Prevent frozen pipes before the first frost

A frozen pipe is the most expensive winter emergency a landlord or homeowner can face. The pipe freezes overnight, expands, and splits. By morning the temperature has risen, the ice melts, and water pours through ceilings for hours before anyone notices. Insurance claims for 'escape of water' average £8,000–£15,000 per incident. The whole problem is preventable with a 30-minute autumn job.

**Step 1 — Lag every exposed pipe.** Foam pipe lagging (£3–£5 for 1m lengths from any DIY shed) wraps copper and plastic pipework in lofts, garages, outhouses and external walls. Use 22mm lagging on 22mm pipe and 15mm on 15mm. Pay particular attention to bends, joints and tees — they're where heat is lost fastest and where pipes typically split. Don't forget the cold water tank in the loft and the overflow pipe.

**Step 2 — Service the outside taps.** Locate the isolation valve for any outside tap (usually inside the property near where the pipe exits the wall). Turn the isolation valve off, then open the outside tap to drain any residual water and leave the outside tap open over winter. Water in a closed outside tap expands when it freezes and splits the pipe behind the wall — exactly where you can't see it until it's thawed and flooding.

**Step 3 — Open the loft hatch in cold snaps.** During sustained sub-zero weather, leave the loft hatch open by 5–10cm. Warm air rises into the loft and protects pipes and tanks. Counter-intuitive, but the marginal heating cost is trivial compared to a burst tank flooding the property below.

**Step 4 — Leave heating on a frost-protect setting.** If you're leaving a property empty for more than 48 hours over winter, do not switch the heating off. Set it to a constant 12–15°C (or use the frost-protect setting on the boiler if available). Most modern thermostats have a holiday mode that does this automatically. The £15–£30 of extra heating cost is the cheapest insurance you'll ever buy.

**If you're too late and a pipe has frozen.** Open the tap downstream of the frozen section first — when the ice thaws, water has somewhere to go. Then warm the pipe gradually with a hairdryer on a low setting, working from the tap end back toward the frozen section. Never use a blowtorch, kettle or boiling water — sudden thermal shock cracks copper. If you can't see the frozen section, turn the stopcock off and call a plumber — and find the stopcock now, before you need it in a panic.