How to Prevent Frozen Pipes This Winter

Why Frozen Pipes Are Such a Problem

Every winter, the phones at Blimp Plumbing start ringing the moment the temperature drops below zero. Frozen pipes are one of the most common callouts we get across Portsmouth and Hampshire, and the damage they cause can be devastating.

Here's the thing most people don't realise: the problem isn't the freezing itself — it's the thawing. When water freezes inside a pipe, it expands by about 9%, which is enough to crack copper, split plastic, and burst joints. But you often won't know about it until the ice melts and water starts pouring out of the crack. That's when a frozen pipe becomes a burst pipe, and a minor annoyance becomes an insurance claim.

We've seen it too many times — ceilings collapsing, electrics shorting out, and entire rooms needing to be stripped back and replastered. The good news is that most frozen pipe incidents are entirely preventable with a bit of preparation.

Which Pipes Are Most at Risk?

Not all pipes in your home are equally vulnerable. The ones most likely to freeze are those in unheated or exposed areas:

• Loft spaces — Pipes running through your loft are exposed to near-outdoor temperatures. This is the single most common location for frozen pipes in Portsmouth's terraced houses.
• Garages and outbuildings — Any pipework in an unheated garage is at risk.
• External walls — Pipes that run along or inside external walls get colder than those on internal walls.
• Under suspended timber floors — Older properties in Fareham, Havant, and across Hampshire often have pipes running through draughty underfloor voids.
• Outside taps — The most exposed pipes of all.

How to Protect Your Pipes

1. Lag Your Pipes

Pipe insulation — known as lagging — is the single most effective thing you can do. Foam pipe lagging is cheap (about £1-£2 per metre from any hardware shop), easy to fit, and makes an enormous difference. Concentrate on all pipes in the loft, garage, along external walls, under floorboards, and connecting your outside tap.

The lagging clips around the pipe — make sure you cover the whole length with no gaps, paying particular attention to bends, joints, and valves where ice tends to form first. If you've got pipes in the loft, make sure the loft insulation goes over the pipes (between the pipes and the roof), not under them, so warmth from below can help.

2. Keep Your Heating On Low

When the temperature drops below zero — especially overnight — keep your heating ticking over on a low setting rather than switching it off completely. Setting your thermostat to 12-14°C overnight and when you're out during the day keeps enough warmth circulating to prevent pipes from freezing.

Yes, this uses a little more gas. But it uses far less than you'd spend fixing a burst pipe and the resulting water damage. Think of it as insurance for your central heating system.

3. Protect Your Outside Taps

Outside taps are the most vulnerable point in your plumbing. Before winter, turn off the isolation valve (usually under the kitchen sink), open the outside tap to drain remaining water, and fit an insulated tap cover from any garden centre. If you use an outside tap regularly in winter, consider having a frost-proof tap fitted instead.

4. Open Loft Hatches on Very Cold Nights

On nights when a hard frost is forecast, leaving the loft hatch slightly open allows warm air to rise into the loft. Even a couple of degrees can be enough to keep pipes above freezing.

5. Fix Draughts and Know Your Stopcock

Seal gaps in external walls and around pipe penetrations with expanding foam to keep cold air away from pipes. And make sure everyone in the household knows where the stopcock is — in most Portsmouth homes, it's under the kitchen sink. Test it now so it doesn't seize when you need it most.

What to Do If Your Pipes Freeze

Despite your best efforts, sometimes pipes still freeze. If you turn on a tap and nothing comes out on a cold morning, here's what to do:

First, turn off the stopcock as a precaution — if the pipe has cracked, this prevents a flood when the ice melts. Then thaw slowly using a hairdryer on low heat, hot water bottles, or warm towels wrapped around the pipe. Work from the tap end backwards. Never use a blowtorch or pour boiling water on a frozen pipe — we've seen both cause far worse damage than the ice itself.

As the pipe thaws, check carefully for leaks. If you spot a crack or a weeping joint, keep the water off and call a plumber.

Going on Holiday This Winter?

If you're heading away, your home is at higher risk. Before you leave: keep the heating on a low timer (12-14°C for a few hours morning and evening), turn off the stopcock and drain the taps if you'll be away more than a couple of days, ask a neighbour to check on the house, and leave the loft hatch slightly open.

When to Call a Professional

Some frozen pipe issues are beyond DIY. Pipes frozen inside walls need specialist equipment. If the same pipes freeze every winter, they may need rerouting — we can assess and re-pipe vulnerable sections. Burst pipes always need a professional — emergency leak repair is one of our most common winter callouts. And if your boiler's condensate pipe has frozen (causing a lockout), we can thaw it and insulate it to prevent it happening again.

Prepare Now, Not in January

The best time to prepare for frozen pipes is before the first hard frost — not after. A couple of hours spent lagging pipes and checking your heating system now could save you a miserable, expensive emergency in the middle of winter. And if you'd rather leave it to the professionals, give Blimp Plumbing a call. Scott and Fraser are always happy to check your pipework and make sure you're ready for whatever the Portsmouth winter throws at you.