Cold snaps are one of the most common causes of burst pipes in the UK. The reasons are simple physics, not bad luck. Understanding what's happening inside the pipe helps you prevent it.
The Physics of a Frozen Pipe
Water expands as it freezes, taking up roughly nine percent more space than it did as a liquid. Inside a pipe, that expansion has nowhere to go. Pressure builds between the ice and the nearest closed tap or bend.
Eventually, the pipe wall gives way under that pressure, usually splitting along its length. The crack often doesn't show itself until the ice thaws and water starts flowing again. As a result, a burst can seem to appear from nowhere on the first mild day after a freeze.
Which Pipes Are Most at Risk
Pipes in unheated spaces are the most vulnerable. Lofts, garages, and outside walls all sit outside your home's normal heating, so they cool faster than the rest of the house. Similarly, pipes running through an exterior wall cavity are more exposed than those buried inside warm internal walls.
Exposed outdoor pipework, such as an outside tap or a supply line to a shed, is also at risk. These sections have little protection from the surrounding air temperature. In particular, a spell of hard frost can freeze an exposed section within a single night.
Lagging and Heating: The First Line of Defence
Pipe lagging is inexpensive and straightforward to fit yourself. Foam sleeves slide over most pipe diameters and wrap around bends with a bit of extra material. Cover any pipe in a loft, garage, or under-floor void before winter sets in properly.
Keeping your heating on low during a cold snap, rather than switching it off completely, helps too. A consistent background temperature stops pipework from dropping to freezing overnight. Consequently, even an unoccupied property is less likely to suffer a burst if the heating stays on low.
What to Do During a Cold Snap
Knowing where your stopcock is matters more in winter than any other season. If a pipe does split, shutting off the water quickly limits the damage. Locate it now, rather than searching for it during an emergency.
Dripping a tap slightly during extreme cold can also help, since moving water is less likely to freeze than still water. This is worth doing overnight on the coldest nights of the year. It's a small habit that can prevent a much bigger problem.
If a Pipe Has Already Burst
If you're dealing with a burst pipe right now, shut off the water at the stopcock first. Our burst pipe repair service covers the fix once the immediate danger is under control. An emergency plumber can also isolate and repair a badly split pipe safely.
Request a quote online any time, day or night, and mark your request urgent if water is actively escaping.
Where to get help
A frost-split pipe can flood a property fast, so our flooding emergency response team is on call all winter. Afterwards, a damaged run may need pipe relining service rather than digging. Local help is available in Newcastle upon Tyne and Gateshead.
Related reading
For the steps to take in the moment, see our guide to emergency plumbing, or browse our full range of services for everything else we cover.