Why frozen pipes burst
When water freezes, it expands by about 9%. In sealed pipework, that expansion has nowhere to go — pressure rises until the pipe splits. The crack often appears between the freeze and a closed tap, but you don't see the damage until the pipe thaws and water gushes out.
1. Lag your pipes
Insulate exposed pipework with suitable pipe insulation. Concentrate on pipes in lofts, garages, outside walls, and unheated outbuildings. Cover every elbow, joint, and isolation valve — that's where they freeze first.
2. Drain outside taps
Turn off the isolation valve to your outside tap (usually inside the house, near the wall it exits through). Then open the outside tap to drain water out of the section that's exposed to frost. Leave it open through winter.
3. Keep heating on low
If you're away for more than a day or two, follow the heating manufacturer’s frost-protection guidance and check your insurer’s requirements for an unoccupied home.
4. Open cabinet doors
Pipes under sinks on outside walls (especially kitchens) get cold air and stay frozen longer. Open the cabinet doors to let warm room air circulate around them.
5. Know your stopcock
If a pipe does freeze and burst, you need to shut off the water immediately. Find your main stopcock now — usually under the kitchen sink or where the mains enters your house. Test it actually works (turn it off and check taps run dry).
What to do if a pipe freezes
Turn off the stopcock. Open the affected tap. Thaw the pipe gently — warm cloths if it is safe to do so, never a blowtorch. Keep electrical appliances away from water. Start at the tap end and work back. If the pipe has already burst, leave it for an emergency plumber.