When the temperature drops below freezing, water sitting in pipes in cold parts of your home can turn to ice. You can stop most pipes freezing with a few cheap jobs done now: lag any exposed pipes, keep the heating ticking over during cold spells, fix dripping taps and make sure you know where your stop tap is.
Below, we cover where pipes are most at risk, how to thaw a frozen pipe safely and what to do if one bursts. One rule runs through all of it: never use a naked flame or blowtorch on a pipe, and keep well away from electrics if water is anywhere near them.
Why a frozen pipe can do so much damage
Water expands as it freezes. Inside a pipe, that ice can split copper or push a plastic joint apart. Often you won't know until the thaw, when water escapes from the split, sometimes inside a ceiling or behind a wall. A burst pipe can soak floors, ceilings and wiring in minutes, which is why a little preparation is worth it.
Where pipes are most likely to freeze
Pipes freeze where they're cold and the water in them isn't moving. The usual places are:
- pipes and the cold water tank in the loft, especially where they sit above the loft insulation
- pipes in a garage, outbuilding or under a suspended timber floor
- pipes that run along or through outside walls
- outside taps and the pipe that feeds them
- your boiler's condensate pipe, the plastic pipe that carries waste water from a condensing boiler to a drain outside
A frozen condensate pipe won't flood your home, but it will stop the boiler working. We've written a separate guide on how to fix a frozen condensate pipe.
Jobs to do before the cold weather arrives
Most of these cost very little:
- Lag exposed pipes. Lagging is foam insulation tube sold in DIY shops. It splits so you can push it over the pipe. Tape the joins and don't leave gaps at bends, valves and fittings.
- Insulate the cold water tank in the loft, including its lid.
- Fix dripping taps. Even a slow trickle can freeze and block a pipe.
- Drain your outside tap. If it has an isolating valve inside the house (a small valve on the pipe that feeds it), turn that off, then open the outside tap to let the water out. A tap cover gives extra protection.
- Find your stop tap and check it turns. The stop tap is the valve that shuts off the mains water to your home. It's usually under the kitchen sink. If it's stiff, don't force it, as an old valve can snap or start leaking.
- Get your boiler serviced. A boiler that fails in a cold snap leaves the whole house, pipes included, without heat. Our boiler servicing visit checks it's working safely before winter.
Keeping pipes safe during a cold spell
- Keep the heating on at a low setting when you're out or away, rather than switching it off completely. Many boilers and thermostats have a frost setting, which turns the heating on if it gets very cold indoors. Your manual will say if yours has one.
- On very cold nights, leave the loft hatch open for a while to let some warmer air in.
- Open the cupboard doors under sinks on outside walls so warm air reaches the pipes.
- If you're going away for a long time, ask someone to check on the house, or turn off the water at the stop tap before you go.
How to tell if a pipe has frozen
The usual sign is a tap that gives nothing, or only a trickle, or a toilet cistern that won't refill. You may also see frost on a pipe in the loft or under the sink. If the boiler shows a fault code on a freezing morning and gurgles, suspect the condensate pipe.
How to thaw a frozen pipe safely
If you can reach the frozen pipe and it looks undamaged, you can usually thaw it yourself:
- Turn off the water at the stop tap.
- Look along the pipe for splits, cracks or bulges. If you find any, go straight to the next section.
- Open the tap the pipe feeds, so water can escape as the ice melts.
- Warm the pipe slowly using hot water bottles or towels soaked in warm water. Start at the end nearest the tap and work back along the pipe.
- Once water is flowing again, turn the stop tap back on slowly and check the pipe for drips.
Never use a naked flame, a blowtorch or boiling water. Heating a pipe too fast can damage it, and a flame in a loft is a serious fire risk. If the frozen section is inside a wall, under a floor or somewhere you can't reach safely, leave it to a plumber.
What to do if a pipe bursts
Act quickly, in this order:
- Turn off the water at the stop tap. If it won't turn, contact your water supplier, who can turn off the supply outside your property.
- Keep safe around electrics. If water is near light fittings, sockets or appliances, switch off the electricity at the consumer unit (your fuse box), but only if you can reach it without standing in or touching water. If you can't, stay away and get help.
- Turn off the boiler and any immersion heater, then open the cold taps to drain the water left in the pipes.
- Soak up what you can with towels and move belongings. Photos help if you claim on your home insurance.
- Call a plumber to repair the pipe before you turn the water back on.
Our guide to a gas or water emergency at home explains what to do if you lose your water supply altogether.
How we help with frozen and burst pipes
When we're called out to a leak, we find where the water is coming from, replace the damaged section of pipe and check the joints either side of it. While we're there, we can lag exposed pipework or replace a stop tap that's seized, so you can shut off the water quickly next time you need to.
If you'd like pipes lagged, a stiff stop tap replaced or a leak repaired before the coldest weather arrives, Beales Services can help across South Woodford and nearby. You can book a visit through our plumbing services page.
