Plumbing & water
Stop your pipes freezing this winter
Water expands as it freezes, and it does not negotiate with copper. The split happens silently overnight; the flood waits politely for the thaw. An afternoon of lagging in October is the whole defence, and it costs less than one emergency call-out.
By the Tickover team · Published 15 June 2026 · 4 min read
The pipes that burst are the ones in unheated air: loft runs sitting above the insulation, outside taps, garage pipework, and anything crossing a draughty underfloor void. A heated house protects its own plumbing; your job is the pipework the heating never reaches.
The autumn afternoon that prevents it
The winter-proofing list
- Foam lagging on every pipe you can see in the loft
- Insulate over and around the loft tank, never beneath it
- Outside taps: isolation valve closed, tap open, insulated cover on
- Garden hose disconnected (trapped water freezes back into the tap)
- Boiler condensate pipe lagged where it runs outside
- Stopcock found, tested and labelled
- Heating set to 12°C or more whenever the house is empty
- Loft hatch left ajar during a hard freeze
Two of those deserve explanation. The loft tank stays unlagged underneath on purpose, so rising warmth keeps it liquid. And the stopcock drill is here because a frozen pipe may already be a split pipe: at thaw, the stopcock is all that stands between you and the ceiling.
The freeze calendar
- Lag loft pipes, jacket the tank
- Isolate and drain the outside tap
- Cold months: heating never fully off
- Away? Leave the heating at 12°C
- First warm spell: check for splits
Already frozen? Thaw it gently
The tell is one tap giving nothing while the rest of the house runs, usually on the year’s coldest morning. Do not attack the pipe with serious heat: if the ice has already split it, the thaw is when the water arrives.
The safe thaw
Find the frozen section
Follow the pipe that feeds the dead tap. Look for frost, condensation or a slight bulge, usually in the loft, the garage or against an outside wall.
Open the affected tap
Melting water needs somewhere to go, and returning flow tells you the moment you have won.
Stand ready at the shut-off
Know exactly where the stopcock is before you warm anything. If a split shows itself, you want the water off in seconds, not minutes.
Warm it gently, from the tap end back
Warm towels, a hot water bottle, or a hairdryer on low, kept moving and well away from wet surfaces. Never a blowtorch, heat gun or boiling water.
Watch it as it thaws
Stay with the pipe until water runs freely and every joint is dry. A split announces itself now, not later.
Thawing rules
Do
- Open the tap fed by the frozen pipe before warming it
- Thaw from the tap end back toward the blockage
- Keep watch for splits as the ice retreats
- Lag the pipe afterwards, so there is no next time
Don’t
- Never use a blowtorch, heat gun or naked flame
- Never pour boiling water on a pipe, warm only
- Do not leave a thawing pipe unattended
- Do not blast one spot with fierce heat, ease the whole run
The same cold snap freezes boiler condensate pipes, which is why boilers lock out on the coldest morning of the year: thawing a frozen condensate pipe is its own five-minute job, warm water only, on pipework you can reach from the ground.
Not sure what you’re dealing with?
Frozen tap or a suspicious damp patch? Self-Diagnose grades the urgency and lines up a vetted plumber before a small problem becomes the February story.
Lagging is one line in the winter-proofing weekend, and an empty house over the holidays deserves the empty-home checklist too. The rest of the system lives in the home plumbing guide.
Quick answers
What temperature should I leave my heating at to stop pipes freezing?
Around 12°C, constantly, whenever the house is empty in winter. The boiler’s own frost setting only protects the area around the boiler, while a steady background temperature keeps lofts, extensions and pipe runs on outside walls above freezing. Many insurance policies require a minimum heating level during winter absences, so check yours.
How do I thaw a frozen pipe safely?
Open the tap the pipe feeds, then warm the pipe gently from the tap end backwards using warm towels, a hot water bottle or a hairdryer on low. Never use a naked flame, and never boiling water. Watch the pipe the whole time and know where your stopcock is: splits reveal themselves as the ice retreats.
Which pipes freeze first in a house?
The ones outside the heated envelope: outside taps and their feeds, loft pipework sitting above the insulation, pipes in garages and unheated extensions, and runs crossing draughty underfloor voids. Cold plus moving air is the killer combination, which is why lagging plus draught-proofing beats either alone.
Should I drain my water system for a long winter absence?
For an absence of several weeks, draining down (or leaving heating on with someone checking the house) is the belt-and-braces answer, and some insurers require one or the other; check your unoccupancy clause. A plumber can drain and refill the system for roughly an hour’s labour at each end.
This guide is general information for UK homes, not advice about your specific property. Anything involving gas must be done by a Gas Safe registered engineer, and notifiable electrical work by a qualified electrician. If you smell gas, call the National Gas Emergency line on 0800 111 999. If you’re ever unsure, stop and get a professional in — that’s exactly what Tickover is for.
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