a pipe is already frozen? In some cases it's unavoidable (for instance, during extreme weather conditions and power outages.) How would you know and what do you do?
The first sign of frozen pipes is no water flow from one faucet or fixture (like a shower head), but others in the house work fine.
If one pipe freezes other pipes nearby can freeze too, since they are in the same area of the house. So you should let a little bit of water drip from adjacent fixtures to keep water flowing before it freezes, and flush toilets every so often. You can do this when it's extremely cold and/or there's no power.
When people think of a pipe bursting they usually imagine water pouring down the walls, through the ceiling or onto the floor. But if a pipe bursts because water froze in it, the homeowner might not know it until the frozen section thaws. Then one day they come home and their house is flooded.
If you suspect a burst pipe, shut off the main water valve as a precaution. It's usually in the mechanical room in the basement, but every home is different. Next, call a licensed plumber. By code, all plumbing should be on the warm side of the insulation and vapour barrier. If not it should be rerun - a big, expensive job. A temporary solution is a heat tracer or heat-tracing system. But you will still eventually need to rerun the pipe, or pipe will freeze again once there's intense cold.
Sometimes plumbers use a heat tracer or heat-tracing system to get rid of ice blockages in pipes. It has two clamps that are attached to either end of the pipe and then an electrical current thaws the ice. There are also plug-in versions you can get at big-box stores to wrap around pipes vulnerable to freezing. They typically have a thermostat, so when temperatures drop they kick in.
Fixing frozen pipes is never a DIY job; you must call in a licensed, experienced plumber. They will know which pipes are affected and where they are without turning your walls into Swiss cheese.
If you don't have a licensed plumber you can trust in your list of contacts, one way to know if you're dealing with a professional is by calling. Most reputable plumbing businesses have a dispatcher. They will tell you if there are any plumbers in your area and the wait time.
If you call and you get someone's voice mail, or the plumber picks up the phone him or herself, chances are they've picked up twenty other calls that day and you will be waiting a very long time before anyone shows up. You're better off finding someone else.
Watch Mike Holmes on Holmes Makes It Right on HGTV. For more information visit makeitright.ca.