Frozen Pipes around the Home


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Water has a remarkable property: on freezing, it expands approximately 9%. That’s easily enough pressure to split pipes. Frozen pipes in winter are at best an inconvenience, but they threaten to be much more. If pipes freeze sufficiently to cause a leak, then things can really get out of control: in addition to the cost of repairing burst pipes or damaged valves, costly and disruptive flooding can result.


Know your house

Much of preventing frozen pipes involves knowing your house; be aware of which pipes are most likely to freeze and at what outside temperature pipes are at risk of freezing. While the temperature displayed on your thermostat may never vary, inside walls and cupboards things will be much colder than the inside temperature.

The weather’s beautiful; “Wish you were here”

The temptation to save heating costs when leaving home for a few days or longer must be weighed against the increased risk of pipes freezing. If you turn down your household temperature too far, pipes that normally would not cause any trouble might become vulnerable to freezing. And, if you are going to be away for more than a short time, it’s possible that unpredicted and colder than usual weather could set up a scenario for burst pipes, as might a loss of heating caused by a furnace failure or extended power outage.

Added to the increased risk of bursting pipes in such a situation is the risk that flooding following a burst pipe might go on for days. Nobody needs that disaster.

When leaving home in the winter, it’s a good idea generally to have someone looking after your home doing things such as collecting mail and making your home look occupied and active. Add to this house-sitting responsibility looking out for cold snaps and heating loss.

Better still, if leaving for an extended period of time, turn off the water at the main service valve in the basement and open the taps to drain the water from your plumbing lines. You will still probably also wish to have someone check your home regularly.

Simple prevention measures

If you are hit with a cold snap and are unprepared by having pipes protected from the cold, leave a tap running. Opening a tap just at trickle will keep water moving to prevent freezing; in the event a pipe still freezes with a tap open, the open tap will help to relieve pressure that might otherwise rupture a pipe. Choose a tap farthest from the point where the water supply enters the house; also, choose a tap downstream of the point in the pipe most likely to freeze.


Additional simple measures include:

  • Insulating accessible pipes passing through cold areas. Even temporary wrapping with newspaper will help.
  • Keeping garage doors closed if there are water supply lines in the garage
  • Opening the doors of cupboards containing pipes that meet exterior walls
  • Placing space heaters in critical locations. If the heater will be left unattended, use an oil filled heater to reduce the risk of fire.


Simple seasonal measures include:
Draining and insulating outdoor (garden) faucets. Insulating domes are available to cover faucets and hose bibbs.
In summer cottages and places that will not be used in winter, draining the water piping, draining under-counter traps, and opening faucets.

Longer-term prevention

Longer-term preventative measures are those that will protect your home from frozen pipes season after season. Such measures include:

  • Better insulation inside walls to protect from outdoor cold
  • Re-routing pipes away from exterior walls
  • Insulating pipes along their length
  • Installing a pipe heating cable system
  • Rebalancing central heating to deliver more heat to vulnerable areas
  • Investing in backup heaters
  • Re-routing pipes away from areas vulnerable to cold (cold cellars, basement crawl spaces, garages)


Thawing frozen pipes

Open the tap at the end of the frozen pipe

If you lose water flow in a cold snap, you quite likely have a frozen pipe. Steps to prevent more serious freezing damage may also restore your water flow.

First, leave the tap open on the frozen pipe until water is flowing unimpeded. An open tap will help relieve pressure caused by freezing.

Next, apply heat as directly to the frozen area as possible, or as near as you can reach. A hot towel or electric blanket is good. Expose the pipe and cold area to warm air: a heat gun or hair dryer are options. Do not use a blowtorch or open flame to prevent the risk of fire.


Thawing a frozen pipe can take hours, so be patient. Once water flow is restored, leave a trickle flowing until the risk of refreezing is past.


When you are getting back to normal, check that the pipe is undamaged by inspecting the pipe, shutting off the faucet, and monitoring closely to ensure that no leaks have been created. If you find that the freezing has burst a pipe or started a leak, shut off the main water supply and call a plumber. Master Drain can help.

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