Most homeowners only think about their pipes when something goes wrong — a burst pipe in winter, a damp patch on the ceiling, or an unexpectedly high energy bill. The good news is that pipe lagging is cheap, easy to install yourself, and prevents all three.
What Is Pipe Lagging?
Pipe lagging is the insulation wrapped around water pipes to control their temperature and protect them from the environment. The term "lagging" is the traditional British name for pipe insulation — still widely used by plumbers and heating engineers across the UK.
Modern pipe lagging is typically made from:
- Closed-cell foam (Armaflex) — flexible, self-adhesive options available, ideal for most domestic applications
- Mineral wool (Rockwool) — better for high-temperature pipes and fire-rated applications
- Phenolic foam (Kingspan Kooltherm) — thinnest section for the same performance, used where space is tight
Where to Lag Pipes at Home
Loft pipes — the highest priority. Once you insulate your loft floor, the space above gets much colder. Any water pipes running through the loft must be lagged with at least 25mm wall thickness to prevent freezing.
Under-floor pipes — pipes running under suspended timber floors in older properties are exposed to cold air from below. Lag these with 19mm–25mm Armaflex.
Boiler pipework — the pipes immediately around your boiler and hot water cylinder lose significant heat if uninsulated. Lagging these reduces heat loss and helps your boiler run more efficiently.
Cold water pipes in humid areas — under-sink pipes in kitchens and bathrooms can sweat in summer, causing drips and mould. Closed-cell Armaflex stops condensation forming on the pipe surface.
Garage and outbuilding pipes — any pipe in an unheated space is a frost risk. Lag with minimum 25mm wall thickness.
DIY Installation — It's Easier Than You Think
For most domestic pipes (15mm, 22mm, 28mm) the process is straightforward:
- Measure the pipe bore — 15mm, 22mm or 28mm for most UK domestic pipework
- Choose the right wall thickness — 13mm for heated spaces, 25mm for frost protection
- Slit the insulation along its length and snap it onto the pipe
- For self-seal Armaflex — peel the backing strip and press the seam closed
- For standard Armaflex — apply adhesive to both faces of the slit, allow to tack, press closed
- Cut 45° mitres at bends using a sharp knife
How Much Does It Cost?
A 2m length of 15mm Armaflex self-seal pipe insulation costs from around £3. A typical loft with 10–15 pipe runs can be fully lagged for under £50 in materials — a fraction of the cost of a plumber's call-out after a burst pipe.
Products We Recommend for Home Use
- Armaflex Self-Seal Pipe Insulation — easiest for DIY, no glue needed
- Armaflex Class O Pipe Insulation — standard split tube, use with Armaflex adhesive
- Armaflex Adhesive — essential for a vapour-tight seal on cold water pipes
Shop the full range at pipelagging.com.
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