Preventing frozen pipes in an Edmonton winter

Why pipes freeze and burst

When water freezes it expands. In a pipe, the ice plug squeezes the water between it and a closed tap, and pressure builds until the pipe or a fitting splits. Often the leak only shows up when the pipe thaws, which is why a burst pipe can surprise you days after the cold snap.

In Edmonton, the risk spikes during long stretches at -25 C to -35 C, especially with wind. Chinooks can make it worse: a quick thaw followed by a hard freeze catches lines that drained or shifted.

The damage is rarely just the pipe. Water from a split line can run for hours before anyone notices, soaking insulation, drywall and flooring. In a basement it can reach the furnace, the water heater or the electrical panel. Prevention is far cheaper and easier than cleanup.

Most frozen pipes are in predictable places. If you know where yours are, you can protect them before January.

The usual trouble spots

• Exterior walls, especially kitchen sinks on outside walls and bathrooms over garages.
• Floors over cantilevers and bump-outs, common in 1990s and 2000s Edmonton homes.
• Attached garages, where water lines to a laundry or a sink pass through.
• Hose bibs that were never winterized, or frost-free bibs installed level instead of sloped.
• Crawl spaces and unheated additions, especially with vents left open.
• Attics, where some homes have lines for a humidifier or a second-storey bathroom.

Renovations can create new problems. A basement development that adds a bathroom on an outside wall, or a garage conversion that moves a laundry, can put a water line somewhere colder than before. If a line started freezing after a renovation, that is a clue.

Commercial and industrial buildings add their own spots: loading docks, sprinkler lines in unheated areas, rooftop equipment, makeup air units and lines in parkades.

Habits that help

Many freeze-ups can be prevented without any new equipment:

1. Shut off and drain outdoor taps in the fall, and disconnect hoses.
2. Keep the house at a steady temperature, even when you travel. Do not turn the heat way down on a long trip in January.
3. Open cabinet doors under sinks on outside walls during cold snaps so warm air reaches the pipes.
4. Keep the garage door closed, and seal gaps at the bottom.
5. Close crawl space vents for winter if your home was built that way, and insulate exposed pipes.
6. During extreme cold, let a tap on a problem line run with a small trickle.

Make a note of which lines froze in past winters. A line that freezes once is likely to freeze again in the next cold snap, and it is the first place to add protection.

Insulation on pipes helps, but it only slows heat loss. A pipe in a space that stays below freezing will freeze eventually, insulated or not. That is where heat trace comes in.

When heat trace is the right answer

Heat trace adds a small, controlled amount of heat to the pipe so it stays above freezing. It is a good fit for:

• Water lines that cannot be rerouted out of a cold space.
• Mobile and modular homes with water lines under the floor.
• Lines into detached garages, shops and barns.
• Commercial lines at docks, parkades and rooftops.
• Fire sprinkler and drain lines that must stay liquid.

A listed plug-in kit can be fine for a single short line, as long as it plugs into a GFCI-protected outlet and has a built-in thermostat. For longer runs, multiple lines, or anything critical, a hard-wired system on its own circuit with a proper controller is safer and more reliable.

Heat trace must be the right type for the pipe material, installed under insulation, and never wrapped or overlapped unless the product allows it. See heat tracing basics for how a full system is put together.

Fall check before the first deep freeze

If you already have heat trace, check it in October or early November:

• Plug in or switch on the system and confirm the indicator light comes on.
• Press TEST on the GFCI or ground-fault breaker, then reset it.
• Look along the pipe for torn insulation, wet spots or crushed cable.
• Check that the thermostat is clean and has not been moved away from the pipe.

If your heat trace is plugged in, make sure it is plugged directly into a GFCI-protected outlet, not into a power bar or an indoor extension cord. If the outlet itself is cracked or loose, have it replaced before winter.

For buildings with several circuits, our heat trace maintenance visit includes testing each circuit and providing a written report.

If a pipe freezes anyway

If no water comes out of a tap, or only a trickle, the line may be frozen. Know where your main shut-off valve is before you need it. Warm the area gently with a hair dryer or space heater kept well away from water, and open the tap so melting water can escape.

Watch for leaks as it thaws. If a pipe has split, shut off the water and call a plumber. If water has reached outlets, light fixtures or the panel, keep clear and call an electrician.

Common questions